• Clinical Abstracts

    Clinical Abstracts on Transesophageal Cardioversion and Defibrillation

    The induction of atrial flutter and fibrillation and the termination of atrial flutter by esophageal pacing. Kerr CR; Gallagher JJ; Smith WM; Sterba R; German LD; Cook L; Kasell JH Pacing Clin Electrophysiol (United States), Jan 1983, 6(1 Pt 1) p60-72. In patients with Wolff-Parkinson-White syndrome (WPW), it is important to assess the ventricular response during atrial flutter or fibrillation since conduction across the accessory pathway during these atrial rhythms may cause hemodynamic impairment or life-threatening ventricular arrhythmias. We have recently reported the effective use of an esophageal electrode in pacing the atrium. In this study we prospectively assessed the ability to induce atrial flutter and fibrillation by esophageal pacing in 23 patients with WPW or other electrophysiological abnormalities. An esophageal bipolar electrode with 29 mm interelectrode distance was positioned in the esophagus to record the most rapid and largest esophageal electrogram (mean distance of 36.6 +/- 2.9 cm (SD) from the nares). Pacing was performed at cycle lengths of 40-340 ms (mean 166 +/- 72), pulse durations of 7.0-9.9 ms, and currents of 10-25 mA. Atrial flutter alone was induced in 6 patients, fibrillation alone in 11 patients, and both arrhythmias in 5 patients. In one patient neither flutter nor fibrillation was induced by esophageal pacing, and fibrillation was induced only with difficulty using intracavitary pacing. Of the 11 patients with flutter, the arrhythmia was terminated in 8 by esophageal pacing at cycle lengths of 160-220 ms (mean 176 +/- 18 ms). All patients tolerated the procedure well with only mild to moderate discomfort. Therefore, esophageal pacing appears to offer an effective, well tolerated method of initiating atrial fibrillation and flutter and terminating atrial flutter and offers a potentially useful noninvasive method of following patients serially. 

    Cardioversion of persistent atrial flutter in non-anticoagulated patients at low risk for thromboembolism. Bertaglia E, D'Este D, Franceschi M, Pascotto P. Department of Cardiology, Civil Hospital, Mirano, Italy. mbertaglia@shineline.it. Ital Heart J 1(5):349-53, 2000. BACKGROUND: The true risk of thromboembolic events after cardioversion of atrial flutter was not addressed carefully. Nevertheless, thromboembolic events were thought to be rare and less likely to occur after cardioversion of atrial fibrillation. The aim of this study was to prospectively evaluate if the interruption of persistent typical atrial flutter could be safely performed without anticoagulation in a group of patients at low risk for thromboembolic events. METHODS: We studied 64 subjects selected among 138 consecutive patients with persistent typical atrial flutter (minimal duration 72 hours) in whom a transesophageal atrial pacing was performed in our electrophysiology laboratory from October 1994 to May 1999. Exclusion criteria included: anticoagulation therapy during the previous 4 weeks; previous history of atrial fibrillation; recent (< 1 month) myocardial infarction; history of thromboembolic events; left ventricular ejection fraction  40%; presence of moderate or severe mitral regurgitation or stenosis; induction of sustained (> 6 hours) atrial fibrillation during transesophageal atrial pacing. Patients in whom atrial flutter persisted in spite of transesophageal atrial pacing underwent external direct current cardioversion or right atrial overdrive pacing within 24 hours. Thromboembolic events were checked for 4 weeks after the restoration of sinus rhythm. RESULTS: Sinus rhythm was restored in 54 patients by transesophageal atrial pacing, in 8 patients by electrical cardioversion, and in 2 by right atrial pacing. The mean duration of atrial flutter was 18 +/- 19 days, the mean left atrial size 41.3 +/- 6.2 mm, and the mean left ventricular ejection fraction 54.8 +/- 7.3%. During the study period no episodes of thromboembolism were recorded. CONCLUSIONS: Cardioversion of persistent typical atrial flutter in non-anticoagulated patients at low risk for thromboembolic events appears safe. 

    Transoesophageal low-energy cardioversion of atrial fibrillation. Results with the oesophageal-right atrial lead configuration. Santini M, Pandozi C, Colivicchi F, Ammirati F, Carmela Scianaro M, Castro A, Lamberti F, Gentilucci G. Department of Cardiology, San Filippo Neri Hospital, Rome, Italy. Eur Heart J 21(10):848-55, 2000. BACKGROUND: Low energy internal cardioversion is a safe and effective procedure to restore sinus rhythm in patients with atrial fibrillation refractory to external cardioversion. However the procedure is invasive and fluoroscopy is mandatory. Aim of the study To assess the efficacy, safety and tolerability of a new simplified procedure of low energy internal cardioversion. METHODS: Twenty-five consecutive patients (19 males and 6 females) with persistent atrial fibrillation were submitted to low energy internal cardioversion using a step-up protocol (in steps of 50 V, starting from 300 V). A large surface area lead (cathode) was positioned in the oesophagus, 45 cm from the nasal orifice. A second large surface area lead (anode) was positioned in the right atrium. A quadripolar lead was positioned at the right ventricular apex to achieve ventricular synchronization and back-up pacing. Oesophageal endoscopy was performed within 24 h of the end of the procedure and repeated after 48 h, if injury to the oesophageal mucosa had occurred. RESULTS: Sinus rhythm was restored in 23 patients (92%) with a mean delivered energy of 15.74 J (range 5-27) and a mean impedance of 48 Omega. In two patients, endoscopy revealed that small burns had occurred in the oesophageal mucosa. Such lesions spontaneously healed after 48 h. CONCLUSIONS: This new technique of performing low energy internal cardioversion is effective and safe and avoids the positioning of a lead in the coronary sinus or in the left pulmonary artery, thereby simplifying the procedure.

    The sensitivity of transesophageal pacing for screening in atrial tachycardias. Kesek M, Sheikh H, Bastani H, Blomstrom P, Lundqvist CB. Department of Cardiology, Akademiska Hospital, Uppsala University, Sweden. milos.kesek@medicin.uu.se. Int J Cardiol 72(3):239-42, 2000. Transesophageal atrial pacing and recording performed in 128 patients for palpitations or tachycardia was retrospectively evaluated and compared to the same procedure in 77 routinely evaluated patients after a catheter ablation procedure. The sensitivity and specificity of the described protocol was 74 and 90% respectively. The procedure was well tolerated and a majority of patients could be completely evaluated according to the protocol. The outcome of the first time investigation influenced the subsequent choice of therapy in the studied population. The results suggest that transesophageal pacing is a valuable tool for evaluation of atrial tachycardias with specificity, sensitivity and tolerability comparable to other noninvasive methods used in cardiology. 

    Termination of tachycardias by transesophageal electrical pacing. Volkmann H, Dannberg G, Heinke M, Kuhnert H. Univ of Jena, Germany. Pacing Clin Electrophysiol 1992 Nov;15(11 Pt 2):1962-6. To evaluate the therapeutic significance of noninvasive transesophageal pacing for termination of tachycardias the method of rapid atrial or ventricular transesophageal pacing was used in 233 patients with different tachycardiac arrhythmias. We were able to terminate atrial flutter in 136 of 162 patients by transesophageal rapid atrial stimulation (conversion to sinus rhythm in 75 cases, induction of atrial fibrillation in 61 cases). Atrial tachycardias were interrupted in 17 of 23 patients (sinus rhythm in 11 cases, atrial fibrillation in six cases). AV reciprocating/AV nodal supraventricular reentry tachycardias were terminated in 62 of 63 patients (sinus rhythm in 58 cases, atrial fibrillation in four cases). By transesophageal rapid ventricular pacing ventricular tachycardias could be terminated in ten of 15 patients. The success rate of transesophageal pacing was influenced by the pacing rate, by the type of tachycardiac arrhythmia inclusive by the type of atrial flutter and by the tachycardia's cycle length. Because the success rates are comparable with invasive technique and the procedure is simpler, the noninvasive transesophageal antitachycardiac pacing should be respected as the method of the first choice in patients with supraventricular tachycardias. 

    Atrial pacing for conversion of atrial flutter in children. Campbell RM, MacDonald D, Jenkins JM  C.S. Mott Children's Hospital, Ann Arbor, MI. Pediatrics 1985 Apr;75(4):730-6. Twenty-three successive patients with 27 different episodes of sustained atrial flutter were treated with atrial pacing for conversion of the tachyarrhythmia; 15 patients with 16 episodes of atrial flutter underwent intracardiac right atrial pacing and 8 patients with 11 episodes of atrial flutter were treated with transesophageal atrial pacing. Ten of sixteen episodes (63%) and 8/11 episodes (73%) were successfully converted using intracardiac and transesophageal techniques, respectively. Mean flutter cycle length for all 27 episodes was 219 msec (mean heart rate 274 bpm); successful pacing conversion cycle length (n=15) was 72% of the flutter cycle length. Hemodynamic, electrophysiologic, and x-ray data were not predictive of conversion by either technique. Induction of localized atrial fibrillation or failure to meet critical pacing criteria may explain pacing failures. Based on this experience we recommend a trial of transesophageal atrial pacing for acute conversion of any episode of atrail flutter in children prior to direct current cardioversion.

    Transesophageal study of recurrent atrial tachycardia after atrial baffle procedures for complete transposition of the great arteries. Butto F, Dunnigan A, Overholt ED, Benditt DG, Benson DW Jr. Am J Cardiol 1986 Jun 1;57(15):1356-62. Transesophageal study was used for diagnosis and treatment of 51 episodes of tachycardia in 13 patients with complete transposition of the great arteries who had undergone atrial baffle procedure. At the time of atrial baffle procedure, patients were 6 to 36 months old (mean 23). Tachycardia (1 to 17 episodes per patient) first occurred 1 to 23 days (4 patients) or 1.8 to 12 years (9 patients) after atrial baffle. Transesophageal study was performed using a bipolar silicone rubber-coated catheter. Tachycardia conversion was accomplished with stimulation bursts using 4 to 10 stimuli 9.9 ms in duration at 20 to 28 mA and an interstimulus interval of 50 to 100 ms less than the atrial cycle length. All tachycardia episodes had regular atrial cycle lengths ranging from 200 to 350 ms. In 12 patients, second-degree atrioventricular (AV) block was observed during tachycardia, suggesting primary atrial tachycardia. However, in 1 patient, occurrence of AV block always resulted in tachycardia termination, suggesting the presence of AV reentrant tachycardia. Transesophageal stimulation converted 48 of 51 tachycardia episodes to sinus/junctional rhythm. Ten tachycardia episodes in 6 patients were transiently converted to atrial fibrillation lasting 3 seconds to 28 minutes before spontaneous conversion to sinus junctional rhythm. Conversion attempts were unsuccessful on 3 occasions. Acceleration of ventricular rate after stimulation necessitated DC cardioversion on 1 occasion. Conversion was not achieved in 2 tachycardia episodes using stimuli less than 10 mA. Transesophageal study is a safe and effective minimally invasive technique for diagnosis and treatment of tachycardia in infants and children who have had atrial baffle for transposition of the great arteries.

    Transesophageal electroconversion of atrial reentrant tachycardias early or late following surgery for congenital heart disease. Hessling G, Brockmeier K, Rudiger HJ, Ulmer HE. Abt. Padiatrische Kardiologie Universitatskinderklinik, Heidelberg. Z Kardiol 88(2):97-102, 1999. Atrial reentrant tachycardias (ART) are a potentially life-threatening complication in survivors of congenital heart disease surgery. From July 1993 to December 1997, temporary transesophageal pacing was used to convert 29 tachycardia episodes in 19 patients. At the time of the first tachycardia episode, patients' ages were 1 month to 26 years (mean 9.8 yrs). Time from operation to onset of first tachycardia episode ranged from 1 day to 19 years. Onset was within the first 2 weeks postoperatively in 6 patients and occurred later in 13 patients (1 to 19 years after operation). Postoperative pacemaker implantation had been performed in 2 pts; 17 of 19 pts were receiving antiarrhythmic medication. After placing a quadripolar transesophageal catheter, atrial and ventricular signals were recorded and atrial stimulation performed. Atrial cycle length of tachycardia ranged from 160-380 ms with 1:1 to 4:1 AV conduction. Temporary transesophageal pacing was performed following an algorithm starting with 4 extrastimuli (20 ms below atrial cycle length of tachycardia). Tachycardia terminated in 27 of 29 cases (93%) without complications. In 3 cases, conversion was achieved by pacing after amiodarone 5 mg/kg i.v. After tachycardia conversion, sinus- or pacemaker rhythm was present in 20 cases. In 9 cases atrial fibrillation was recorded; spontaneous conversion to sinus rhythm occurred after a maximum of 3 min (7 cases) or persisted and required direct current cardioversion (2 cases). In conclusion, transesophageal atrial pacing is an effective, relatively noninvasive method for conversion of atrial reentrant tachycardias after operation for congenital heart disease. 

    Transesophageal stimulation in the treatment of atrial flutter and tachysystole. Gallay P, Bertinchant JP, Lehujeur C, Errera J, Leenhardt A, Grolleau R, Puech P. Arch Mal Coeur Vaiss 1985 Mar;78(3):311-6. Transoesophageal left atrial pacing was used to reduce 102 episodes of ectopic atrial rhythms (79 common flutters and 23 ectopic tachycardias) in 83 patients (64 men, 19 women) aged 33 to 85 years (average 61 years). Overdrive pacing, at a faster rate than that of the spontaneous rhythm, was delivered via a bipolar pacing catheter introduced nasally and positioned behind the atrium under fluoroscopic and/or electrocardiographic control. Long pulse durations (up to 20 ms) were used to capture the atria with intensities of less than 20 mA for better tolerance. The overall results were: a) conversion to sinus rhythm in 60.8% of cases (47% directly and 13.8% after transient atrial fibrillation), b) atrial fibrillation lasting over 24 hours 7.8% of cases, c) failure (31.4%) due to non-capture or intolerance (20.6%) or recurrence of the arrhythmia after transient atrial fibrillation (10.8%). Atrial flutter is more accessible to pacing than tachycardia (restoration of sinus rhythm in 63.3% and 52.2%, respectively). Arrhythmias in the postoperative period of cardiac surgery, and isolated and recent arrhythmias were more easily converted. Prior antiarrhythmic therapy did not seem to improve results. Fifty per cent of failures of oesophageal pacing were converted to sinus rhythm by endocavitary pacing. These results show that atrial flutter or tachycardia may be successfully treated by oesophageal pacing in over 50% of cases without having to use other forms of electrotherapy (endocavitary pacing or cardioversion).

    Transesophageal low-energy synchronous cardioversion of atrial flutter/fibrillation in the dog. Yamanouchi Y, Kumagai K, Tashiro N, Hiroki T, Arakawa K. Fukuoka University, Japan. Am Heart J 1992 Feb;123(2):417-20. The purpose of this study was to determine the feasibility and efficacy of terminating atrial flutter/fibrillation using low-energy synchronous shocks delivered through a transesophageal catheter in dogs with talc-induced pericarditis. Atrial flutter/fibrillation was induced by employing the pulse train method. The minimum effective cardioversion energy level was compared for three different methods--method A, delivery between a distal esophageal electrode and a proximal esophageal electrode; method B, delivery of shocks through a distal esophageal electrode and a plate placed on the chest; method C, transthoracic cardioversion. The minimum effective cardioversion energy level did not differ significantly between methods A and B (1.30 +/- 0.46 joules versus 1.29 +/- 0.35 joules). Transesophageal cardioversion decreased the defibrillation threshold three-to-fourfold from that of conventional transthoracic cardioversion. There were no complications of heart block, ventricular fibrillation, or any pathologic evidence of esophageal injury. Thus transesophageal low-energy synchronous cardioversion is considered a feasible and effective method for the treatment of atrial flutter/fibrillation.  

    Clinical utility and the predictors of outcome of overdrive transesophageal atrial pacing in the treatment of atrial flutter. Kantharia BK; Mookherjee S. Veterans Affairs Med Ctr, Syracuse. Am J Cardiol, Jul 15 1995, 76(3) p144-7. Transesophageal atria pacing (TEAP) using a pill electrode was performed in 49 patients with atrial flutter. The responses observed were (A) immediate sinus rhythm in 17 (35%), (B) delayed sinus rhythm in 13 (27%), (C) atrial fibrillation in 11 (22%), and (D) no success in 8 (16%) patients. Sinus rhythm was thus restored in 30 patients (61%). In group A, 12 of 17 patients (p < 0.05) had coronary artery disease. The patients in group D had echocardiographic evidence of right atrial enlargement (2.56 +/- 0.29 cm, p < 0.007), left atrial enlargement (4.6 +/- 0.12 cm, p < 0.0001), right ventricular dilatation (3.41 +/- 0.45 cm, p < 0.05), left ventricular dilatation (6.39 +/- 0.66 cm, p < 0.05), and depressed left ventricular ejection fraction (32 +/- 7%, p < 0.05). Optimal pacing rate (375 +/- 54 beats/min) was 41% higher than the mean atrial flutter rate (266 +/- 37 beats/min) for cardioversion to immediate sinus rhythm. Pacing current strength and the pulse width had no influence on the final outcome. On the basis of the result of the initial attempt, patients undergoing TEAP repetitively had an almost predictably similar outcome on the subsequent attempts. Thus, normal sinus rhythm could be resumed in most patients with atrial flutter by TEAP. It does not require general anesthesia and can be performed even in patients who have undergone digitalization, when a direct-current countershock may be of some concern. 

    Transesophageal stimulation in the treatment of atrial flutter and tachysystole. Factor influencing immediate results. Girardot C, Diebold H, Morelon P, Dentan G, Fraison M, Eicher JC, Bouhey J, Louis P. Hopital du Bocage, Dijon. Arch Mal Coeur Vaiss 1988 Nov;81(11):1379-84. The effectiveness and safety of transoesophageal atrial pacing in the treatment of atrial flutter and tachycardia have been well demonstrated. The purpose of this study was to determine the factors that could influence the results of this method at the end of the procedure. Seventy-seven transoesophageal atrial pacings were performed in 62 unselected consecutive patients with either flutter or atrial tachycardia. The following parameters could be evaluated in 55 patients: date of onset of the arrhythmia, echocardiographic diameter of the left atrium, maximum amplitude of oesophageal atrial potentials, voltage and frequency of stimuli in the last stage of pacing. Our results can be summarized as follows: In both flutter and atrial tachycardia taken globally, conversion to sinus rhythm was obtained in 37% of the cases, and conversion to atrial fibrillation in 46.7% of the cases. The failure rate was 19.4%; all failures were due to lack of atrial capture during pacing. The main factor of transoesophageal atrial capture is voltage. Patients must be able to tolerate the voltage needed for capture. In the case of flutter, when capture was achieved a normal-sized left atrium and a high maximum amplitude of oesophageal atrial potentials were factors indicating that conversion to sinus rhythm could be expected. This, however, did not apply to atrial tachycardia. -- Whatever the type of tachyarrhythmia, the more recent its onset the easier its reduction.

    Conversion of atrial flutter in pediatric patients by transesophageal atrial pacing: a safe, effective, minimally invasive procedure. Rhodes LA, Walsh EP, Saul JP. Children's Hospital, Boston. Am Heart J 1995 Aug;130(2):323-7.   Atrial reentry tachycardia, often termed atrial flutter, is an arrhythmia that is uncommon in the general pediatric population but is seen frequently in patients with congenital heart disease. One goal in treating the arrhythmia is to terminate it, returning the atrium to its underlying rhythm. This report describes the use of transesophageal atrial pacing to attempt termination of atrial reentry in 102 pediatric patients (158 episodes). The patients ranged in age from 1 hour to 41.5 years. Conversion was successful for 112 (71%) of 158 episodes. Six of the 112 episodes required an infusion of procainamide after initial attempts at pacing led to atrial fibrillation. There were no significant differences between the ages of patients or the duration of the tachycardia in comparing successful versus unsuccessful conversions. In contrast, the atrial cycle lengths for the successfully converted tachycardias were significantly greater than for unsuccessful attempts. Transesophageal atrial pacing is a safe and effective means of terminating atrial flutter in the pediatric population. It is minimally invasive, it can often be performed in an outpatient setting, and the technique may occasionally be facilitated by infusion of intravenous procainamide. 

    A comparison of transoesophageal atrial pacing and direct current cardioversion for the termination of atrial flutter: a prospective, randomised clinical trial. Tucker KJ, Wilson C. Department of Medicine, Naval Hospital, Oakland, California. Br Heart J 69(6):530-5, 1993. OBJECTIVE--To compare the safety and efficacy of transoesophageal atrial pacing (TAP) with an easily swallowed pill electrode and direct current cardioversion (DCC) in patients with atrial flutter that was refractory to appropriate medical treatment. DESIGN--Prospective, randomised clinical trial. SETTING--Community based United States naval hospital. SUBJECTS--Twenty one consecutive patients with refractory atrial flutter selected consecutively from the inpatient cardiology consultation service. All patients were hemodynamically stable and medical treatment with a class IA or IC antiarrhythmic agent had failed. Eleven patients were treated with TAP and 10 patients were treated with DCC. INTERVENTIONS--Digoxin was given to all patients to control the ventricular rate to < 100/minute. MAIN OUTCOME MEASURE--Conversion to normal sinus rhythm and arrhythmias after cardioversion. RESULTS--Conversion to normal sinus rhythm was similar in both groups (TAP 8/11, DCC 9/10, p = 0.31). Arrhythmias after cardioversion including third degree heart block and non-sustained ventricular tachycardia were more frequent in the DCC group (TAP 0/11, DCC 6/10, p = 0.02). CONCLUSION -- Transoesophageal atrial pacing with an easily swallowed pill electrode is safe, well tolerated, and is as efficacious as DCC for refractory atrial flutter. 

    Transoesophageal pacing for perioperative control of neonatal paroxysmal supraventricular tachycardia. Stevenson GW, Schuster J, Kross J, Hall SC. Children's Memorial Hospital, Department of Anesthesia, Chicago, IL 60614. Can J Anaesth 1990 Sep;37(6):672-4. The perioperative management of a 16-day-old infant with recurrent supraventricular tachycardia (SVT) is discussed. Vagal manoeuvres and medication were not adequate in controlling the SVT. Since the patient was scheduled for extensive surgery in the prone position, it was decided to use transoesophageal pacing as the method of choice for conversion of SVT. Transoesophageal pacing succeeded several times in overriding the SVT and restoring normal heart rate and haemodynamic variables. The advantages and disadvantages of various methods of treating SVT in the newborn are discussed.

    Type II atrial flutter interruption with transesophageal pacing: use of propafenone and possible change of the substrate. Doni F, Staffiere E, Manfredi M, Piemonti C, Todd S, Rimondini A, Fiorentini C. Ponte San Pietro, Bergamo, Italy. Pacing Clin Electrophysiol 1996 Nov;19(11 Pt 2):1958-61. Type II atrial flutter (AFII) is an arrhythmia which usually cannot be interrupted by atrial pacing: the underlying mechanism is considered to be a leading circle without an excitable gap. We investigated whether the administration of propafenone, an antiarrhythmic drug, which primarily decreases conduction velocity, has a beneficial effect on AFII interruption using transesophageal pacing. Twelve patients with an AFII were randomized into 2 groups in which pacing was performed without treatment (group A) or two hours after the administration of 600 mg of oral propafenone (group B). Sinus rhythm was attained in 0 of 6 patients in group A and in 4 of 6 patients in group B (P < 0.05). The baseline mean cycle length was the same in both groups (175 +/- 7 (A) vs 168 +/- 8 ms (B); it lengthened significantly after the administration of propafenone (219 +/- 33 vs 168 +/- 8 ms; P < 0.05). Propafenone did not significantly lengthen the cycle in the two patients in whom interruption of the arrhythmia was impossible. Our data show that propafenone has a facilitating effect on atrial pacing only when it significantly prolongs the cycle length of the arrhythmia, possible expression of a conversion of AFII into type I, with an anatomical substrate and an excitable gap allowing arrhythmia capture and interruption. In the two patients in whom sinus rhythm was not restored, the absence of a direct dependence of the cycle length on the change in conduction velocity induced by propafenone may be explained by the persistence of a functionally determined circuit, resistant to atrial pacing.

    Atrial flutter termination by overdrive transesophageal pacing and the facilitating effect of oral propafenone. Doni F, Della Bella P, Kheir A, Manfredi M, Piemonti C, Staffiere E, Rimondini A, Fiorentini C. Policlinico San Pietro, Bergamo, Italy. Am J Cardiol 1995 Dec 15;76(17):1243-6. Transesophageal overdrive atrial pacing is effective and safe for atrial flutter termination. The influence of antiarrhythmic drug therapy on this procedure is controversial. In this study, we investigated whether oral propafenone may facilitate this procedure. Thirty patients with type I atrial flutter were randomized into 2 groups in which transesophageal pacing was attempted: group A, without treatment; and group B, after oral administration of propafenone 600 mg. Transesophageal pacing was effective in interrupting atrial flutter in 53% of patients (8 of 15) in group A and in 87% of patients (13 of 15) in group B. A significant lengthening of the flutter cycle was observed with respect to the baseline in patients given propafenone (261 +/- 23 vs 217 +/- 25, p < 0.01). Sinus rhythm resumed at a shorter paced cycle in group A patients (166 +/- 13 vs 187 +/- 14 ms, p < 0.01). The transesophageal threshold for stable atrial capture was significantly lower in group A (20.5 +/- 0.2 vs 23.3 +/- 1.2, p < 0.01). In no patient was the threshold for atrial capture higher than the pain threshold. We did not observe abrupt enhancement of atrioventricular conduction. We conclude that propafenone is effective and safe when used with transesophageal pacing in the termination of atrial flutter. The slowing effect of the drug on intraatrial conduction and the possible stabilizing effect on the reentry circuit appear to be outweighed by the positive effect of propafenone on the excitable gap of the circuit, facilitating its capture and accounting for the beneficial effect of the drug on arrhythmia termination.

    Efficacy of intravenous propafenone in termination of atrial flutter by overdrive transesophageal pacing previously ineffective. D'Este D, Bertaglia E, Mantovan R, Zanocco A, Franceschi M, Pascotto P. Divisione di Cardiologia, O.C. Mirano. Am J Cardiol 1997;79(4):500-2. Fifty patients with symptomatic type I atrial flutter in whom termination of the arrhythmia with transesophageal stimulation was unsuccessful were randomized to undergo a repeat procedure after intravenous propafenone (n = 25) or placebo (n = 25). Immediate sinus rhythm recovery rate was 36% in the propafenone group and 4% in the placebo group (p = 0.005), indicating that intravenous propafenone increases the rate of successful transesophageal stimulation and can be used when a first attempt at conversion is ineffective.

    Combined transesophageal left atrial pacing and antiarrhythmic therapy in the treatment of atrial flutter. Matiouchine GV, Shulman VA, Balog AI, Bezruk AP, Golovenkin SE. Krasnoyarsk Medical Academy, Russia. Pacing Clin Electrophysiol 1996;19(11 Pt 2):1947-50 In order to terminate atrial flutter (AF) overdrive transesophageal left atrial pacing (TELAP) was performed in 760 patients with paroxysmal AF. There were 315 women and 415 men (mean age 59 years). In 260 patients, TELAP was used in an outpatient setting. Approximately half of the patients (51%) had coronary artery disease and/or arterial hypertension, and 23% of the patients had no structural heart disease. The duration of AF ranged between 1 hour and 1 month. TELAP was performed in 312 patients without any antiarrhythmic drug (AAD) administration (group I) and in 448 patients after administration of AAD (procainamide and/or amiodarone) in conventional doses (group II). TELAP resulted in immediate return of sinus rhythm in 85 patients (27%) of group I and in 222 patients (50%) of group II (P < 0.001). TELAP converted AF to atrial fibrillation (AFIB) in 185 of group I (59%) and in 214 (48%) of the group II patients (P < 0.01). In addition, within 1-2 days after TELAP AFIB converted to sinus rhythm spontaneously or after AAD in 87 patients of group I (28%) and in 84 (19%) of the group II patients (P < 0.01). In general sinus rhythm was restored in 172 (55%) of the group I and in 306 (68%) of the group II patients (P < 0.005). AF was converted to AFIB in 98 (31%) of the group I and in 130 (29%) of the patients in group II patients (NS). TELAP was ineffective in 42 (13.5%) of the group I and in 12 (3%) of the group II patients (P < 0.001). TELAP was an effective noninvasive method for the treatment of recent onset AF. Our experience showed that after TELAP, sinus rhythm was restored in most of the patients with paroxysmal AF within 1-2 days. In some patients TELAP converted AF to AFIB, making it easier to control the heart rate with AAD. Treatment with AAD before TELAP increased its effectiveness.

    A method of intensive therapy for atrial flutter. Lipnitskii TN, Radnin AG, Stepaniuk AV, Kotsuta GI. Klin Med (Mosk) 1993;71(5):41-4. The authors propose a new stepwise method of intensive therapy of atrial flutter (AF) based on atrial transesophageal pacing (ATEP) the efficacy of which was raised by previous digitalization. Patients of group 1 (n = 25) were scheduled to have ATEP, in its inefficacy ATEP was to be followed by antiarrhythmic drugs and on-demand cardioversion. In patients of group 2 (n = 27) ATEP was preceded by digitalization. ATEP and antiarrhythmic chemotherapy resulted in restoration of the sinus rhythm in 48% of the cases, cardioversion was performed in 11 patients of group 1. In group 2 normal rhythm was reestablished in 88% of the patients, 2 patients experienced cardioversion. The proposed variant of treatment is advocated as an alternative to cardioversion.

    Rapid transesophageal and transvenous atrial stimulation. Prager H, Pachinger J, Haiderer O, Sterz H. II. Medizinischen Abteilung, Landeskrankenhauses Klagenfurt. Wien Med Wochenschr 1987 Aug 15;137(14-15):330-1 Rapid atrial stimulation (RAS) is a very effective method of treatment of paroxysmal supraventricular tachycardia (PSVT). Substained AV nodal reentrant PSVT could not be terminated by administration of different antiarrhythmic drugs in 19 patients. Transesophageal pacing was performed in 10 patients successfully - in 2 patients following verapamil intravenous administration. In the remaining 7 patients in whom this procedure failed the PSVT could be terminated by transvenous RAS - in 3 patients following the intravenous injection of verapamil.

    The use of transesophageal electrical stimulation of the left atrium combined with the intravenous administration of kordaron for managing paroxysms of atrial flutter. Potapenko PI, Kapustin AI, Strukov VV. Vrach Delo 1991 Aug;(8):44-7. The efficiency was studied of transesophageal electrocardiostimulation of the left ventricle (TEESLP) in controlling attacks of atrial fibrillation in patients with cardiac insufficiency as well as its association with preliminary administration of cordaron. Treatment was carried out in 19 patients. After (TEESLP) the attack was controlled in 15 patients (76.3%). In cases where primary TEESLP was inefficient TEESLP was repeated after administration of cordaron in doses that do not inhibit the contractile capacity of the myocardium. It proved possible to control the paroxysm in 93% where primary TEESPL failed. There was relationship between the sizes of the left atrium and the result which permits to predict the efficacy of this method.

    Direct Conversion of Atrial Flutter to Sinus Rhythm with Low-Output, Short-Duration Transesophageal Atrial Pacing  Ajisaka H, Hiraki T, Ikeda H, Kubara I, Yoshida T, Ohga M, Imaizumi T.Clin Cardiol. 1997 Sep; 20(9): 762-766. The effect of low-output, short-duration transesophageal atrial pacing (TAP) on the conversion of 31 patients with paroxysmal atrial flutter (PAF) was investigated. Sixteen patients (52%) were converted directly to sinus rhythm and 12 (38%) to atrial fibrillation. Transesophageal pacing was ineffective in three (10%) patients. The patients who had a direct conversion to sinus rhythm had longer flutter wave cycle lengths than those converted to atrial fibrillation (248 vs. 221 ms, p<0.005). No patient had complications and complained of any symptoms. Thus, low-output, short-duration TAP was useful to convert PAF directly to sinus rhythm without side effects.

    Therapeutic effectiveness of left atrial transesophageal electric stimulation in atrial flutter. Batutin NT, Diadyk AI, Bagrii AE, Malovichko SI. Kardiologiia 1992 Feb;32(2):64-6. The efficiency of frequent asynchronous transesophageal electrical stimulation (TEES) of the left atrium in atrial flutter of various origin was analyzed in 62 patients. It was found to be depended on the etiology and duration of arrhythmia and on the frequency of atrial waves. The best results were obtained in patients with postmyocardial cardiosclerosis and coronary heart disease in acute arrhythmias and at a low (less than 300 per min) frequency of flutter waves.

    Therapeutic value of esophageal stimulation. Factors influencing the results in flutter and atrial tachysystole. Chabert JP, Metz D, Chapoutot L, Doucet J, Laudinat JM, Elaerts J, Blaise C, Bajolet A. Hopital Robert-Debre, Reims. Ann Cardiol Angeiol (Paris) 1991 Feb;40(2):69-74. The aim of this prospective study was to identify factors predicting the efficacy of atrial stimulation by esophageal route in 57 nonselected patients between 37 and 88 years of age and admitted for intensive care due to flutter or atrial tachycardia. It was impossible to perform the procedure correctly in 4 patients. The restoration of sinus rhythm was achieved in 28.3% of cases at the end of the procedure and in 47.2% of cases after 24 hours. These results were influenced by the duration of the arrhythmia, the underlying cardiopathy and the diameter of the left atrial, but were not affected by the stimulation parameters.

    Relation of parameters of frequent transesophageal electric stimulation of the atria during the treatment of atrial flutter and electrophysiologic characteristics of the myocardium. Zubrin IuV. Kardiologiia 1989 Jul;29(7):46-9. After arresting paroxysms with frequent transesophageal cardiostimulation (TECS), 20 patients with coronary heart disease accompanied by episodes of Type 1 atrial flutter (AF) were studied by using a technique of intracardiac electrophysiological examination. The length of the atrial cycle in AF was found to correlate with that of successful TECS (r = 0.83). The correlation increases when a difference of atrial functional and effective refractory periods is subtracted from the length of the atrial cycle in tachycardia (r = 0.92). The equations of simple and multiple linear regression were derived, which defined the optimal frequency parameters of stimulation with a sufficient accuracy to stop Type I AF episodes. The efficacy of frequent TECS in arresting 324 spontaneous AF episodes was 92.9%.

    Cardioversion of tachycardias by transesophageal atrial pacing. Montoyo JV, Angel J, Valle V, Gaus C. Ciudad Sanitaria de la Seguridad S. Am J Cardiol 1973 Jul;32(1):85-90. Transesophageal atrial pacing by means of an electrode catheter placed in the esophagus was attempted in 22 patients tor treatment of the following tachyarrhythmias: paroxysmal supraventricular tachycardia (8 patilents), atrial flutter (6 patients), atrial fibrillation (3 patients), ventricular tachycardia (3 patients) and nonparoxysmal atrioventricular (A-V) junctional tachycardia (2 patients). Atrial pacing was definitely achieved in 17 patients, sinus rhythm was restored in 5 of 8 patients with paroxysmal supraventricular tachycardia and in 1 of 2 patients with nonparoxysmal A-V junctional tachycardia. Atrial pacing failed to restore sinus rhythm in all other types of tachyarrhyhmias treated. In 1 patient with ventricular tachycardia, there was no strong diagnostic evidence for the arrhythmia until atrial pacing was performed and ventricular capture beats became evident. The safety of transesophageal atrial pacing and its advantages over other methods of treatment of tachyarrhythmias are discussed. The results ot our study suggest that atrial pacing from the esophagus is the method of choice in the treatment of paroxysmal supraventricular tachycardias and perhaps of nonparoxysmal A-V junctional tachycardias in digitalized patients who require rapid suppression of the arrhythmia. there is also evidence that atrial pacing may be helpful in diagnosing some cases of ventricular tachycardia with a suspected ventricular origin. 

    CardioCommand notation: Endoscopy examinations of the esophagi were performed in patients having undergone transesophageal atrial pacing for cardioversion (n = 6) and treatment of bradyarrhythmias (n=12), one of whom had been paced for 30 hours. Two patients exhibited minor esophageal erosions which were interpreted as pressure necrosis of the mucosa, rather than coagulative due to hyperemia associated with electrical stimulation. The remaining 16 patients showed no evidence of esophageal injury.

    Overdrive atrial stimulation during transesophageal electrophysiological study: usefulness of post-pacing VA interval analysis in differentiating supraventricular tachycardias with 1:1 atrio-ventricular relationship. Tritto M, Dicandia CD, Calabrese P. Oncology Institute, Bari, Italy. Int J Cardiol 1997 Oct 31;62(1):37-45. We evaluated the feasibility and usefulness of overdrive atrial pacing to identify the relationship between atrial and ventricular activation in supraventricular tachycardias with a stable 1:1 atrio-ventricular (AV) conduction ratio during a transesophageal electrophysiological investigation. Overdrive atrial stimulation was performed in 42 consecutive patients (11 males and 31 females; mean age 49 +/- 17 years) during AV junctional reentrant tachycardia, orthodromic AV reentrant tachycardia and ectopic atrial tachycardia (22, 13 and seven subjects, respectively). Trains of 12 stimuli at a constant rate were introduced starting at a cycle length 10 ms shorter than the tachycardia cycle length; stimulation was repeated with a 10-ms decrement in pacing cycle length at each step until tachycardia terminated and/or second-degree AV block occurred. The difference between the VA interval duration at baseline and in the first post-pacing tachycardia beat was measured at each step and provided identification of the AV relationship. At least one post-pacing VA interval was evaluable in 90% of the cases and measured 2 +/- 4 and 1 +/- 3 ms in AV junctional and AV reentrant tachycardia groups, respectively, and 83 +/- 42 ms in the ectopic atrial tachycardia group (P < 0.0000001 ectopic atrial tachycardia group vs. others). When three or more post-pacing VA intervals were obtained during the same tachycardia, a curve was constructed by plotting their values against the corresponding pacing cycle lengths. A curve could be constructed in 36% of the cases and was flat in all patients with AV junctional and AV reentry, while it was completely irregular in the ectopic atrial tachycardia group (P < 0.003). The analysis of post-pacing VA interval behaviour in response to overdrive atrial stimulation provides a rapid and reliable differentiation between supraventricular tachycardias with 1:1 AV conduction ratio during a transesophageal electrophysiological study.

    Prospective evaluation of transesophageal pacing for the interruption of atrial flutter. Crawford W, Plumb VJ, Epstein AE, Kay GN. University of Alabama at Birmingham. Am J Med 1989 Jun;86(6 Pt 1):663-7. PURPOSE: Although transesophageal pacing has been used successfully for the interruption of cardiac arrhythmias, the efficacy of this technique for the interruption of spontaneous atrial flutter remains poorly defined. The utility of transesophageal pacing to interrupt atrial flutter that was persistent despite standard antiarrhythmic drug therapy (mean duration: 70.3 days; range: one day to more than 365 days) was studied prospectively in 39 consecutive patients. PATIENTS AND METHODS: After written informed consent was obtained from each patient, transesophageal pacing was performed with a programmable stimulator, using the distal electrode as the cathode and the proximal electrode as the anode. All patients continued to receive a type 1 antiarrhythmic drug or amiodarone throughout the period of transesophageal pacing. The response to transesophageal pacing was classified as follows: (1) direct conversion; (2) indirect conversion; or (3) failure to interrupt atrial flutter. RESULTS: The mean stimulus amplitude and pulse duration required for atrial capture were 19.8 +/- 7.5 mA and 18.4 +/- 7.9 msec. Atrial flutter was successfully converted to sinus rhythm by transesophageal pacing in 82% of patients. In 38% of patients, atrial flutter was converted directly to sinus rhythm without another intervening arrhythmia (direct conversion). The mean pacing rate required for direct conversion was 341 +/- 27 beats/minute. In 44% of patients, the cycle length of atrial flutter was accelerated to less than 180 msec or was converted to atrial fibrillation with spontaneous conversion to sinus rhythm within 24 hours (mean 8.4 +/- 9.3 hours, indirect conversion). The mean pacing rate inducing accelerated atrial flutter or transient atrial fibrillation was 372 +/- 61 beats/minute (p = NS compared to direct conversion). Atrial flutter was not interrupted or atrial fibrillation was induced that did not spontaneously convert to sinus rhythm within 24 hours in an additional seven patients (18%). The underlying cardiac disease, age, previous drug therapy, atrial size, atrial flutter cycle length, history of prior atrial fibrillation, left ventricular function, and concomitant medical illnesses did not predict the efficacy of transesophageal pacing. CONCLUSION: The present study suggests that transesophageal pacing is highly effective for interrupting spontaneous atrial flutter that does not terminate with standard antiarrhythmic drug therapy.

    Elective countershock in unanesthetized patients with use of an esophageal electrode. McNally EM, Meyere EC, Langendorf R. Michael Reese Hosp, Chicago. Circulation 33:124-127, 1966. No abstract was published with this article.
    CardioCommand notation: A sequence of 20 shocks of 20 J intensity was delivered to the esophagi of 6 dogs. Following sacrifice 72 hours later, no anatomical injury to the esophagi were observed. Atrial defibrillation was then performed in 8 anesthetized and 4 sedated patients using stimulus energies of 15 to 60 J. No adverse symptoms (dysphagia, esophagospasm, etc.) were reported during inquiries conducted over the 2-8 month period following transesophageal defibrillation.

    Transesophageal cardioversion. McKeown PP, Croal S, Allen JD, Anderson J, Adgey AA. Royal Victoria Hospital, Belfast. Am Heart J 1993 Feb;125(2 Pt 1):396-404.With the use of a novel quadripolar esophageal electrode system, we have attempted 131 transesophageal cardioversions in 105 patients: 109 episodes were atrial fibrillation, 16 episodes were atrial flutter, 2 episodes were supraventricular tachycardia, and 4 episodes were ventricular tachycardia. The mean predicted transesophageal impedance (+/- SEM) of 52.6 +/- 1.1 omega was significantly lower than the mean predicted transthoracic impedance (+/- SEM) of 63.1 +/- 1.6 omega (n = 104; p< 0.01). Of the 88 patients who presented with atrial fibrillation as the initial arrhythmia, successful transesophageal cardioversion (maximal delivered transesophageal energy of 100 J in 84 patients and 200 J in 4 patients) was recorded in 70 (79.5%); transesophageal cardioversion required a mean delivered energy of 63.1 +/- 4.2 J and a mean peak current of 20.3 +/- 0.6 A. Transthoracic countershock (maximal delivered energy of 360 J) was attempted in 17 of 18 patients when the transesophageal approach had been unsuccessful; countershock was successful in 10 patients, which yielded an overall success rate of 92.0% (mean successful delivered energy [transesophageal and transthoracic] of 85.3 +/- 7.8 J). All episodes of atrial flutter, supraventricular tachycardia, and ventricular tachycardia were successfully terminated with the use of the esophagus. This esophageal electrode system permits low-energy countershock of atrial and ventricular tachyarrhythmias. 

    CardioCommand notation: One of the 4 patients receiving 200 J shocks reported difficulty in swallowing post-cardioversion; esophagoscopy revealed superficial mucosal damage. Patient symptoms resolved within 72 hours and repeat esophagoscopy showed complete resolution of the injury. One patient defibrillated with 180 J died a week later from an infection; no esophageal damage was noted at autopsy. Elective endoscopy was also performed on 3 patients within 72 hours of transesophageal countershocks of 50-150 J; no evidence of esophageal injury was found.

    Does the change of the polarity of electrodes influence the results of transesophageal bidirectional DC cardioversion? Poleszak K, Kutarski A, Koziara D, Baszak J, Olezcak. University Medical Academy; Lublin, Poland. PACE 21(II):176-180, 1998. The aim of the study was to compared the bidirectional DC cardioversion (BOC) with unidirectional transesophageal DC cardioversion (UOC) and to evaluate if the revirsion of the polarity of electrodes alters the effectiveness and the amount of energy during BOC. UCOC was attempted in 300 patients (pts) with atrial fibrillation (AF) and BOC in 241 pts with AF. In UOC mode, shocks were delivered between a 4-ring esophageal electrode (cathode) and a chest pad (anode) positioned in the precordial region. In BOC, shocks were delivered between the same esophageal electrode and 2 chest pads electrically joined with each other and positioned on both sides of the sternum. First 147 pts were cardioverted with the esophageal electrode as a cathode, next 94 with an anode in esophageal position. The effectiveness of both modes (UOC and BOC) was very high, however in pts with chronic AF success rate was higher in BOC approach (82% vs. 100%). BOC, compared with UOC, allowed a significant decrease in the defibrillation threshold: in pts with recent onset of AF from 61.5 J to 33.3 J, and in pts with chronic AF from 99.8 J to 75.2 J. In pts with long standing AF the reduction of the defibrillation threshold was statistically not significant (68.6 J to 50.6 J). The effectiveness of BOC was also very high independently of the polarity of electrodes. The change of polarity also did not affect the minimal and total successful energy of shocks. In pts with esophageal electrode as a cathode defibrillation threshold was 48.4 J and in pts with the anodal electrode 43.7 J. In conclusion, we found BOC as a very effective cardioversion method in pts with AF. Defibrillation threshold in BOC is lower than in UOC and the polarity of electrodes does not influence the success rate or threshold energy.

    CardioCommand Notation: Poleszak et al. delivered defibrillatory shocks with cumultative energies ranging from 30 J (recent onset of AF) to 250 J (chronic AF). 6% of patients reported difficulty in swallowing, with resolution of symptoms within 24 hours in all 32 of the cases. Following the procedure, esophagoscopy revealed hyperemia and minimal superficial mucosal damage in some of the patients, however no correlation was found between intensity of patient symptoms and extent of injury measured by endoscopy. A second exam performed 7 days post-procedure showed complete resolution of all injuries. 

    Value of esophageal stimulation for decreasing auricular flutter. Moquet B, Cosnay P, Fauchier JP, Rouesnel P, Mannara R, Rioux P, Doll G. Service de Cardiologie B, Hopital Trousseau, Tours. Ann Cardiol Angeiol (Paris) 1988 Feb;37(2):53-9. The purpose of this study was to evaluate the effectiveness of trans-esophageal atrial stimulation in decreasing atrial flutters. 31 patients, aged between 26 and 86 years, underwent 38 esophageal stimulations between August 1986 and April 1987. Esophageal stimulation was carried out with a device delivering major stimuli (10 to 20 ms) as well as high voltages (10 to 20 volts). A bipolar probe of permanent intracardiac stimulation was placed behind the left atrium, via a trans-esophageal approach under ECG guidance. Stimulations were carried out at a slightly faster rhythm than that of the atrial flutter, for 1 to 30 seconds with a progressive increase of the stimulation frequency (280 to 960 impulses/min) until either a sinus rhythm or an atrial fibrillation was obtained. A sinus rhythm was obtained immediately (21 times out of 38; 55.3%) and at the 24th hour after temporary atrial fibrillation in 8 additional patients (21%). The reduction percentage at 24 hours was therefore 76.3 p. cent. In 6 patients (15.8%), esophageal stimulation failed and in 3 additional patients, after atrial fibrillation, there was either relapse into flutter, or persistence of atrial fibrillation at the 24th hour. Esophageal stimulation was well tolerated in all cases. There were no local or rhythm complications. In conclusion, transesophageal atrial stimulation appears to be effective, easy to implement, economical and well tolerated. Its primary use to decrease atrial flutter seems justified, permitting to avoid in 75% of the time, recourse to intracardiac atrial stimulation or external shock.

    Transesophageal rapid stimulation of the left atrium in atrial tachycardias. Sterz H, Prager H, Koller H. Z Kardiol 1978 Feb;67(2):136-8. A new method to interrupt atrial tachycardias is reported. With an esophageal double-electrode the left atrium is stimulated with an external pacemaker at rates of 400 per minute and with 10 to 20 mAmp; The rhythm-disturbances treated in this way were: atrial tachycardias with constant or inconstant blocks and paroxysmal supraventricular tachycardias. 7 of 9 cases reported showed positive results, i.e. electrically induced atrial fibrillation and sinusrhythm immediately or within the first hour after stopping the pacer (6) or atrial fibrillation after disconnection from the pacer at a lower heart-rate than before (1). In 2 cases the technique was applied without success. The transoesophageal rapid left atrial stimulation (oeRLAS) is painless, can be applied without sterile measures and even without X-ray-control just by observing the oesophageal Ecg. Digitalisation is unimportant. The technique described may prove useful in cases of atrial tachycardias esp; in intensive care units.

    Use of transesophageal atrial stimulation in the treatment of atrial flutter. Clinical experience. Disertori M, Inama G, Vergara G, Guarnerio M, Furlanello F. G Ital Cardiol 1984 Mar;14(3):153-7 . Transesophageal atrial pacing with relatively low current output and wide pulse duration has been recently reported. With this method supraventricular tachycardias can be successfully induced and terminated. In this study 23 episodes of spontaneous common atrial flutter (21 patients) were treated by rapid transesophageal atrial pacing (output of 16 Volts and pulse duration of 10 msec). Sinus rhythm resumption was obtained in 18 episodes (78.2%), directly after interruption of stimulation in 7 and following brief periods of atrial fibrillation in 11. All patients tolerated the procedure well with moderate discomfort; no complications were observed. Esophageal pacing offers a useful, rapid, minimally invasive, well tolerated method of terminating atrial flutter in the clinical practice.

    Transesophageal atrial pacing: a first-choice technique in atrial flutter therapy. Guarnerio M, Furlanello F, Del Greco M, Vergara G, Inama G, Disertori M. S. Chiara Hospital, Trento, Italy. Am Heart J 1989 Jun;117(6):1241-52. Here we report on a study of 181 episodes of spontaneous atrial flutter (AF) (mean atrial cycle length 250 +/- 32 msec) treated by transesophageal atrial pacing (TAP) in 138 patients (92 men and 46 women; mean age 59.5 +/- 12.6 years). TAP was effective in 163 episodes (90%); sinus rhythm resumption was immediate in 36 (19.9%) and followed a short period of atrial fibrillation in 64 (35.3%); in 63 episodes (34.8%) a stable atrial fibrillation was obtained. TAP was unsuccessful in 18 cases (10%). All the patients tolerated the procedure well. A statistical elaboration with the Fisher exact test did not evidence a correlation between efficacy and age, sex, atrial cycle length, or underlying heart disease but showed a significant correlation between efficacy and AF duration of less than 1 day (p M 0.05) and absence of antiarrhythmic pharmacologic pretreatment (p < 0.01). These data strongly support the immediate first-choice use of TAP in AF therapy.

    Transesophageal atrial pacing using a pill electrode for the termination of atrial flutter. Falk RH, Werner M. Chest 1987;92(1):110-4. To determine the efficacy of transesophageal rapid atrial pacing with a "pill-electrode" for the termination of atrial flutter, we studied 14 consecutive unselected patients presenting with atrial flutter of various etiologies. The bipolar pill-electrode (interelectrode distance 13 mm) was introduced orally without sedation. Of 14 pacing attempts, atrial capture was obtained in 13 (93 percent), and sustained alteration in rhythm (atrial fibrillation, sinus rhythm or type 2 flutter) in 12 (86 percent). Normal sinus rhythm occurred in six (43 percent), in all of whom it was preceded by transient atrial fibrillation. There was no difference in baseline flutter rates, pacing rates for atrial capture, or duration of flutter between patients reverting to sinus rhythm and those remaining in flutter or converting to atrial fibrillation. Pacing was well tolerated in all but one subject. Thus, esophageal pacing with the pill-electrode was simple to perform, well-tolerated and highly successful for atrial capture in patients with atrial flutter. Although it had a lower success rate than DC cardioversion in producing sinus rhythm, the simplicity of application makes it a useful initial alternative, particularly in patients in whom cardioversion may be hazardous.

    Treatment of atrial flutter and rapid atrial tachycardia with transesophageal atrial pacing. Kaneda S, Inoue T, Fukuzaki H. Kobe University School of Medicine, Japan. Jpn Heart J 1989 Jul;30(4):471-8. Eight patients with atrial flutter (AF) and rapid atrial tachycardia (AT) (5 common AF, 1 uncommon AF and 2 AT) were treated with transesophageal atrial pacing (TEAP). In 5 patients no antiarrhythmic agent was used during this study, and in 3 patients procainamide was administrated intravenously. Conversion to sinus rhythm was successfully achieved in 7 patients (5 common AF and 2 AT). Two patients were converted to sinus rhythm immediately after pacing, and transient atrial fibrillation was induced before conversion to sinus rhythm in 5 patients. TEAP failed to terminate the arrhythmia in 1 patient with uncommon AF. Administration of procainamide reduced the atrial rate in 2 common AF and 1 AT, which were successfully converted to sinus rhythm by TEAP, but induced a rapid ventricular response in 2 patients, one of whom also developed hypotension before conversion. No significant complication due to TEAP was observed in this study. In conclusion, TEAP is a noninvasive method with fewer complications and has nearly the same high efficacy for converting AF and rapid AT to sinus rhythm as DC cardioversion or transvenous atrial pacing.

    Natural history of isolated atrial flutter in infancy. Mendelsohn A, Dick M 2d, Serwer GA. C.S. Mott Children's Hospital, Ann Arbor, MI. J Pediatr 1991 Sep;119(3):386-91. To clarify the natural history of isolated (i.e., without associated congenital cardiac anomalies) atrial flutter in infancy, we reviewed the clinical course in nine patients who were seen with this arrhythmia in the first year of life (range 1 day to 4 months). Atrial flutter was identified by the typical sawtooth pattern in leads II, III, and aVF of the surface electrocardiogram or the pattern of atrial flutter on an atrial electrogram recorded through the esophagus. The mean cycle length of the atrial flutter was 151 msec (atrial rate 397 beats/min). Six of the nine patients had other perinatal problems, such as immune and nonimmune hydrops fetalis (two patients), pneumonia (one patient), anemia (five patients), or low birth weight (one patient). In all patients the rhythm reverted to normal, either spontaneously (two patients), with overdrive pacing (four patients), or after oral digoxin therapy (three patients). No consistent temporal relationship between digoxin administration and conversion was observed; conversion was instantaneous in the four patients who received atrial overdrive pacing. Four patients were discharged receiving digoxin therapy (6 months to 1 year). One patient had supraventricular tachycardia after discharge that was controlled with digoxin. No recurrence of atrial flutter was observed among the nine patients during a mean follow-up of 6.8 years (range 0.2 to 20 years). We conclude that isolated atrial flutter in infancy is rare, has a good prognosis, may be related to transient perinatal events, and often spontaneously converts to normal sinus rhythm; however, when it does not, it will respond to transesophageal pacing. Acute and chronic digoxin therapy is probably unnecessary.

    Termination of spontaneous atrial flutter by transesophageal pacing. Chung DC, Kerr CR, Cooper J. University of British Columbia. Pacing Clin Electrophysiol 1987 Sep;10(5):1147-53. Transesophageal atrial pacing using the constant-rate technique was performed in 26 patients presenting with spontaneous atrial flutter (atrial cycle length between 180 and 270 ms). All but one patient had been treated with one or more antiarrhythmic agents (digoxin, quinidine, procainamide, propranolol, verapamil, diltiazem, and propafenone) within the previous 12 hours. Transesophageal atrial pacing at cycle lengths between 80 and 180 ms was successful in terminating atrial flutter in 22 patients: immediate reversion to sinus rhythm in 16, following transient sinus pause in one, following a brief period of atrial fibrillation in three, and following longer periods of atrial fibrillation in another two. No post-conversion ventricular arrhythmia and no other complications were observed. All patients experienced only a mild burning discomfort during the procedure. It is concluded that atrial pacing via the esophagus is a safe and noninvasive technique of terminating spontaneous atrial flutter. The effectiveness of this technique is comparable to endocardial or epicardial atrial pacing.

    Transesophageal atrial stimulation in 168 patients. Arribada A, Alfaro M, Kuhne W, Valdivia L. Hospital Clinico San Borja-Arriaran. Rev Med Chil 1992 Apr;120(4):383-9. Transesophageal atrial stimulation was performed in 168 patients, 95 males and 73 males, 20 to 81 years of age. The indication for atrial stimulation was the study of some bradyarrhythmia in 109 and ischemic heart disease in 59. An esophageal catheter was introduced through the nose and placed at a spot where a bimodal P wave was obtained. Stimulation was performed using a baby Medtronic stimulator coupled to a Vygon amplifier delivering an output of 30 volt. Sinus node recovery time was measured after 2 to 3 min of stimulation at different rates. Wenckebach and 2:1 A-V block as well as ST deviation were determined. Sick sinus syndrome was diagnosed in 41 cases through altered sinus node recovery time and/or secondary pauses; 35 patients showed Wenckebach rhythm at a stimulation rate over 120 per min; 2: 1 A-V block appeared in 22. Ischemic ST-T changes were produced in 20 subjects. No complications were observed, confirming this approach as a simple and effective way to achieve atrial stimulation for diagnostic purposes.

    The treatment of paroxysmal supraventricular arrhythmias in IHD patients with a high risk of developing complications from the anti-arrhythmic therapy. Andriushchenko OM, Olesin AI. Ter Arkh 1996;68(5):57-60. Antiarrhythmic treatment (AAT) adjusted to the variety of arrhythmia and risk to develop complications was given to 336 patients with ischemic heart disease associated with paroxysms of supraventricular tachycardia (SVT), atrial fibrillation or atrial flutter. In the presence of risk to develop AAT complications, the method of choice for SVT patients is transesophageal pacing and impulse therapy. In the presence of arrhythmic collapse, cardiac asthma and pulmonary edema it is preferable to correct arrhythmia by electric impulse therapy.

    The clinical importance of atrial fibrillation-flutter induced by electric transesophageal stimulation of the heart. Grosu AA, Shevchenko NM, Zhosan SI, Tsurkan SE, Testemitsanu AN. Ter Arkh 1989;61(4):75-8. A study was made of the clinical importance of atrial fibrillation-flutter (AFF) induced by using different modes of left atrium stimulation via the esophagus. Ninety-eight patients were entered into the study including 40 patients with a history of AFF paroxysms, 24 with risk factors of AFF development, and 27 practically normal persons. The stimulation modes applied permitted reproducing stable paroxysms of AFF in 85 percent of the patients with a history of arrhythmias and in none of the normal persons. As for the patients with risk factors, stable paroxysms of AFF could be induced in 33 percent of the cases. The specificity and sensitivity of transesophageal electrophysiologic stimulation (TEES) with the modes applied were 100 and 82 percent, respectively. The investigations have demonstrated that TEES appeared most effective when applied in the mode of an even increase of the frequency of the set pace up to 300 imp/min.

    Transesophageal stimulation of the left cardiac atrium in treatment of atrial flutter. Raczak G; Swiatecka G; Lubinski A; Kubica J; Stanke A. Gdansku. Pol Tyg Lek (Poland), Feb 4-11 1991, 46(6-7) p112-4. Transesophageal stimulation of the left cardiac atrium in the treatment of paroxysmal atrial flutter was assessed. An attempt of such a therapy in paroxysmal atrial flutter involved 20 patients. Cardiac atrium was stimulated with overdrive technique, with single or pair of stimuli and multiple impulses of various frequency and duration. Reversal to sinus rhythm was achieved in 10 patients (in 3 out of them through phase of atrial fibrillation transitory). Results confirm therapeutical value of the transesophageal stimulation of the left cardiac atrium in atrial flutter.

    The transesophageal approach to the heart in electrotherapy of trachycardiac arrhythmias. I. Transesophageal electrostimulation procedure. Volkmann H, Paliege R, Kuhnert H, Meier F, Sauser M. Z Gesamte Inn Med 1981; 36(23):903-8. Transoesophageal electrostimulation techniques were used in 124 cases of different tachycardiac disturbances of rhythm. By means of highly frequent transoesophageal atrial stimulation we succeeded in transformating into sinus rhythm in 46% of the patients with atrial flutter, in 29% of the cases with atrial tachycardias and in 75% of the patients with av-junctional tachycardias. At least atrial fibrillation (with decrease of the ventricular frequency) could be induced in 48% in pre-existing auricular flutter, in 38% in auricular tachycardias and in 15% in av-junctional atrial (partial success of therapy). Sinus tachycardias, atrial fibrillation and ventricular tachycardias could practically not be influenced by highly frequent transoesophageal atrial stimulation. Moreover, for the first time the techniques of the doubled or coupled atrial stimulation, in 2 cases also ventricular stimulations with higher frequency were tested on transoesophageal way and were introduced into the treatment of tachycardiac disturbances of rhythm. The therapeutic results of transoesophageal electrostimulation techniques seem to be comparable entirely with those of intracardiac stimulations, in which cases the non-invasive and uncomplicated techniques are accessible also to institutions without possibilities of heart catheterization.

    The transesophageal approach to the heart in electrotherapy of tachycardia. II. Transesophageal cardioversion by means of direct current shock. Volkmann H, Paliege R, Muller S, Weise C, Kuhnert H. Z Gesamte Inn Med 1981 Dec 15;36(24):951-7. Electric experiments of cardioversion by means of direct current shock using special oesophagus electrodes were performed in 153 cases of various tachycardiac disturbances of rhythm. Here we succeeded in the conversion to the sinus rhythm in 86% of the patients with auricular flutter, in 84% of the cases with auricular fibrillation, in 3 of 4 patients with auricular tachycardias, in 10 patients with AV-junctional tachycardias without exception and in 5 of the 6 cases of ventricular tachycardias. Thus, the rate of an immediate success approximately corresponds to the conventional extrathoracic position of the electrodes. Here the smaller expenditure of energy with the possibility of an electrocardioversion also without anaesthesia as well as the readiness to the immediate electrostimulation in the case of an asystolia after cardioversion represent the essential advantages of the transoesophageal way. Despite the smaller rate of success on account of the smaller possibilities of complication, however, primarily transoesophageal stimulation techniques should be used (with the exception in auricular f), in which cases the use special oesophagus as in their failure following cardioversions by means of direct current shock transoesophageally through the same non-invasive approach. Moreover, the analysis of the oesophageally derivable ECG-potentials may facilitate the differentiation of the preexisting tachycardia.

    Transesophageal cardioversion of resistant atrial arrhythmias. Lukoseviciute AJ, Peculiene IR. Resuscitation 1980; 8(3):159-65. One hundred and thirty five episodes of atrial flutter and atrial fibrillation resistant to transthoracical cardioversion were treated in 127 patients with asynchronized direct current shocks via an esophageal electrode constructed by us. Sinus rhythm was restored in 105 (77.8%) cases. The mean defibrillating voltage was 4.3 kV. Complications were not observed.

    Use of the esophageal electric countershock. Lukoshevichiute AI, Pechiulene IR. Kardiologiia 1978 Apr;18(4):12-20. Transesophageal cardioversion was applied in 277 patients 296 times for arrest of cardiac arrhythmia. Paroxysmal fibrillation and flutter of the atria, and paroxysmal tachycardia were arrested in all cases, chronic atrial fibrillation in 92.4% and chronic irregular atrial flutter in 94.1% of cases. In the group of patients where transthoracic cardioversion at a voltage of 7 kV proved ineffective, the sinus rhythm was restored in 76.5% of cases with atrial fibrillation and 84.2% of cases with irregular atrial flutter when one of the electrodes was introduced into the esophagus. The mean defibrillating voltage in transesophageal cardioversion for chronic atrial fibrillation was by 53.8% lower than that in transthoracic cardioversion. The design of the esophageal electrode proposed provides for the continous recording of the ECG in the esophageal lead for the purpose of determining the optimum position of the electrode and identifying the character of disorders in the cardiac rhythm more precisely.

    Treatment of torsades de pointes with esophageal atrial pacing. Smith MS, Lindsay WC, Flowers NC. Medical College of Georgia. Am J Med 1987 Nov;83(5):971-2.  A 65-year-old woman presented with new onset atrial fibrillation. Medical therapy with digoxin and quinidine was not effective in controlling the arrhythmia. Subsequently, complications developed including a stroke and torsades de pointes. The arrhythmia was successfully controlled by overdrive suppression by esophageal pacing. This case illustrates the usefulness of esophageal pacing and how it may be applied in emergencies when transvenous pacing cannot be readily performed outside the intensive care unit setting.

    Transesophageal atrial pacing in the Wolff-Parkinson-White syndrome. Hartzler GO, Maoloney JD. Mayo Clin Proc 52(9):576-81, 1977. In a patient with Wolff-Parkinson-White syndrome, protracted, disabling tachycardia occurred because of low left lateral accessory pathway refractoriness and rapid retrograde conduction, most likely by a septal pathway. Conventional medications, including intravenously administered lidocaine and procainamide, were ineffective in terminating the tachycardia. Transesophageal atrial pacing easily terminated the recurrent supraventricular tachycardia. 

    Transesophageal rapid stimulation of the left atrium in atrial tachycardias. Sterz H, Prager H, Koller H. Z Kardiol 1978 Feb;67(2):136-8. A new method to interrupt atrial tachycardias is reported. With an esophageal double-electrode the left atrium is stimulated with an external pacemaker at rates of 400 per minute and with 10 to 20 mAmp; The rhythm-disturbances treated in this way were: atrial tachycardias with constant or inconstant blocks and paroxysmal supraventricular tachycardias. 7 of 9 cases reported showed positive results, i.e. electrically induced atrial fibrillation and sinusrhythm immediately or within the first hour after stopping the pacer (6) or atrial fibrillation after disconnection from the pacer at a lower heart-rate than before (1). In 2 cases the technique was applied without success. The transoesophageal rapid left atrial stimulation (oeRLAS) is painless, can be applied without sterile measures and even without X-ray-control just by observing the oesophageal Ecg. Digitalisation is unimportant. The technique described may prove useful in cases of atrial tachycardias esp; in intensive care units. 

    Bedside termination of sustained ventricular tachycardia by transesophageal atrial pacing. Katz A, Knilans TK, Prystowsky EN. (Indiana Heart Inst, Indianapolis). PACE, Vol. 15, June 1992.  Transesophogeal atrial pacing was used to terminate hemodynamically stable sustained monomorphic ventricular tachycardia in two patients. The procedure was performed at the bedside, no anesthesia was required, there were no complications, and one of the patients went home after the procedure was performed. This method should be considered prior to using direct current cardioversion in patients with hemodynamically stable sustained monomorphic ventricular tachycardia.

    Therapeutic value of trans-esophageal electrostimulation in tachycardic arrhythmias. Volkmann H, Dannberg G, Kuhnert H, Heinke M Friedrich-Schiller-Universitat Jena. Z Kardiol 1991 Jun;80(6):382-8. We were able to terminate atrial flutter in 136 of 162 patients by transesophageal rapid atrial stimulation (conversion to sinus rhythm in 75 cases, induction of atrial fibrillation in 61 cases). Atrial tachycardias were interrupted in 17 of 23 patients (sinus rhythm in 11, atrial fibrillation in 6 cases), AV reciprocating resp. AV nodal supraventricular tachycardias were terminated in 32 of 33 patients (sinus rhythm in 28 cases, atrial fibrillation in 4 cases). By transesophageal rapid ventricular and/or atrial pacing, ventricular tachycardias could be terminated in 10 of 15 patients. The success rate of transesophageal pacing is influenced by the type of tachyarrhythmia, by the type of atrial flutter and by the stimulation rate. It is not influenced by the tachycardia's cycle length. Because the success rates are comparable with invasive technique and the procedure is simpler, the non-invasive transesophageal antitachycardia pacing represents a useful method for termination of tachycardic arrhythmias. 

    Termination of atrial flutter using esophageal stimulation. Vainer J, Madle A, Smid J, Brunat J, Topinka I. I. interni klinika FN Plzen. Vnitr Lek 1991 Feb;37(2):141-4. The risk of possible complications in atrial flutter leads to attempts to use all available therapeutic possibilities to eliminate this disorder of the cardiac rhythm. By oesophageal stimulation the sinus rhythm was restored in 40% and a change to atrial fibrillation was achieved in 50% of the patients. The advantages of this method include above all speed and the minimal risk of complications; the disadvantage of the method is the unpleasant sensation when the electrode is inserted and the painful perception of the stimuli. Oesophageal stimulation can be recommended as the method of choice in treatment of atrial flutter.

    Does the change of the polarity of electrodes influence the results of transoesophageal bidirectional DC cardioversion? Poleszak K, Kutarski A, Koziara D, Baszak J, Oleszczak K Department of Cardiology, University Medical Academy, Lublin, Poland. Pacing Clin Electrophysiol 1998 Jan;21(1 Pt 2):176-80. The aim of the study was to compare the bidirectional transoesophageal DC cardioversion (BOC) with unidirectional transoesophageal DC cardioversion (UOC) and to evaluate, if the reversion of the polarity of electrodes alters the effectiveness and the amount of energy during BOC. UOC was attempted in 300 patients (pts) with atrial fibrillation (AF) and BOC in 241 pts with AF. In UOC mode shocks were delivered between the 4-ring oesophageal electrode (cathode) and the chest pad (anode) positioned in the precordial region. In BOC shocks were delivered between the same oesophageal electrode and two chest pads joined with each other, positioned on both sides of the sternum. First 147 pts were cardioverted with the oesophageal electrode as a cathode, next 94 with an anode in oesophageal position. The effectiveness of both modes (UOC and BOC) was very high, however in pts with chronic AF success rate was better in BOC approach (82% vs 100%). BOC, compared with UOC, allowed to decrease the threshold defibrillation significantly: in pts with recent onset of AF from 61.5 J to 33.3 J and in pts with chronic AF from 99.8 J to 75.2 J. In pts with long standing AF the reduction of the defibrillation threshold was statistically not significant (from 68.6 J to 50.6 J). The effectiveness of BOC was also very high independently of the polarity of electrodes. The change of the polarity did not affect the minimal and total successful energy of shocks, too. In pts with oesophageal electrode as a cathode defibrillation threshold was 48.4 J and in pts with the anodal electrode 43.7 J. In conclusions we found BOC as a very effective method in pts with AF. Defibrillation threshold in BOC is lower than in UOC and the polarity of electrodes does not influence the success rate and successful energy.

    Transoesophageal versus transchest DC cardioversion. Cochrane DJ, McEneaney DJ, Anderson JM, Adgey AA. Royal Victoria Hospital, Belfast. Q J Med 1993 Aug;86(8):507-11. Attempted cardioversion via the oesophagus (transoesophageal cardioversion) was compared with the transchest approach (transchest cardioversion) in a randomized trial of 100 consecutive patients with atrial fibrillation. For the transoesophageal group, 30, 50 and 100 J were delivered via an oesophageal electrode with subsequent 200 and 360 J transchest if required. For the transchest group, 50, 100, 200 and 360 J were delivered if required. In the transoesophageal group, 36/50 (72%) of patients cardioverted using the transoesophageal route alone, and in the transchest group, 41/50 (82%) of patients cardioverted (p = NS). First shock success was similar for the transoesophageal and transchest groups: 13/50 (26%) vs. 8/50 (16%) respectively. The mean number of shocks required to achieve successful cardioversion was identical for the transoesophageal and transchest groups (2.6). However, transoesophageal cardioversion was more successful than transchest cardioversion at energies <= 100 J (36/50 [72%], and 17/50 [34%], p < 0.05). Median total energy for successful cardioversion was lower for patients in the transoesophageal group (180 J) than the transchest group (350 J) and mean peak current at successful cardioversion was also lower for patients in the transoesophageal group (21.7 A) than the transchest group (27.3 A) (p < 0.05). No oesophageal complications occurred. Thus, using an oesophageal electrode, cardioversion can be achieved as successfully as using the transchest route. The transoesophageal approach offers a low impedance, and consequently a low-energy pathway for cardioversion

    Transesophageal defibrillation: animal studies and preliminary clinical observations. Cohen TJ, Chin MC, Oliver DG, Scheinman MM, Griffin JC. University of California, San Francisco. Pacing Clin Electrophysiol 1993 Jun;16(6):1285-92. Ventricular fibrillation (VF) that fails to respond to transthoracic defibrillation leaves the clinician with few alternatives. The purpose of this study was to develop a technique of rescue defibrillation by use of transesophageal electrodes. Fourteen anesthetized dogs (20-30 kg) were investigated in this study. Two electrodes (300 mm2) were mounted 8 cm apart on an esophageal probe and inserted approximately 40 cm from the mouth. VF was induced using AC current delivered to the myocardium. Defibrillation was then performed between the distal electrode (anode) and anterior skin patch (cathode). After 15 seconds of induced VF, transesophageal and transthoracic defibrillation thresholds (DFTs) were determined in random order. The esophageal DFT (90 +/- 15 joules) tended to be lower than the transthoracic DFT (115 +/- 35 joules), though this difference was not statistically significant. One dog could not be defibrillated by transthoracic defibrillation but responded to transesophageal defibrillation. Esophageal electrodes were also useful for arrhythmia discrimination and ventricular pacing (pacing threshold of 38 +/- 5 mA at a pulse duration of 2.5 msec). Following transesophageal DFT determination, in ten dogs (total energy of 600 +/- 150 joules), acute esophageal histopathology demonstrated mild to severe focal injury to the mucosa and/or muscular layers. However, esophagi in four chronic dogs (total energy of 470 +/- 110 joules) showed no gross evidence of mucosal damage, perforation, or stricture 4 weeks following defibrillation. Histopathology showed only focal myocyte atrophy and repair. As a last resort, transesophageal defibrillation was performed in the emergency room on four patients with out-of-hospital refractory VF who failed > 6 high energy transthoracic shocks. Transesophageal defibrillation successfully terminated VF in each patient in spite of > 50 mins of cardiac arrest, however none of the patients survived the initial resuscitation. In conclusion, transesophageal defibrillation is as effective as transthoracic defibrillation in a canine model and safe up to a total of 600 Joules. Preliminary clinical trials suggest that this method results in conversion from VF when transthroacic defibrillation fails.  

    Innovative emergency defibrillation methods for refractory ventricular fibrillation in a variety of hospital settings. Cohen TJ. Cornell University Medical College. Am Heart J 1993 Oct;126(4):962-8. This article reviews the ability of innovative rescue defibrillation techniques for the treatment of refractory ventricular fibrillation. These data were obtained in a variety of hospital settings at the University of California, San Francisco, from 1986 to 1992. Innovative rescue defibrillation techniques were applied to 15 patients with refractory ventricular fibrillation having failed > or = 2 high-energy transthoracic shocks in a variety of hospital settings. Intracardiac defibrillation was performed from a right ventricular catheter to a posterior patch in nine patients who had refractory ventricular fibrillation in the course of invasive electrophysiologic testing. Emergency simultaneous transthoracic and epicardial defibrillation was successfully performed with standard paddles placed over the thorax in contact with epicardial patch or pacing lead connectors in two patients in the operating room who underwent implantable cardioverter-defibrillator insertion and failed standard rescue defibrillations. Transesophageal defibrillation was performed in four patients in the emergency department who had a refractory ventricular fibrillation in the field. Intracardiac defibrillation successfully terminated refractory ventricular fibrillation in 9 of 9 patients in the electrophysiology laboratory. Similarly, emergency simultaneous transthoracic and epicardial defibrillation restored sinus rhythm in two patients in the operating room. Transesophageal defibrillation performed after 50 minutes of cardiac arrest successfully terminated ventricular fibrillation in each patient. Thus alternative methods now exist that permit rescue defibrillation in a variety of hospital emergency settings. These techniques are performed with simple-to-use equipment that is compatible with standard defibrillators. 

    Ventricular fibrillation induced by transesophageal stimulation performed for the treatment of atrial flutter. Guaragna RF, Barbato G, Bracchetti D. Ospedale Maggiore, Bologna. G Ital Cardiol 1988 Feb;18(2):160-2. The authors describe a case of ventricular fibrillation occasionally induced by high rate transesophageal pacing, performed to treat an atrial flutter. They conclude that, although this technique is generally safe and well tolerated, it must be performed exclusively where an intensive care can be provided.

    Accidental ventricular fibrillation during transesophageal atrial overdrive. Mainardi MA, Cioppi F, Marconi M, Sermasi S. Cardiologia 1992 Apr;37(4):297-9. Transesophageal atrial overdrive stimulation is a widely used technique for the interruption of atrial flutter and supraventricular tachyarrhythmias. We describe a case of 60 year old man with a previous myocardial infarction, suffering from angina during effort after aortocoronary bypass who presented several episodes of atrial flutter treated with success by transesophageal atrial overdrive stimulation using swallowing electrodes. During the treatment of the last episode of atrial flutter, after a 5 s burst at 300 b/min ventricular fibrillation occurred and was promptly interrupted by DC shock. This is the first case in our experience and probably the first report of ventricular fibrillation induced by swallowing electrodes. Possible mechanisms as pharmacological interactions, accidental ventricular stimulation, etc, are discussed. In conclusion, even though the risk of dangerous arrhythmias is very low, transesophageal atrial overdrive stimulation should be performed by experts in an equipped room.

    The induction of ventricular fibrillation by transesophageal pacing in subjects with atrial flutter and compromised left ventricular functioning. Gallo G, Maggi A, Gei P. Divisione e Cattedra di Cardiologia Spedali Civili, Universita degli Studi di Brescia.G Ital Cardiol 1993 Mar;23(3):279-80. In patients with depressed left ventricular function, the normal precautions during transesophageal atrial pacing may not be sufficient to prevent life threatening arrhythmias. In this article two cases of ventricular fibrillation induced during this technique, aimed at treating atrial flutter, are described.

    Ventricular fibrillation during transesophageal atrial pacing in an infant with Wolff-Parkinson-White syndrome. Kugler JD, Danford DA, Gumbiner CH. University of Nebraska Medical Center. Pediatr Cardiol 1991 Jan;12(1):36-8. A complication of transesophageal atrial pacing in an infant with Wolff-Parkinson-White syndrome (WPW) is reported. A newborn infant born with fetal hydrops had recurrent supraventricular tachycardia (SVT) that required repeated successful conversion by transesophageal atrial pacing. Because of secondary left ventricular dysfunction, digoxin was administered. During repeat transesophageal atrial pacing for recurrent SVT, ventricular fibrillation occurred. Although it is unclear which of several possible contributing factors was responsible for the ventricular fibrillation, recommendations are appropriate to minimize the risk in infants with WPW.

    Ventricular fibrillation induced by transesophageal atrial pacing in hypertrophic cardiomyopathy. Favale S, Di Biase M, Rizzo U, Minafra F, Rizzon P. University of Bari, Italy. Eur Heart J 1987 Aug;8(8):912-6. Sudden death is a rather frequent occurrence in patients with hypertrophic cardiomyopathy, yet the mechanism is uncertain in most cases. We describe a case of an 18 years old patient with a family history of hypertrophic cardiomyopathy and sudden death in whom ventricular fibrillation could be repeatedly induced by means of transesophageal atrial stimulation with 1:1 AV conduction at a rate of 200 beats min-1 and prevented by pharmacological depression of AV node. The not particularly high ventricular rate at which VF occurred could suggest that in hypertrophic cardiomyopathy a major role in favouring VF induction is played by the electrophysiological properties of the myocardium and that sudden death can occur as a consequence of different atrial tachyarrhythmias.

    Transesophageal atrial pacing complications in patients suspected of tachy-brady syndrome. Raczak G, Swiatecka G, Lubinski A, Kubica J. Medical Acadamy of Gdansk, Poland. Pacing Clin Electrophysiol 1990 Dec;13(12 Pt 2):2048-53. The clinical effects of transesophageal atrial pacing (TAP) were assessed in 308 patients. Indications for TAP included evaluation for pacemaker implantation in patients suspected of sinus node dysfunction and determination of the suitable type of pacemaker. Most patients underwent program stimulation including rapid as well as burst stimulation. In one patient, following the study, cerebral arterial embolism occurred, most likely secondary to an induced arrhythmia. That was the only single case of permanent consequences following TAP. Additionally, one patient was accidentally stimulated in the ventricle using low voltage electric current that induced ventricular fibrillation. This was promptly reversed with defibrillation. Twenty-six patients in whom an arrhythmia was previously induced, required medical therapy, two of whom required cardioversion, and 24 required drug therapy, subsequent to clinical intolerance of the arrhythmia. No lethal complications occurred.

    Ventricular fibrillation induced by transesophageal atrial pacing in asymptomatic Wolff-Parkinson-White syndrome. Brembilla-Perrot B, Dechaux JP. CHU de Brabois, Vandoeuvre, France. Am Heart J 1992 Feb;123(2):536-7.

    Transesophageal low-energy cardioversion in an animal model of life-threatening tachyarrhythmias. Yunchang C, Shoulian F, Duanxing G, Shixiang G, Jifent F, Zhushen K, Zhougfan L. Guizhou Provincial Cardiovascular Institute, Republic of China. Circulation 1989 Nov;80(5):1354-9. The purpose of this study was to determine the feasibility and efficacy of terminating life-threatening ventricular tachyarrhythmia by low-energy synchronous or asynchronous shocks delivered through a transesophageal catheter that had both an anode and a cathode. Forty-three episodes of ventricular fibrillation or flutter (Vf or VF) were provoked by transesophageal asynchronous random shocks occurring during the vulnerable period of the ventricular cycle in seven dogs and seven pigs that were healthy adults. The 43 episodes of Vf or VF were terminated by the transesophageal technique. The defibrillation energy thresholds were 23.11 +/- 6.28 Joules (range, 5-30 J). Seven episodes of ventricular tachycardia (VT) with a cycle length of 360 msec or less (330 +/- 27 msec) were provoked by ventricular pacing stimuli during acute myocardial ischemia resulting from delayed resuscitation in two dogs and three pigs. Five of the seven VTs had a duration of 31 seconds or more, and they were all terminated by transesophageal synchronous shocks, the cardioversion thresholds being 1.71 +/- 2.25 J (range, 0.25-5 J). Fourteen episodes of idioventricular tachycardia (IVT) with a cycle length of 400 msec or more (445 +/- 33.5 msec) spontaneously occurred after the use of adrenaline and after defibrillation in four dogs and five pigs. We also succeeded in terminating seven episodes of IVT with a duration of 34 seconds or more by the same means of treating VT, although IVT is not an indication for cardioversion in the clinical setting. The cardioversion thresholds were 1.45 J (range, 0.25-5 J). The difference between the mean energy levels required for cardioversion of VT and IVT were not significant (t=0.2, p >.05). The remaining 2 VTs and IVTs had a duration < 30 secs and were not tested. There was no significant difference of threshold energy of cardioversion for VT or IVT and Vf or VF between dogs and pigs and between animals that weighed > 12.5 kg and < 12.5 kg. There were no apparent functional or histologic ill effects in the esophagi that received cumulative shocks of 100 to 378 Joules. In 246 synchronous or asynchronous shocks (including subthreshold shocks) for cardioversion, acceleration of VT or IVT or degeneration to Vf or VF never occurred. We conclude that this new procedure is a safe and effective method for treating life-threatening ventricular tachyarrhythmias.  

    Transesophageal echocardiography-guided approach to cardioversion of atrial fibrillation. Leung DY, Grimm RA, Klein AL. Cleveland Clinic Foundation. Prog Cardiovasc Dis 1996 Jul-Aug;39(1):21-32. In patients with atrial fibrillation, electrical cardioversion is often performed to relieve symptoms, to improve left ventricular function, and to decrease thromboembolic risks. However, cardioversion of atrial tachyarrhythmias is associated with an increased embolic risk, with an event rate of up to 5.6%. The American College of Chest Physicians recommend 3 weeks of systemic anticoagulation before elective cardioversion and 4 weeks of systemic anticoagulation afterwards. Expulsion of preexisting left atrial (LA) thrombi with resumption of sinus rhythm has traditionally been considered the mechanism for this increased embolic risk associated with cardioversion. The advent of transesophageal echocardiography (TEE) has allowed accurate detection of LA thrombus. Moreover, recent studies using TEE have identified a state of atrial "stunning" immediately after cardioversion, which is considered a thrombogenic milieu in which new thrombus formation and increased or de novo appearance of LA spontaneous echocardiographic contrast have been observed. Furthermore, embolic events have been reported after cardioversion despite exclusion of preexisting LA thrombus by TEE. These studies strongly suggest an alternative mechanism for embolism after cardioversion, ie, atrial stunning with worsened atrial appendage function and enhanced thrombogenesis. Recent studies have shown the safety of a TEE-guided anticoagulation approach in which exclusion of preexisting LA thrombus by TEE enables early cardioversion without the need for the standard 3 weeks of systemic anticoagulation. The importance of maintaining therapeutic anticoagulation has been further emphasized. Although preliminary observational studies of TEE-guided cardioversion are encouraging, there has been no prospective, randomized trial comparing the two strategies of anticoagulation management. The Assessement of Cardioversion Utilizing Transesophageal Echocardiography (ACUTE) pilot study randomized 126 patients from 10 sites and showed the feasibility and safety of the larger scale study. A larger multicenter, prospective randomized trial is now underway and is expected to randomize a total of 3,000 patients. The results of the ACUTE study will definitively establish the safest and the most cost-effective way to manage anticoagulation for elective cardioversion.

    Prevention of embolic events after cardioversion of atrial fibrillation. Current and evolving strategies. Kinch JW, Davidoff R. Evans Meml Dept of Clin Res, Boston (Mass) Univ Med Ctr Hosp. We review the incidence of embolic events following cardioversion of atrial fibrillation, as well as the literature that forms the basis for the current strategy of anticoagulation before, and following, cardioversion to reduce the risk of post-cardioversion embolism. We evaluate a new strategy that uses transesophageal echocardiography to identify patients in atrial fibrillation without atrial thrombi who may be safely cardioverted without preceding anticoagulation and we also address the embolic event and anticoagulation issues in patients with atrial flutter. Cardioversion of atrial fibrillation to sinus rhythm is associated with a small but significant risk of thromboembolic events (average incidence, 1.5%; range, 0% to 7%). Anticoagulating these patients before cardioversion appears to significantly reduce this risk, and because of the delay in return of atrial contraction, anticoagulation should be continued for several weeks following cardioversion. The current guidelines for anticoagulating patients in atrial fibrillation who are to be cardioverted is based primarily on clinical observations, numerous uncontrolled case series, two retrospective trials, and one prospective nonrandomized controlled trial. Anticoagulation for 3 weeks before cardioversion followed by 4 weeks of anticoagulation after cardioversion is a theoretically sound and effective approach to reduce the risk of thromboembolic events. The use of transesophageal echocardiography to rule out thrombus and thus identify low-risk patients who may undergo cardioversion without preceding anticoagulation has been supported by several small studies that successfully used this strategy. However, the demonstration of a postcardioversion atrial and atrial appendage "stunning" suggests that anticoagulation needs to be given at the time of, and following, cardioversion. While promising, this transesophageal echocardiography--guided strategy for cardioversion of patients in atrial fibrillation requires more rigorous study before its routine use can be recommended. The current management of pure atrial flutter requires no anticoagulation before cardioversion; however, several clinical observation suggest theoretical risks for embolic events in these patients, thus further investigation of this strategy may be warranted.

    Thromboembolism following cardioversion of "common" atrial flutter. Risk factors and limitations of transesophageal echocardiography. Mehta D, Baruch L. Mount Sinai Hospital, NY. Chest 1996 Oct;110(4):1001-3. Based on multiple recent studies, anticoagulant therapy is recommended prior to elective cardioversion for patients with atrial fibrillation of more than 24 h duration. The value of anticoagulation in patients with atrial flutter, however, is less well established. Published recommendations for pericardioversion anticoagulation of atrial fibrillation often do not extend to patients with atrial flutter. We evaluated the risk of thromboembolism in our patient population undergoing cardioversion for atrial flutter. Over a period of 30 months, clinically indicated electrical cardioversions were performed in 41 patients with "common" atrial flutter. Sixteen of these patients underwent transesophageal echocardiograms immediately prior to cardioversion to exclude a left atrial thrombus. Three of the 41 patients with atrial flutter developed neurologic ischemic syndromes within 48 h of elective cardioversion. All three patients who developed ischemic neurologic complications had undergone transesophageal echocardiography immediately prior to cardioversion and did not have any evidence of left atrial clot. One patient had cardiomyopathy and the other two had left ventricular hypertrophy. Thus, electrical cardioversion without anticoagulation in patients with atrial flutter and associated heart disease is associated with a risk of thromboembolic events. A normal transesophageal echocardiogram is of doubtful value in prevention of thromboembolic complications.

    Limitations of transesophageal echocardiography in the risk assessment of patients before nonanticoagulated cardioversion from atrial fibrillation and flutter: an analysis of pooled trials. Moreyra E, Finkelhor RS, Cebul RD. MetroHealth Medical Center, Cleveland. Am Heart J 1995 Jan;129(1):71-5. Recent studies have proposed that the exclusion of an atrial thrombus by transesophageal echocardiography (TEE) would allow for the safe cardioversion from atrial fibrillation or flutter without the need of prophylactic anticoagulation. Because all of the TEE trials have been small and descriptive and have lacked randomized, conventionally treated control groups, the pooled risk of embolic events from TEE trials was compared with that of a control group pooled from the literature on cardioversion both with and without conventional anticoagulation. Studies were identified from a MEDLINE search, references in review articles, and recent cardiology abstracts and were included if there were > 10 patients and if atrial fibrillation or flutter was of > 48 hours' duration. Where > 1 study had been published by the same group only the largest study was used. Studies were not selected by cause of arrhythmia, by predisposing risk factors for atrial fibrillation and flutter, or by method of cardioversion. The only patients excluded from TEE reports were those with atrial thrombi diagnosed on the precardioversion TEE or those documented to have adequate standard precardioversion anticoagulation. Seven TEE and 18 control studies met the inclusion criteria. More patients in the control studies had rheumatic valvular disease. Embolic events were significantly more frequent in the TEE group than in the anticoagulated control group (1.34% vs 0.33%, respectively; p = 0.04), whereas there was no significant difference between the TEE group and the nonanticoagulated control group (2.00%; p = 0.26). Thus the use of TEE screening to exclude patients with atrial thrombi before cardioversion does not identify patients who can safely undergo this procedure without anticoagulation.

    Transesophageal echocardiographic detection of atrial thrombi in patients with nonfibrillation atrial tachyarrhythmias and congenital heart disease. Feltes TF, Friedman RA. Texas Children's Hospital, Baylor College of Medicine, Houston 77030. J Am Coll Cardiol 1994 Nov 1;24(5):1365-70. OBJECTIVES. We hypothesized an association between atrial thrombi and nonfibrillation atrial tachyarrhythmias in patients with congenital heart disease. BACKGROUND. We observed a fatal thromboembolus after direct current cardioversion in an adolescent with atrial flutter and repaired tetralogy of Fallot. METHODS. Using transesophageal echocardiography, we prospectively studied 19 consecutive patients with congenital heart disease with nonfibrillation atrial tachyarrhythmia (atrial flutter in 18, primary atrial tachycardia in 1) undergoing electrophysiologic procedures (median age 19.6 years, range 7.0 to 53.8; 11 male, 8 female). Transthoracic echocardiograms were available for 17 patients. RESULTS. All transesophageal examinations were performed without incident. No atrial thrombi were detected in 11 patients who subsequently had uncomplicated direct current cardioversion. Eight solitary atrial thrombi were detected (incidence 42%). Six thrombi were located in the right atrium (Fontan repair in four patients, Ebstein's malformation repair in two), and two were noted in the left atrium (congenital hypertrophic cardiomyopathy and atrial septal defect repair in one patient each). Transthoracic echocardiograms were available in seven of eight patients with thrombus detected by transesophageal echocardiography, with only one study conclusive for an atrial thrombus. Cardioversion was deferred in six of eight patients with thrombus, and anticoagulation therapy was initiated. Uncomplicated electrophysiologic procedures were conducted in two patients at the time of detection of right atrial thrombus (atrioventricular node ablation in one patient, direct current cardioversion in the other). CONCLUSIONS. Prothrombin conditions exist in patients with congenital heart disease with nonfibrillation atrial tachyarrhythmias, as indicated by a significant incidence of transesophageally detected atrial thrombi. The need for prophylactic anticoagulation and the safety of pharmacologic or direct current cardioversion are issues that remain unresolved.

    Left atrial appendage function and thrombus formation in atrial fibrillation-flutter: a transesophageal echocardiographic study. Santiago D, Warshofsky M, Li Mandri G, Di Tullio M, Coromilas J, Reiffel J, Homma S. Columbia-Presbyterian Med Ctr, NY. J. Am Coll Cardiol 1994 Jul;24(1):159-64. OBJECTIVES. The purpose of this study was to investigate left atrial appendage size, function and thrombus prevalence in patients with atrial "fibrillation-flutter." BACKGROUND. Thrombus formation and peripheral embolization in atrial fibrillation are related to left atrial appendage dysfunction. Embolization occurs less frequently in atrial flutter. It is not known whether the atrial appendage in fibrillation-flutter, which has an intermediate appearance on the surface electrocardiogram (ECG), has distinct characteristics that could affect thrombus formation. METHODS. Sixty-one patients with atrial tachyarrhythmias underwent transesophageal echocardiographic examination of the left atrial appendage. Appendage area, peak emptying velocity and the presence of thrombus and spontaneous echo contrast were determined. The results for 14 patients with fibrillation-flutter (based on ECG fibrillatory wave characteristics) were compared with those for 30 patients with atrial fibrillation and 17 patients with atrial flutter. RESULTS. Both fibrillation-flutter and atrial fibrillation were associated with chaotic appendage flow patterns with similarly low peak emptying velocities (18 +/- 8 and 17 +/- 10 cm/s, mean +/- 1 SD, respectively). Atrial flutter was associated with a regular pattern of appendage contraction and a significantly higher peak emptying velocity (42 +/- 18 cm/s, p < 0.0001). Mean appendage area was similar for fibrillation-flutter and fibrillation (6.3 +/- 2.2 and 6.7 +/- 2.1 cm2, respectively) but was significantly smaller for atrial flutter (5.3 +/- 1.4 cm2, p < 0.05). The prevalence of left atrial appendage thrombus was similar for fibrillation-flutter and atrial fibrillation (40% and 29%, respectively), whereas no patient with atrial flutter had a thrombus (p < 0.05). Similarly, the presence of spontaneous echo contrast was higher for fibrillation-flutter (50%) and atrial fibrillation (40%) than for atrial flutter (6%, p < 0.05). CONCLUSIONS. Left atrial appendage size and function in atrial fibrillation-flutter are indistinguishable from those of typical atrial fibrillation, and the frequency of thrombus and spontaneous echo contrast is similarly high. This is in contrast to atrial flutter, which is characterized by a smaller, more contractile left atrial appendage and a lower frequency of thrombus and spontaneous echo contrast.

    Evaluation of transesophageal echocardiography before cardioversion of atrial fibrillation and flutter in nonanticoagulated patients. Black IW, Hopkins AP, Lee LC, Walsh WF. Prince Henry Hospital, Sydney. Am Heart J 1993 Aug;126(2):375-81. This study prospectively evaluated the role of transesophageal echocardiography (TEE) in screening for atrial thrombi before electrical cardioversion in 40 nonanticoagulated patients with nonvalvular atrial fibrillation (n = 33) or atrial flutter (n = 7). Transthoracic echocardiography did not detect atrial thrombus in any patient. TEE detected left atrial appendage thrombi in five patients (12%, p = 0.03), significantly associated with left ventricular systolic dysfunction (p = 0.02) and left atrial spontaneous echo contrast (p = 0.04). Cardioversion was cancelled in the five patients with thrombi and in two patients with spontaneous reversion before planned cardioversion. Cardioversion was successful in 25 (76%) of the 33 remaining patients. Cerebral embolism occurred 24 hours after successful cardioversion in one patient with atrial fibrillation and left ventricular dysfunction, who had left atrial spontaneous echo contrast, but no thrombus was detected by TEE before cardioversion. Repeat TEE after embolism showed a fresh left atrial appendage thrombus and increased left atrial spontaneous echo contrast. These results indicate that TEE improves the detection of left atrial appendage thrombi in candidates for cardioversion, in whom the procedure may be deferred. However, the exclusion by TEE of preexisting atrial thrombi before cardioversion does not eliminate the risk of embolism after cardioversion because of persistent atrial stasis and de novo thrombosis.

    Accuracy of transesophageal echocardiography for identifying left atrial thrombi. A prospective, intraoperative study. Manning WJ, Weintraub RM, Waksmonski CA, Haering JM, Rooney PS, Maslow AD, Johnson RG, Douglas PS. Cardiovascular Division, Beth Israel Hospital, Boston, MA 02215, USA. Ann Intern Med 1995 Dec 1;123(11):817-22 . OBJECTIVE: To determine the ability of transesophageal echocardiography to accurately identify or exclude left atrial thrombi. DESIGN: Prospective cohort study. SETTING: University hospital. PATIENTS: 231 consecutive patients having transesophageal echocardiography before elective repair or replacement of the mitral valve or excision of a left atrial tumor. Fifty-six percent of patients had a history of atrial fibrillation, and 17% had a history of thromboembolism. MEASUREMENT: Identification of left atrial thrombi during transesophageal echocardiographic examination and comparison with direct near-simultaneous visualization during cardiac surgery. RESULTS: Transesophageal echocardiography identified 14 left atrial thrombi in 14 patients (6%). Thrombus size range from 3 to 80 mm. Surgery confirmed 12 of 14 thrombi (86%), including 9 thrombi confined to the left appendage. No additional thrombi were found on direct inspection of the atria (sensitivity, 100% [95% CI, 74% to 100%]; specificity, 99% [CI, 97% to 99.9%]; positive predictive value, 86% [12/14]; negative predictive value, 100% [217/217]; for a population that had a 5.2% prevalence of thrombi). All 12 surgically confirmed thrombi were identified by two independent observers. Neither thrombus seen by only a single observer on transesophageal echocardiography was confirmed during direct inspection of the atria at surgery. CONCLUSION: Transesophageal echocardiography is highly accurate for identifying left atrial thrombi and can be used clinically to exclude left atrial thrombi.

    Echocardiographic parameters for predicting maintenance of sinus rhythm after internal atrial defibrillation. Omran H, Jung W, Schimpf R, MacCarter D, Rabahieh R, Wolpert C, Illien S, Luderitz B. University of Bonn, Germany. Am J Cardiol 1998 Jun 15;81(12):1446-9. Chronic atrial fibrillation (AF), which is refractory to external electrical direct current shock and/or pharmacologic cardioversion, may be successfully cardioverted using internal atrial defibrillation. To avoid unnecessary procedures, it is important to be able to predict which patients will revert to AF. Thirty-eight patients with chronic AF underwent successful internal atrial defibrillation and were followed for 6 months after restoration of sinus rhythm. Left atrial (LA) diameter, left ventricular ejection fraction, maximum LA appendage area, and peak emptying velocities of the LA appendage were analyzed to determine which of these factors were associated with recurrence of AF. Forty-nine percent of patients had a recurrence of AF within 6 months following internal atrial defibrillation. The preprocedural ejection fraction (mean +/- SD 59 + 14% vs 57 + 13%, p = 0.63), LA diameter (4.2 +/- 0.6 cm vs 4.5 +/- 0.6 cm, p = 0.16), and LA appendage area (5.0 +/- 1.5 cm2 vs 5.8 +/- 1.5 cm2, p = 0.13) did not differ significantly between patients who maintained sinus rhythm and those who had recurrence of AF. Peak emptying velocities of the LA appendage before cardioversion were significantly lower in patients with recurrence of AF compared with patients who maintained sinus rhythm (0.26 +/- 0.1 m/s vs 0.49 +/- 0.17 m/s, p = 0.001). A peak emptying velocity <0.36 had a sensitivity of 82% and a specificity of 83% for predicting recurrence of AF.

    Evaluation of left atrial filling using systolic pulmonary venous flow velocity measurements in patients with atrial fibrillation. Oki T, Tabata T, Yamada H, Wakatsuki T, Fukuda K, Abe M, Onose Y, Iuchi A, Fukuda N, Ito S. University of Tokushima, Japan. Clin Cardiol 1998 Mar;21(3):169-74. BACKGROUND: The pattern of pulmonary venous flow velocity is useful for understanding the hemodynamic relationship between the left atrium and left ventricle in patients with a variety of diseases, and the systolic flow wave, in particular, is considered a clinically important parameter that reflects left atrial filling. HYPOTHESIS: The study was undertaken to determine whether systolic pulmonary venous flow velocity patterns can be used to evaluate left atrial filling in patients with atrial fibrillation. METHODS: We performed transesophageal pulsed Doppler echocardiography and cardiac catheterization in 34 patients with chronic atrial fibrillation (10 with hypertrophic cardiomyopathy, 5 with dilated cardiomyopathy, 7 with previous myocardial infarction, and 12 with isolated atrial fibrillation) and 15 normal controls in sinus rhythm. RESULTS: Mean pulmonary capillary wedge pressure, V-wave height in the pulmonary capillary wedge pressure curve, and left ventricular end-diastolic pressure were significantly higher in the hypertrophic cardiomyopathy and dilated failing heart (previous myocardial infarction and dilated cardiomyopathy) groups than in the isolated atrial fibrillation and normal groups. The peak velocity and time-velocity integral of the systolic pulmonary venous flow velocity, and percent left atrial emptying fraction were significantly lower in the dilated failing heart group than in the isolated atrial fibrillation, hypertrophic cardiomyopathy, and normal groups. The peak velocity and time-velocity integral of the systolic pulmonary venous flow velocity, percent left atrial emptying fraction, and V-wave height were comparatively constant when the preceding R-R intervals were relatively stable in the isolated atrial fibrillation group and in 4 of the 10 patients with hypertrophic cardiomyopathy. However, changes in these variables correlated with the preceding R-R interval in all patients with dilated failing hearts and in 6 of the 10 patients with hypertrophic cardiomyopathy. CONCLUSION: Transesophageal pulsed Doppler echocardiographic measurements of systolic pulmonary venous flow velocity are valid indicators of left atrial filling in patients with atrial fibrillation.

    Optimal number of beats for the Doppler measurement of cardiac output in atrial fibrillation. Dubrey SW, Falk RH Boston University School of Medicine. J Am Soc Echocardiogr 1997 Jan-Feb;10(1):67-71. This study was undertaken to determine the optimum number of Doppler velocity waveforms required to calculate cardiac output in atrial fibrillation with the same degree of accuracy as that for sinus rhythm. Twenty-one patients in atrial fibrillation underwent calculations of cardiac output derived from aortic Doppler waveform velocity time integrals and RR intervals. The variability in estimates of the cardiac output was calculated with the successive addition of sequential beats and compared with that determined in a control group of 12 subjects in sinus rhythm. For the group in atrial fibrillation, a mean of 13 beats (range 4 to 17 beats) was required to achieve an estimation of cardiac output with a variability of less than 2%, compared with a mean of four beats in sinus rhythm. In atrial fibrillation, the mean number of beats required to determine cardiac output was approximately three times that necessary in sinus rhythm.

    Right and left ventricular diastolic function in patients with and without heart failure: effect of age, sex, heart rate, and respiration on Doppler-derived measurements. Yu CM, Sanderson JE. Chinese University of Hong Kong, Hong Kong, China. Am Heart J 1997 Sep;134(3):426-34. Doppler echocardiography is widely used to assess right and left ventricular diastolic function. Although the factors affecting Doppler-derived measurements have been described in unaffected patients, there is little information available for patients with heart failure. Therefore we performed two-dimensional Doppler echocardiography studies of right and left ventricular function in 140 subjects, 88 with congestive heart failure and 52 age-matched normal subjects. The separate effects of age, sex, heart rate, and respiration were assessed by correlation analysis and multiple linear regression. In normal subjects both left and right ventricular parameters significantly correlated with age and heart rate. No significant effect of respiration was apparent in left ventricular function, but in the right ventricle inspiration caused a significant increase in transtricuspid peak E-wave velocity, E/A ratio, and shortening of the E-wave deceleration time. There was a significant correlation between left and right ventricular diastolic parameters. In heart failure, age correlated weakly with mitral valve peak A wave (r = 0.23, p = 0.03) and with tricuspid valve peak E-wave velocity (r = 0.37, p < 0.001), although in those with a restrictive filling pattern age was associated with a significant increased shortening of the mitral E-wave deceleration time (r = -0.8; p = 0.0015). Heart rate and deceleration time of mitral and tricuspid E wave significantly correlated, but heart rate did not correlate with either mitral or tricuspid peak E-wave or A-wave velocities or E/A ratio. In heart failure the effect of respiration was similar to normal subjects. Sex was not associated with Doppler variables in either normals or heart failure subjects. Thus this study demonstrates that age, heart rate, and respiration have important and separate associations with Doppler echo diastolic parameters of the right and left ventricle in normal subjects and similar, although weaker relations in patients with heart failure.

    Effect of physiological heart rate changes on left ventricular dimensions and mitral blood flow velocities in the normal fetus. Tsyvian PB, Malkin KV, Wladimiroff JW.Biophysical Laboratory, Mother and Child Care Institute, Yekaterinburg, Russian Federation. Early Hum Dev 1995 Jan 30;40(2):109-14. M-mode echo recordings of the left ventricle (LV) and inflow LV Doppler velocimetry were performed in nine normal fetuses at a gestational age of 36-39 weeks. In each fetus approximately 80 consecutive cardiac cycles were digitized. The duration of each cardiac cycle (T) and the corresponding end-diastolic (EDD), end-systolic (ESD) dimensions of LV or the peak velocity of early (E) and late atrial (A) mitral flow parameters was calculated. The role of sonographic parameters on current (Tn) and preceding (Tn-1) cardiac cycles was assessed using linear regression. Significant dependency of ventricular EDD and transmitral A peak velocity upon Tn was demonstrated. We speculate that atrial systole has an important role to play in the beat-to-beat regulation of fetal stroke volume.

    Left ventricular diastolic parameters in 288 normal subjects from 20 to 80 years old. Mantero A, Gentile F, Gualtierotti C, Azzollini M, Barbier P, Beretta L, Casazza F, Corno R, Giagnoni E, Lippolis A, et al. Department of Cardiology, A. De Gasperis, Ca' Granda Hospital, Niguarda, Milano, Italy. Eur Heart J 1995 Jan;16(1):94-105. Left ventricular diastolic indexes are influenced by several variables. In order to evaluate the relationship of these indexes to age, heart rate, sex and to standard echo parameters, 288 normal subjects aged from 20 to 80 years, divided into six age groups, underwent a two-dimensional colour Doppler examination. Doppler examination was performed from the apical four chamber view to evaluate transmitral flow; isovolumic relaxation time (IVRT) was measured from an apical five chamber view. In order to obtain a sufficient number of subjects for an adequate statistical analysis, seven hospitals were involved in the study. Univariate analysis showed that age influences the peak velocity of the E (r = -0.46) and A waves (r = 0.46), the E/A ratio (peak velocities) (r = -0.69), the A wave integral (r = 0.48) and the E/A integral ratio (r = -0.57), the early and late filling fractions (r = -0.48 and r = 0.51 respectively), and the E wave deceleration (r = -0.43) and deceleration time (r = 0.36). In subjects older than 70 years an inversion of the E/A wave ratio was observed. Multivariate analysis confirmed that age has an important influence on left ventricular diastolic indexes but also demonstrated that heart rate has a significant influence. Sex, ejection fraction (EF), and the dimensions of the mitral annulus and the left ventricular posterior wall had less influence on left ventricular diastolic indexes. The mean values of E and A wave acceleration, deceleration and peak velocity were used to depict left ventricular filling morphology in various age groups for three different heart rate values. The conclusions of the study, are: (1) normal left ventricular diastolic parameters were obtained as mean values at seven different hospitals (2) when evaluating left ventricular diastolic function parameters it is important to take into account age and heart rate; E/A inversion in older subjects should be considered the normal mitral flow pattern.

    Effects of heart rate increase by transesophageal stimulation on the left ventricular filling in the normal subject. A pulsed echo-Doppler study. Roul G, Bareiss P, Facello A, Burggraf C, Rochoux G, Kraenner C, Mossard JM, Sacrez A. hopital de Hautepierre, CHRU de Strasbourg. Arch Mal Coeur Vaiss 1991 Feb;84(2):189-94. The effects of increasing the heart rate on left ventricular filling were studied by Doppler echocardiography in 12 mildly sedated normal subjects. The heart rate was increased by 10, 20 and 30 bpm with respect to the basal rhythm by transoesophageal pacing. Four stages were thereby defined: S0, S1, S2 and S3. The principal results were: absence of variation of the isovolumic relaxation period in absolute values (92 +/- 14, 86 +/- 16, 87 +/- 16, 78 +/- 11 ms); absence of variation of the duration of the rapid filling period (246 +/- 36 at 50 vs 220 +/- 28 ms at 53); no change in peak filling velocity (72 +/- 11 at 50 vs 61 +/- 11 ms at 53) or in the timing of peak velocity (77 +/- 12 at 50 vs 72 +/- 13 ms at 53); increased contribution of atrial systole during tachycardia (Vmax 43 +/- 7 at 50 vs 76 +/- 17 cm/s at 53). Therefore, of these Doppler echo parameters, only atrial systole changed during the range of tachycardia rates which were studied. Its increase compensated the loss of diastolic diastasis. These changes should be born in mind in Doppler echocardiographic studies of left ventricular diastolic function.

    Observations on induction and termination of paroxysmal supraventricular tachycardia by external pacing. Grubb BP, Markel ML, Artman SE, Post WR, Luck JC. Department of Medicine, Pennsylvania State University, University Hospital, Hershey. Pacing Clin Electrophysiol 1992 Nov;15(11 Pt 2):1944-52. Paroxysmal supraventricular tachycardia (PSVT) can be reproducibly induced and terminated by critically timed atrial or ventricular depolarizations. In this study, noninvasive transcutaneous (external) cardiac pacing (NTCP) was compared to endocardial ventricular pacing for the termination and induction of PSVT. In 24 patients, either atrioventricular (AV) nodal reentrant tachycardia or AV reciprocating tachycardia was reproducibly terminated with either critically timed ventricular depolarizations or overdrive ventricular pacing from an endocardial right ventricular site. There were 32 trials of NTCP attempts to interrupt PSVT in the 24 patients. External pacing was successful at terminating PSVT in 23 patients and in 30 of 32 (94%) trials. In 20 patients, there were 26 trials of external pacing attempts to induce PSVT. External pacing initiated PSVT in 21 of 26 trials (81%). The pacing sequences used to induce and terminate PSVT with external pacing were copied from the endocardial sequences. The external pacing threshold averaged 77 +/- 22 mA but the current needed to terminate PSVT was about 1.5 greater than threshold at 117 +/- 27 mA. Serial external pacing studies were performed in seven patients. The thresholds for external pacing were similar from trial to trial as were the mode of termination and induction between the endocardial and external methods. External pacing can terminate most AV reciprocating tachycardias and many AV nodal reentrant tachycardias. It appears promising as a means of inducing PSVT. However, the high stimulation amplitudes needed will prohibit wide acceptance of external pacing for induction and termination of PSVT.