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.