De Sisti A, Matteucci C, Patrissi T, Accogli S, Di Lorenzo M, Sasdelli M, Ciolli A, Lo Sardo G, Palamara A Divisione di Cardiologia, Ospedale Sandro Pertini, Roma. G Ital Cardiol 1998 Dec;28(12):1391-9. BACKGROUND: The management of patients with paroxysmal atrial fibrillation (AF) is unsuccessful, because AF recurs in about 50% of patients despite an antiarrhythmic treatment. Usefulness of non-pharmacological strategies is available in a limited subset of patients and it does not present a global solution to the problem. At present, treatment with antiarrhythmic agents is the only available tool in patients with AF recurrence. The aim of this study was to assess the predictive value of the electropharmacological transesophageal (TE) test in the management of patients with paroxysmal AF treated by flecainide. METHODS: In 32 patients, ranging in age from 38 to 70 years (mean: 59 +/- 12 years), with documented episodes of paroxysmal AF (mean: 5.6 +/- 3.7 episodes/last year), we performed an electrophysiological transesophageal (TE) test following pharmacological wash-out. An aggressive protocol was used: step A: 10 sec atrial burst at Wenckebach point + 10 bpm, 200 and 250 bpm; step B: 10 sec atrial bursts at 300, 400, 500 and 600 bpm; step C: 8 sec increasing rate burst from 200 to 800 bpm. Induction of sustained AF (> 1 min) was considered the end-point. Patients were treated with flecainide 100 mg bid and a second TE test was performed at the steady-state, with an identical induction protocol and end-point. Based on the response of the second test, patients were divided into responders (R Group: non-inducible AF) and non-responders (NR Group: inducible, sustained AF). Patients were followed-up by periodical controls and contacted by telephone to confirm their clinical status. RESULTS: Sustained AF was induced in 30 patients (94%) at the first TE study. Eight of them dropped-out at the time of the second TE test (6 patients for lack of consent, 1 patient for side-effects and another one for proarrhythmic effects). In the mean follow-up of 15 +/- 6 months, among patients who underwent a second TE test, AF recurrence was documented in 2 out of 14 patients from the R Group and in 7 out of 10 patients from the NR Group (p < 0.01). There were 4 AF episodes in the R Group and 19 in the NR Group (p < 0.001). We did not find significant statistical differences between the two groups in terms of age, sex, body weight, AF episodes/past year, P-wave duration, left atrial dimension, structural heart disease, AF duration at the first TE test and follow-up duration. In five patients from the NR Group with induced AF lasting > 5 min, the percentage of recurrence was 100% and there were 16 AF episodes. Global percentage of patients with recurrence was 37%. CONCLUSIONS: Flecainide is effective in reducing the incidence of AF and results are similar to other antiarrhythmic agents generally used. The electropharmacological TE test might be a useful tool to predict the response to an antiarrhythmic treatment.