High Prevalence of Proarrhythmic Events in Patients With History of Atrial Fibrillation Undergoing a Rhythm Control Strategy: A Retrospective Study.

Background: A retrospective study was undertaken to evaluate the respective prevalence of proarrhythmic events depending on various therapeutic regimens within a population of patients with history of atrial fibrillation (AF) undergoing a rhythm control strategy.

Methods: Inclusion criterion was the presence of AF in the patient's clinical history, whose cardioversion had been followed by the adoption of rhythm control strategy. The primary endpoint was the determination of the respective prevalences of paradoxical arrhythmias in the various therapeutic groups. The secondary objective was all-cause mortality.

Results: A total of 182 cases of proarrhythmia out of 624 patients were detected during a median follow-up of 20 months (interquartile range: 18 - 24 months). The prevalences of proarrhythmic events were: IC antiarrhythmic drugs + beta-blockers, 111 cases out of a total of 251 patients (44.22%); amiodarone, seven cases out of a total of 230 patients (3%); sotalol, 61 cases out of a total of 140 patients (43.57%); quinidine + digoxin, three cases out of a total of three patients (100%). The paradoxical arrhythmias were: torsades de pointes, second- and third-degree sino-atrial block, slow atrial flutter with 1:1 atrioventricular (AV) conduction, second-degree Mobitz II AV block, and sustained monomorphic ventricular tachycardia. No fatal case of proarrhythmia was found.

Conclusions: Secondary prevention of AF relapses by means of drugs suitable for accomplishing rhythm control strategy exposes the patients to incumbent risk of proarrhythmic events. Thus, the choice to avoid some varieties of antiarrhythmics with marked proarrhythmic potential (class IC drugs, sotalol, quinidine) appears to be warranted.