Comparison of antiarrhythmics used in patients with paroxysmal atrial fibrillation: Subanalysis of J-RHYTHM study

Background: The J-RHYTHM (Japanese Rhythm Management Trial for Atrial Fibrillation) study demonstrated the benefit of rhythm-control compared with rate-control in Japanese patients with paroxysmal atrial fibrillation (AF), according to AF-specific quality of life scores. However, detailed information on prescribed antiarrhythmic agents remains unclear. Methods and Results: Data for 419 patients enrolled in the rhythm-control arm of J-RHYTHM were analyzed. The primary endpoint was defined as a composite of total mortality, cerebral infarction, embolism, bleeding, heart failure, and physical/psychological disability. The secondary endpoint was recurrence of AF. The clinical outcome according to choice of initial antiarrhythmic agent (AA) was assessed by Kaplan-Meier survival curve, and further adjusted by Cox-regression hazard model. The primary endpoint occurred in 16.9%, 6.7%, 15.8% and 23.3% of patients assigned to class Ia, Ib, Ic and III agents (P=0.359). The rate of AF recurrence was significantly higher in patients taking a class III drug (Ia, Ib, Ic, III=20.3, 23.3, 29.1, 50.0%; P=0.002). However, after adjustment for other clinical variables, the choice of AA was not associated with recurrence of AF (class I vs III, P=0.15). Conclusions: The incidence of each endpoint did not differ according to the choice of AA. The class III drugs seemed to lower the sinus rhythm maintenance rate, which might be confounded by other comorbid conditions.