Long-term adherence to flecainide as a rhythm control therapy in recurrent atrial fibrillation - a retrospective cohort study.

Background. Flecainide is a first-line rhythm control treatment for patients with atrial fibrillation (AF), however long-term treatment outcomes are understudied. Objective. To investigate associations of electro- (ECG) and echocardiographic indices with safety and efficacy outcomes of long-term flecainide treatment for recurrent AF. Methods. Consecutive patients with AF admitted for in-hospital flecainide initiation over a 5-year period were retrospectively included (n = 130, age 60 ± 12 years, 65% males, 29% with persistent AF). Baseline ECGs were processed using the 12SL algorithm. P-wave duration (PWD), Deep terminal negativity of the P-wave in lead V1 (DTNP-V1), left atrial volume index (LAVI), valvular dysfunction and right ventricular fractional area change (RV-FAC) were assessed. The primary endpoint was flecainide discontinuation for any reason. Secondary endpoints were discontinuation due to rhythm control failure and rhythm-related adverse events. Results. After hospital discharge, 120 patients were followed for a median of 1.5 years (interquartile range 0.34-3.1). During follow-up 31% discontinued flecainide, 14% due to rhythm control failure and 10% due to rhythm-related adverse events. Flecainide discontinuation was associated with PWD ≥130 ms (HR 3.65, [1.36-9.75]), DTNP-V1 > 0.1 mV (HR 3.78, [1.15-12.4]), LAVI >48 ml/m² (HR 4.43, [2.02-9.70]), moderate mitral regurgitation (HR 4.40, [1.57-12.4]), and RV-FAC <35% (HR 2.30, [1.03-5.16]). Rhythm control failure was associated with PWD, DTNP-V1, LAVI and moderate mitral regurgitation. Rhythm-related adverse events were associated with RV-FAC, LAVI and moderate mitral regurgitation. Conclusion. ECG and echocardiographic indices were associated with discontinuation of flecainide, including safety and efficacy outcomes in long-term treated patients with AF.