Flecainide Reduces Ventricular Arrhythmias in Patients With Genotype RyR2-positive Catecholaminergic Polymorphic Ventricular Tachycardia.

INTRODUCTION AND OBJECTIVES: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited disease characterized by polymorphic or bidirectional ventricular arrhythmias (VA) triggered by physical or emotional stress in young people with a structurally normal heart. Beta-blockers are the cornerstone of treatment, while flecainide has recently been incorporated into the therapeutic arsenal. The aim of this study was to report our experience with this drug. METHODS: The cohort included 174 genotype-positive CPVT-patients from 7 families. We collected data from patients who were receiving flecainide and analyzed the indications, adverse effects and dosage, clinical events, VA and arrhythmic window during exercise testing, and implantable cardioverter-defibrillator (ICD) shocks during follow-up. RESULTS: Eighteen patients (10.4%) received flecainide; 17 patients in combination with beta-blockers, and 1 patient as monotherapy due to beta-blocker intolerance. None of the patients presented side effects. In 13 patients (72.2%) the indication was the persistence of exercise-induced VA and in 5 patients (27.7%) persistent ICD-shocks, despite on beta-blockers. After flecainide initiation, the exercise-induced VA quantitative score was reduced by more than 50% in 66.7% of the members of family 1 (32.76 ± 84.06 vs 74.38 ± 153.86; P = .018). The arrhythmic window was reduced (5.8 ± 11.9 bpm vs 19.69 ± 21.27 bpm; P = .007), and 4 of 5 patients with appropriate ICD shocks experienced no further shocks in the follow-up. CONCLUSIONS: In CPVT-patients flecainide reduces clinical events, exercise-induced VA, the arrhythmic window, and ICD shocks, with good tolerance.