BACKGROUND Antiarrhythmic therapy for recurrent ventricular arrhythmias in patients who have undergone catheter ablation, and in whom amiodarone and/or beta-blockers were ineffective or contraindicated, is a controversial issue.OBJECTIVE The present study sought to evaluate the efficacy and tolerability of oral procainamide in patients with recurrent ventricular arrhythmias when the standard therapy strategy had failed.METHODS All patients treated with procainamide for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in our institution between January 2010 and May 2019 were enrolled. The primary endpoint was the total number of implantable cardioverter-defibrillator (ICD) interventions after the beginning of procainamide therapy. Secondary endpoints were the total number of VTs and VFs recorded on the ICDs' controls and discontinuation of therapy. The events occurring during procainamide treatment were compared with a matched-duration period before the initiation of therapy with procainamide. Patients therefore served as self-controls.RESULTS A total of 34 consecutive patients (32 male, 94.1%; mean age 74.4 6 9.7 years) were included in the retrospective analysis. The mean time of procainamide treatment was 12.9 6 13.7 months (median 9 [2-20] months). The mean dose of procainamide was 1207 6 487 mg/day. Procainamide therapy significantly decreased ICD interventions (median 5 [0-22.5] vs 15.5 [3-32.25], P , .05). Procainamide also decreased the total number of VT/VF episodes (median 5.5 [0.75-30] vs 19 [7.5-30], P , .05). Only 3 patients (8.8%) presented severe side effects (dyspnea or hypotension), requiring discontinuation of therapy.CONCLUSION Oral procainamide was associated with a significant decrease in ICD therapies and ventricular arrhythmias, showing an acceptable profile of tolerability.

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Background To date, the prognostic impact of transcatheter ablation (T–Abl) of supraventricular arrhythmias (SA) in HCM patients has not been satisfactorily elucidated. Objectives To assess the impact of T–Abl on clinical outcomes in a large cohort of HCM patients. Methods In this retrospective multicenter study, 570 consecutive HCM patients with SA were enrolled, 425 receiving medical therapy and 145 undergoing T–Abl. 1:1 propensity score matching (PSM) led to the inclusion of 234 patients (117 intervention group, 117 medical group) in the final analysis for endpoint evaluation. The primary outcome was a composite of all–cause mortality, heart transplantation (HT) and worsening heart failure (HF). Additionally, an inverse probability weighted (IPW) model was elaborated. Results At PSM analysis, after a median follow-up of 57.3 months, the primary endpoint occurred in 31 (26.5%) patients in the intervention group vs 38 (32.5%) in the medical group (p=0.871). Thromboembolic strokes and major arrhythmic events in the intervention vs the medical group were 9.4% vs 9.4% (p=0.367) and 5.1 vs 7.7% (p=0.741), respectively. Fewer patients in the intervention vs medical group experienced SA recurrences (64.1% vs 84.6%, p<0.001) and transition to permanent SA patterns (21.4% vs 37.6%, p=0.007). IPW analysis showed consistent results. Severe complications related to T–Abl were uncommon (0.7%). Conclusions At 5–year follow–up, T–Abl does not improve major clinical outcomes in a large cohort of HCM patients. Nevertheless, T–Abl seems to facilitate the maintenance of sinus rhythm and decelerate the progression to permanent SA. Lastly, T–Abl is usually safe in HCM.