Continuous rhythm monitoring for ventricular arrhythmias after alcohol septal ablation for hypertrophic cardiomyopathy

OBJECTIVE: The purpose of the present study was to determine the incidence of ventricular arrhythmias before and after alcohol septal ablation (ASA). BACKGROUND: In patients with hypertrophic obstructive cardiomyopathy (HOCM), gradient reduction by ASA is an alternative for surgical myectomy. However, concerns exist about whether the induction of a myocardial scar during ASA may create substrate for ventricular arrhythmias. METHODS: The study group consisted of 44 patients in whom ASA was performed for symptomatic, drug-refractory hypertrophic cardiomyopathy. Continuous rhythm monitoring was obtained by implantable loop recorder (n=30) or pacemaker (n=14). Occurrence of ventricular and supraventricular arrhythmias before and after ASA was noted, retrospectively. RESULTS: The ASA procedure was considered successful (resting gradient <30 mm Hg, and provoked gradient <50 mm Hg at 4 months in combination with NYHA Class functional status ≤2) in 30 (68%) patients. Rhythm monitoring before ASA was available in 28 patients. The median duration of rhythm monitoring after ASA was 3.0 years (IQR 1.3-4.3). Sustained VT/VF within 30 days after ASA occurred in three patients (7%), including 2 cases of procedural VF, while no VT/VF was observed before ASA (p=0.10). No sustained VT/VF was observed >30 days after ASA. No cardiac deaths occurred during follow-up. CONCLUSIONS: In a low-risk cohort of patients who underwent ASA, in which continuous rhythm monitoring was performed, sustained VT or VF within 30 days occurred in 3 patients (7%) while no VT/VF was observed before ASA. During long-term follow-up, no sustained VT or VF was observed >30 days after ASA.