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.