Pacemaker dependency in patients undergoing implantation of dual-chamber devices after alcohol septum ablation: a retrospective analysis

Background Patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing alcohol septal ablation (ASA) are at risk for high-degree atrioventricular (AV) block, often requiring permanent pacemaker (PPM) implantation. However, long-term pacemaker dependency in this population remains unclear. Methods We retrospectively analyzed HOCM patients who underwent ASA and subsequent implantation of a cardiac implantable electronic device (CIED) due to procedure-related AV block between 2016 and 2023. CIED interrogation at ≥6 weeks post-implantation was used to assess ventricular pacing (VP). Pacemaker dependency was defined as >1% VP. Associations with baseline characteristics were examined using logistic regression. Results Of 464 patients undergoing ASA, 95 (20.5%) received a CIED, and 67 were available for follow-up. Only 30 patients (44.8%) showed >1% VP; 9 (13.4%) were completely dependent (100% VP). In contrast, 31 patients (46.3%) had ≤0.1% VP. Persistent AV block was more common in patients with pre-interventional left bundle branch block. Intraprocedural AV block showed a trend toward persistent pacemaker dependency. Conclusions In this cohort, long-term pacemaker dependency after ASA was unexpectedly low. These findings suggest that AV conduction may recover in a significant proportion of patients, raising the question of whether some may safely avoid PPM implantation. Larger prospective studies are needed to guide device therapy decisions in this population. Our findings challenge the assumption of permanent AV block after ASA and suggest reconsidering routine early device implantation in selected patients.