Temporal Occurrence of Arrhythmic Complications After Alcohol Septal Ablation

Background: The temporal occurrence of arrhythmic complications after alcohol septal ablation (ASA) is unclear. As a result, the appropriate time to monitor patients after ASA is controversial. The purpose of this study is to determine the temporal occurrence of complete heart block (CHB) and ventricular tachyarrhythmia (VT) after ASA to better understand when patients can be safely discharged. Methods: Consecutive patients treated with ASA for hypertrophic cardiomyopathy from 2003 to 2019 at a tertiary referral center were reviewed retrospectively. The incidence and timing of CHB or sustained VT within 30 days post-ASA were assessed. Results: A total of 243 patients were included in this study. Mean maximal septal thickness was 19.0±3.9 mm, and total volume of ethanol injected was 1.7±0.6 mL. CHB occurred in 59 (24.3%) patients, including transient CHB in 33 (13.6%) and permanent in 26 (10.7%). The initial episode of CHB occurred within 24 hours post-ASA in 51 (21.0%) patients, between 24 and 48 hours in 3 (1.2%), between 48 and 72 hours in 3 (1.2%), and after 72 hours in 2 (0.8%). New permanent pacemaker was placed in 46 (18.3%). Presence of baseline bundle branch block and age ≥70 were significantly associated with CHB but not CHB presenting after 24 hours. VT occurred in 3 (1.2%) patients, including 1 (0.4%) within 24 hours, 1 (0.4%) between 24 and 48 hours, and 1 (0.4%) after 72 hours. VT required cardioversion in 2 patients and new implantable cardioverter-defibrillator placement in 2. Conclusions: The incidence of CHB or VT presenting after 72 hours post-ASA was low. These findings suggest that timely discharge of patients without evidence of early conduction disturbances after ASA can be considered as a potentially safe management strategy, especially in patients without preexisting conduction abnormalities.