Abstract 11477: Assessing New Onset of Atrial Arrhythmia in Patients Undergoing Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy

Abstract

Introduction: Alcohol septal ablation (ASA) is an effective percutaneous procedure used to treat refractory hypertrophic obstructive cardiomyopathy (HOCM). ASA relieves left ventricular outflow tract (LVOT) obstruction by creating a targeted infarction in the septal muscle. Diastolic dysfunction and mitral regurgitation are responsible for increased left atrial pressure which contributes to left atrial ectopy. We seek to assess the incidence of atrial arrhythmias post-ASA and identify predictors to risk stratify these patients. Methods: Using a patient database maintained internally, 144 consecutive patients who underwent ASA for HOCM between March 2017 and February of 2022 at MUSC were retrospectively reviewed. Patients were selected based on the need for cardiac event monitoring after ASA. Patients were retrospectively analyzed for a previous history of atrial fibrillation (AF) as well as a new onset of AF after ASA. SPSS statistics was used for statistical analysis. Results: A total of 31 patients met final inclusion criteria. During the monitored time, seven patients (22.58%) developed a new onset of AF after ASA. Patients who developed AF post-ASA were found to have a statistically higher left atrial end-systolic volume index (LAESVi, mL/m 2 ) and left ventricular end-diastolic pressure (LVEDP, mmHg) (59.96 ± 8.93, 34.33 ± 11.54) when compared to those who did not develop AF (41.13 ± 13.93, 23.33 ± 9.06 (p=0.0003, p=0.0331)). Conclusions: In this high-risk proportion of patients who required cardiac monitoring post-ASA, there is a higher-than-expected risk for new onset of AF. The left atrial size and left ventricular filling pressures before ablation were the only significant predictors for development of atrial arrhythmias after ASA. Longer-term evaluation will be able to address if the expected reduction in atrial size and LVOT gradient after ASA will reduce the overall long-term burden of atrial arrhythmias.