Abstract 654: Ventricular Arrhythmia Following Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy: Clinical Predictors of Events
Alcohol septal ablation (ASA) is a non-surgical alternative to septal myectomy for treatment of symptomatic, drug refractory hypertrophic obstructive cardiomyopathy (HOCM). The effect of ASA on the risk of ventricular arrhythmia (VA) is unknown. There is a theoretic concern for pro-arrhythmia at the site of myocardial injury. We examined the rates of sudden cardiac death (SCD) and VA (defined as VA requiring ICD therapy or documented VT/VF) among all 88 patients treated with ASA at Massachusetts General Hospital between 1998 and 2004. Of these patients, 37 had either an ICD or a permanent pacemaker in situ that enabled surveillance for VA events. Patients were classified as either high-risk (one of the following: VA or positive EP study, syncope due to suspected VA, family history of SCD, septal thickness ≥30mm by echocardiography, or failure to augment sBP >20mmHg on stress testing), or low-risk (no high-risk features). There was no mortality attributable to sudden cardiac death (mean follow up 35±21mo). The event rate for VA in low-risk patients was 3.0% per year (2/18 patients), and 6.3% annually among high-risk patients (4/16 patients). Device data were not available on three patients. In a stepwise Cox proportional hazards multivariate analysis that included pre-ASA arrhythmia, peri-ASA arrhythmia, pre-ASA gradient, change in gradient after ASA, peak CK-MB, and post-ASA gradient, only post-ASA gradient predicted future VA (HR 1.06, 95% CI 1.03–1.10, p <0.001). In this single center experience, ASA was not associated with SCD or with high rates of VA. The post-ASA gradient correlates with the risk of ventricular arrhythmia after ASA.