Surgical Septal Myectomy for the Treatment of Residual Left Ventricular Outflow Tract Obstruction Following Failed Alcohol Septal Ablation.

The reasons of residual left ventricular outflow tract (LVOT) obstruction following alcohol septal ablation (ASA) remain unclear, and outcomes of myectomy following failed ASA remain underreported.Thirteen symptomatic patients (10 women, a median age of 60.0 years) who underwent septal myectomy following failed ASA were reviewed. The patients were followed up for a median of 6 months. The clinical characteristics and outcomes of these patients were analyzed and were compared with those of 178 patients who underwent isolated myectomy without previous ASA at our institution during the same period.In the first ASA procedure, the median number of septal perforator arteries injected was 1.0 with the median value of peak creatine kinase following ablation of 978.5 U/L.Uncontrollable extent and location of infarcted myocardium caused by ablation and mitral subvalvular anomalies were found in four (30.8%) and seven (53.8%) patients, respectively. No operative or follow-up deaths occurred. The median maximum LVOT gradients fell from preoperative 112.0 to 8.5 mmHg at follow-up (P < 0.001). Compared with controls, patients with failed ASA had a higher proportion of mitral subvalvular anomalies (53.8% versus 13.5%, P = 0.001) and developed a higher incidence of complete atrioventricular block following myectomy (15.4% versus 1.7%, P = 0.038).Low institutional or operator experience with ablation, uncontrollable extent and location of infarcted myocardium caused by ablation, and mitral subvalvular anomalies may be reasons for failed ASA. Surgical myectomy for the treatment of residual LVOT obstruction after unsuccessful ASA may be associated with favorable results.