Effectiveness of Alcohol Septal Ablation Versus Transaortic Extended Myectomy in Hypertrophic Cardiomyopathy with Midventricular Obstruction

Investigate the effectiveness of alcohol septal ablation (ASA) and transaortic extended myectomy (TEM) in hypertrophic cardiomyopathy (HCM) with midventricular obstruction (MVO).MVO is less common than subaortic obstruction. Data on the effectiveness of ASA and TEM in MVO are lacking.The clinical profiles of 22 patients undergoing ASA and 37 patients undergoing TEM were compared. No patient had apical aneurysm, abnormal chordae, mitral valve replacement or repair.Baseline midventricular pressure gradient and symptoms were comparable between the ASA and TEM groups. During follow-up, both groups demonstrated substantial reduction in pressure gradient (the ASA group: 79.7 ± 21.2 mm Hg to 43.7 ± 28.9 mm Hg, P < 0.001; the TEM group: 69.0 ± 23.9 mm Hg to 15.0 ± 16.9 mm Hg, P < 0.001). The reduction in pressure gradient was greater (78.9 ± 18.6% vs. 46.4 ± 33.4%, P < 0.001) and the residual pressure gradient was lower after TEM versus ASA (P < 0.001). Patients with New York Heart Association class III/IV dyspnea decreased from 59.1 to 18.2% (P = 0.022) in the ASA group and from 56.8 to 5.6% (P < 0.001) in the TEM group. Patients with Canadian Cardiovascular Society class III/IV angina decreased from 40.9 to 9.1% (P = 0.016) in the ASA group and from 32.4 to 0% (P < 0.001) in the TEM group.While ASA and TEM both improve gradients and symptoms, TEM may provide a more reliable reduction in gradients compared to ASA.