Septal Myectomy Results in Regression of Left Ventricular Hypertrophy in Patients With Hypertrophic Obstructive Cardiomyopathy

Background Hypertrophic cardiomyopathy (HCM) is a genetic disorder characterized by ventricular hypertrophy that occurs in the absence of predisposing cardiovascular stimuli; approximately one quarter of patients with HCM will have left ventricular (LV) outflow tract obstruction. Transaortic septal myectomy relieves outflow gradients and improves symptoms, but the effect of operation on ventricular hypertrophy is not well defined. Methods We reviewed 60 patients who underwent septal myectomy for obstructive HCM; all had complete two-dimensional and Doppler studies including calculation of LV mass and LV mass index before operation and after dismissal. Results Before myectomy the mean LV outflow gradient was 67 ± 44 mm Hg, and at dismissal the mean LV outflow gradient was 12 ± 13 mm Hg (p< 0.004). We found a significant decrease in the LV mass and LV mass index that occurred early after operation and persisted beyond 2 years follow-up. The early decrease in LV mass was greatest in patients younger than 50 years, but patients of all ages benefited from extended septal myectomy with decrease in LV hypertrophy. Conclusions Transaortic septal myectomy results in significant decreases in LV mass and LV mass index. This favorable remodeling occurs early after operation and persists beyond 2 years. Whether the regression of LV mass continues to decrease or stabilize over time is unclear.