Regression of left ventricular hypertrophy after nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy

Backgromtd-Hypertrophic obstructive cardiomyopathy (HOCM) is characterized by left ventricular hypertrophy (LVH) in the absence of increased external load. Recently, nonsurgical septal reduction therapy (NSRT) with intracoron ary ethanol has been introduced to treat severely symptomatic patients with outflow tract obstruction. Its long-term effects on LV mass, however, are unknown. Methods and Results-The LV size, function, and outflow tract gradient of 26 HOCM patients (53 +/- 15 years old) who underwent NSRT were assessed by ec hocardiography at baseline and 1 and 2 years after the procedure. LVH was e valuated by wall thickness of individual myocardial segments, planimetered myocardial area, and mass. The outflow gradient decreased from 36 +/- 6 mm Hg before NSRT to 0 +/- 3 mm Hg at 2 years (P<0.001), with patients experie ncing symptomatic improvement (P<0.05), LV end-diastolic and end-systolic d imensions increased significantly at both 1 and 2 years (P<0.001). All para meters of LVH showed evidence of regression. LV mass decreased (301 <plus/m inus> 78 g at baseline, 223 +/- 5 g at 1 year, and 190 +/- 58 g at 2 years; P<0.01), with the 2-year reduction in mass related to infarct size and the acute reduction in outflow tract gradient (r=0.48, P<0.05 and r=0,63, P<0, 01, respectively). Conclusions-NSRT results in LV remodeling that is characterized by an incre ase in LV size and a decrease in the extent of LVH.