Background-Left ventricular outflow tract (LVOT) obstruction is frequently responsible for symptoms in hypertrophic obstructive cardiomyopathy (HOCM). Medical therapy is often not sufficient to control these symptoms, and surgical myotomy-myomectomy is required. Methods and Results-We enrolled 33 symptomatic patients with HOCM and obstruction (Ն40 mm Hg gradient at rest or Ն60 mm Hg dobutamine-provoked). By contrast echocardiography, the bulging septum was localized and infarcted by injection of 2 to 5 mL of absolute ethanol into the septal artery(ies) supplying the hypertrophied area. Baseline echocardiograms with Doppler, myocardial perfusion tomograms, and treadmill exercise or pharmacological testing were compared with those at 6 weeks and 6 months. The mean rise in creatine kinase was 1964Ϯ796 U. All patients experienced symptomatic relief; NYHA class decreased from 3.0Ϯ0.5 to 0.9Ϯ0.6 (PϽ0.001). Exercise time increased from 286Ϯ193 to 421Ϯ181 seconds (Pϭ0.03). The resting and dobutamine-provoked gradient decreased from 49Ϯ33 and 96Ϯ34 mm Hg to 9Ϯ19 (PϽ0.001) and 24Ϯ31 mm Hg (PϽ0.001), respectively. Echocardiograms repeated at 6 weeks after the procedure showed a 28% reduction in septal thickness and 17% reduction in left ventricular mass. Myocardial perfusion imaging showed a "septal amputation pattern," with scarring in the upper and middle septal areas.Complete heart block developed in 11 patients, who then required permanent pacemaker implantation. Conclusions-Echocardiography-guided ethanol septal reduction in patients with HOCM is a safe, minimally invasive procedure that provides symptomatic relief with improved hemodynamic and left ventricular parameters. (Circulation. 1998;98:1750-1755.)

Nonsurgical septal reduction therapy resulted in a significantly higher incidence of complete heart block, but the risk was reduced with contrast echocardiography and slow ethanol injection. Surgical myectomy resulted in a significantly higher incidence of mild aortic regurgitation. Nonsurgical septal reduction therapy, guided by contrast echocardiography, is an effective procedure for treating patients with HOCM. The hemodynamic and functional improvements at one year are similar to those of surgical myectomy.

Nonsurgical septal reduction therapy is an effective therapy for symptomatic patients with hypertrophic obstructive cardiomyopathy with persistence of the favorable outcome up to one year after the procedure.

Background-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 intracoronary 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 (53Ϯ15 years old) who underwent NSRT were assessed by echocardiography at baseline and 1 and 2 years after the procedure. LVH was evaluated by wall thickness of individual myocardial segments, planimetered myocardial area, and mass. The outflow gradient decreased from 36Ϯ6 mm Hg before NSRT to 0Ϯ3 mm Hg at 2 years (PϽ0.001), with patients experiencing symptomatic improvement (PϽ0.05). LV end-diastolic and end-systolic dimensions increased significantly at both 1 and 2 years (PϽ0.001). All parameters of LVH showed evidence of regression. LV mass decreased (301Ϯ78 g at baseline, 223Ϯ5 g at 1 year, and 190Ϯ58 g at 2 years; PϽ0.01), with the 2-year reduction in mass related to infarct size and the acute reduction in outflow tract gradient (rϭ0.48, PϽ0.05 and rϭ0.63, PϽ0.01, respectively). Conclusions-NSRT results in LV remodeling that is characterized by an increase in LV size and a decrease in the extent of LVH.

Estimation of the size of the septal vascular territory with MCE is accurate, safe and feasible in essentially all patients during NSRT. MCE can delineate the perfusion bed of the septal perforators and can predict the infarct size that follows ethanol injection.