Percutaneous transluminal septal myocardial ablation (PTSMA) is a new therapeutic option for patients with hypertrophic obstructive cardiomyopathy (HOCM). In the present study, the acute and follow-up results of PTSMA were evaluated. From August 1997 to March 2003 27 medically refractory patients (New York Heart Association (NYHA) functional class 2.9+/-0.6) with HOCM underwent PTSMA. The target septal branch was determined by probationary ballooning in 3 and by myocardial contrast echocardiography in 24 patients. The mean resting left ventricular outflow tract pressure gradient (PG) was reduced from 70+/-44 to 24+/-22 mmHg (p<0.0001); the peak concentration of creatine kinase was 1545+/-686 IU/L. Although transient trifascicular block was observed in 14 patients, permanent pacemaker implantation was not required. There were no major adverse cardiac events during the hospital stay; the mean clinical follow-up was 2.2+/-1.7 years. Repeated PTSMA was needed in 1 patient; however, symptomatic improvement had been well preserved in all patients (NYHA class 1.2+/-0.4). Follow-up echocardiographic examination showed sustained improvement in PG, septal and left ventricular posterior wall thicknesses, and the grade of systolic anterior movement and regurgitation of the mitral valve. In conclusion, PTSMA is a safe and effective therapeutic option for medically refractory patients with HOCM.