Objectives - To study the outcome of septal myectomy in patients with hypertrophic obstructive cardiomyopathy. Design - Septal myectomy in patients with hypertrophic cardiomyopathy with obstruction of the left ventricular outflow tract (HOCM) is symptomatically effective, and complication rates have been found to be low in large centres performing the procedure routinely. Representing a small centre we studied the outcome after septal myectomy in 11 consecutive patients, aged 44± 21 (mean ± SD) years with HOCM myectomized at our institution from 1991 to 1998. The patients were evaluated preoperatively using echocardiography and left-sided heart catheterization. Results - Eight patients were operated on after medical treatment had failed and three after sudden deterioration of cardiac function. A Morrow myectomy was performed in 10 patients and a modified Konno procedure in one. Significant reductions were observed in left ventricular outflow tract gradients (77±29 to 10±7 mmHg, p<0.01; n = 11), the degree of mitral valve regurgitation (grades 0-3) (1.7±1.0 to 0.8±0.7, p<0.01; n = 11), NYHA functional classification score (2.4 ± 1.0 to 1.5±0.7, p <0.01; n = 11) and all five patients with angina preoperatively had an improved CCS angina classification score. There were no operative or early postoperative (30 days) deaths. One patient operated on with the modified Konno procedure was reoperated for a septal patch suture leak. During follow-up (43±24 months, range 11-83), the linearized mortality rate was 3.6% per year. One patient died from a pancreas cancer, one probably from coronary artery disease and one suddenly of unknown cause. Conclusion - We conclude that septal myectomy efficiently relieves symptoms in HOCM patients, possibly reflecting the direct as well as secondary effects of left ventricular outflow tract gradient reduction. The present results, obtained at a smaller centre for this procedure, should be considered when choosing from available therapeutic alternatives when medical therapy fails: dual chamber pacemaker implantation, percutaneous transluminal septal myocardial ablation or myectomy.