W.H. Merrill*, G.C. Freisinger, T.P. Graham, Jr., D.C. Drinkwater, K.R. Christian*, H.W. Bender, Jr.*

Vanderbilt University, Dept. of Cardiac and Thoracic Surgery

Nashville, Tennessee, USA

Controversy continues over the most effective treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM). Treatment options include medical therapy, pacemaker insertion, mitral valve replacement, and surgical resection of obstructing muscle. The long-term results of the various treatment options are not well defined. We conducted a study to demonstrate that septal myectomy is efficacious in reducing or abolishing left ventricular outflow tract gradient and that it leads to long-lasting symptomatic improvement in most patients.

Twenty-two consecutive patients underwent septal myectomy between 1981 and the present. Their records were reviewed to document the details of their preoperative status, hospital course, their subsequent clinical outcome, and current status.

Mean age at operation was 31.3 years. Preoperatively, most patients were disabled by typical symptoms despite aggressive medical management. Mean resting gradient was 78 mm Hg. Nine patients required simultaneous associated cardiac procedures. There were no perioperative deaths and minimal morbidity. Two patients died late at 6 and 9 years postoperatively, respectively, due to congestive heart failure and arrhythmias. Long-term survivors have been followed up a mean of 6.6 years. Currently all have minimal or no symptoms. The mean rest gradient is 12 mm Hg.

Septal myectomy reduces or abolishes left ventricular outflow tract gradient in HOCM. Myectomy provides long- lasting symptomatic improvement in most patients. The clinical status of patients late postoperatively may be impacted by the development of arrhythmias and myocardial dysfunction.