Hypertrophic obstructive cardiomyopathy. Initial results and long-term follow-up after Morrow septal myectomy.

Abstract

This study was performed to assess the initial results and long-term follow-up of Morrow septal myectomy for patients with hypertrophic obstructive cardiomyopathy (HOCM). We studied 38 consecutive patients with HOCM (age, 13 to 74 years) who underwent a Morrow septal myectomy between 1977 and 1992. There were no perioperative deaths, and the postoperative course was uneventful for all except 2 of the patients. One patient required implantation of a pacemaker due to a complete heart block, and in 1 patient a small ventricular septal defect was caused. Follow-up (mean, 6.8 years) was 100% complete. No patient was reoperated for recurrent HOCM. All except 1 patient experienced a major functional improvement with a decrease of the mean New York Heart Association functional class from 3.0 before operation to 1.5 at follow-up (P < .001). Symptoms persisting during follow-up were angina pectoris in 3 of 22 patients (14%), dyspnea in 6 of 30 patients (20%), dizzy spells in 2 of 12 patients (17%), and syncope in 2 of 10 patients (20%). During follow-up no HOCM related death occurred. All patients were restudied by Doppler echocardiography. The peak gradient in the left ventricular outflow tract decreased from 72 +/- 30 mm Hg (range, 31 to 144 mm Hg) to 6 +/- 4 mm Hg (range, 0 to 20; P < .001). A systolic anterior movement was seen in 8 patients (21%) compared with 32 patients (97%) before the operation (P < .001). The left ventricular outflow tract diameter increased from 17 +/- 3 mm (range, 10 to 23 mm) to 22 +/- 3 mm (range, 15 to 33 mm; P < .001), and the mean subaortic septal thickness decreased from 23 +/- 5 mm (range, 15 to 35 mm) to 15 +/- 6 mm (range, 8 to 30 mm; P < .001). Morrow septal myectomy for patients with HOCM is a safe procedure with an excellent clinical and Doppler echocardiographic long-term follow-up.