Resection of the septum im hypertrophic obstructive cardiomyopathy. Long-term results in 33 patients

Interventricular septal resection (after Morrow) was performed in 33 patients (24 males, 9 females; average age 48 [13-72] years) with hypertrophic obstructive cardiomyopathy (HOCM). Indications for operation were high resting pressure gradient, severe symptoms despite chronic and high-dosage drug treatment. One patient died on the ninth postoperative day, all others survived. Repeat cardiac catheterization was performed on 20 patients, 1-16 months postoperatively. There was a significant decrease in resting pressure gradient (mean 67 +/- 29 to 7 +/- 10 mm Hg, P less than 0.05). After an average of 30 (range 1-76) months, 25 patients were re-examined: 18 had definite improvement in their symptoms, five partial improvement and only two reported no change. At an operation risk of 3% the procedure is the treatment of choice in patients with symptoms.