Symptomatic status and prognosis of patients after operation for hypertrophic obstructive cardiomyopathy: efficacy of ventricular septal myotomy and myectomy.

Since 1960, at the National Institutes of Health, ventricular septal myotomy and myectomy has been the mode of treatment for severely symptomatic patients with hypertrophic cardiomyopathy and obstruction to left ventricular outflow who do not respond to medical therapy. Our long-term results of operation for hypertrophic cardiomyopathy are reviewed in 240 patients operated upon prior to 1980. Postoperatively, most patients had improved symptomatically (i.e. 70%) and manifested marked reduction or abolition of the basal left ventricular outflow gradient (i.e. 98%). However, 8% of the patients died of causes related to operation, 9% had persistent or recurrent severe functional limitation, and 7% died up to 19 years postoperatively due to the underlying cardiomyopathy. Of 17 late postoperative deaths, eight were sudden and nine were due to chronic heart failure. In particular, postoperative atrial fibrillation was a significant contributing factor to poor clinical outcome. Hence, while ventricular septal myotomy-myectomy is not always a curative procedure for obstructive hypertrophic cardiomyopathy, the vast majority of patients who survive operation experience long-lasting clinical improvement.