Propranolol in management of muscular subaortic stenosis.

Abstract

The results of long-term treatment with a beta-adrenergic blocking drug (propranolol) in 5 patients with proven muscular subaortic stenosis are reported. Four patients showed initial improvement. Treatment had to be discontinued in the 5th-patient because of increased fluid retention and shortness of breath. There was no change in the ventilatory capacity after treatment, nor was there significant change in the ventilatory response to exercise. The physical working capacity (pulse rate/work ratio) showed an improvement in all 5 patients, due to the marked reduction of heart rate at rest and on exercise. The patients most likely to benefit from this form of treatment are those with symptoms associated with a high resting and exercise heart rate. Patients demonstrating fluid retention should not be treated with beta-adrenergic blockade. Beta-adrenergic blockade may be of value in the long-term management of certain patients with muscular subaortic stenosis. Surgical treatment will be required in those patients who do not maintain initial improvement, or in those where blockade is contraindicated.