Medical and Surgical Treatment of the Cardiomyopathies

The idiopathic cardiomyopathies can be classified into congestive, restrictive, obliterative, and hypertrophic (nonobstructive and obstructive) types. The treatment of the congestive, restrictive, and obliterative cardiomyopathies is essentially a good antifailure regimen, correction of arrhythmias, and prevention of emboli. In hypertrophic nonobstructive cardiomyopathy, in addition to the above therapeutic principles, beta-adrenergic blocking agents may be of value. Treatment is most effective in hypertrophic obstructive cardiomyopathy (muscular or hypertrophic subaortic stenosis), in which propranolol has been of considerable help to patients with latent obstruction to left ventricular outflow and to those with resting obstruction who are mildly symptomatic. Patients with resting obstruction and severe symptoms usually experience only transient improvement on propranolol and eventually require operative intervention. Surgery for this condition varies from ventriculomyotomy to extensive resection of muscle and mitral valve replacement. A simple ventriculomyotomy abolishes the abnormal systolic anterior movement of the anterior mitral leaflet, relieves the outflow-tract obstruction and the mitral regurgitation, reduces the left ventricular end-diastolic pressure, and produces significant symptomatic improvement in the majority of patients. Extensive muscle resection is not essential to achieve these benefits. Although mitral valve replacement has been employed by some as the surgical procedure of choice, the authors would prefer to reserve this form of surgical therapy for those patients with severe mitral regurgitation that is independent of the outflow-tract obstruction.