Clinical decisions in the management of the cardiomyopathies.
The cardiomyopathies are defined and classified into hypertrophic, dilated and restrictive types. In hypertrophic cardiomyopathy the major abnormalities of structure (massive ventricular hypertrophy, myofibrillar disarray, and narrow intramural coronary arteries) and of function (excessive ventricular contraction, systolic pressure gradients, increased ventricular stiffness with impaired relaxation and a tendency for sudden death) are used as the basis for selective and rational treatment with beta-blocking, calcium blocking, or antiarrhythmic agents, or a combination. Treatment is aimed at relieving symptoms, improving prognosis and slowing the progress of disease. Additional methods of treatment involving pacemakers and defibrillators are covered, and the place of septal resection, mitral valve replacement and cardiac transplantation discussed. General management and advice to the patient, and the treatment of complications such as atrial fibrillation, congestive heart failure and infective endocarditis, are also covered. In dilated cardiomyopathy measures to improve ventricular function by vasodilator therapy and the place of antiarrhythmic and anticoagulant drugs are discussed. The controversial treatment with beta-adrenergic blocking agents is reviewed, and the place of immunosuppressive therapy assessed. The possible use of antiviral agents in the future is commented upon, and cardiac transplantation is emphasised as the most effective, although radical, means of improving prognosis in intractable cases. In restrictive cardiomyopathy due to endomyocardial fibrosis, treatment of the initial inflammatory stage with steroids or sulphonylurea, and of the later fibrotic and thrombotic stage with anticoagulants and endocardectomy, is surveyed. The possible place of cardiac transplantation both for endomyocardial fibrosis and amyloid heart disease is mentioned, caution being urged when either of these conditions involves organs other than the heart.