Natural history of idiopathic dilated cardiomyopathy. Implications for future therapy.

Idiopathic dilated cardiomyopathy can present in a number of different ways, with the majority of patients having heart failure. Natural history studies show a poor prognosis for most patients with this disease. However, a substantial number may stabilize or even improve, and have a survival curve similar to patients without the disease. Patients can be stratified for relative risk of mortality by age, cardiomegaly on chest roentgenograph, ventricular function, and quantitative assessment of ventricular arrhythmias. Therapy can be divided into three categories: alteration of factors associated or contributors to ventricular dysfunction, supportive therapy, and investigational therapy. The efficacy of therapy should be judged by its effect on functional capacity and survivorship. The first category includes controlling hypertension and abstaining from alcohol. This often leads to improved functional status, and may improve survival. The second category includes anticoagulant therapy and, most importantly, medications for heart failure (digoxin, diuretics, vasodilators, nonglycoside inotropes, etc.). These agents may improve functional status, but in general have had little impact on survival. Investigational medical therapy for future use depends upon identification of factors involved in the genesis of the disease and the pathophysiologic mechanisms responsible for morbidity and mortality. The inflammatory component in the genesis and/or maintenance of cardiomyopathy, the importance of frequent ventricular arrhythmias in prognosis and the influence of endogenous vasoconstrictors on heart failure and arrhythmias, have been mentioned as such areas of interest.(ABSTRACT TRUNCATED AT 250 WORDS)