Potential for altering the natural history of congestive heart failure: need for large clinical trials.

Congestive heart failure (CHF) is a major clinical and public health problem; moreover, its incidence is increasing. Once this syndrome is manifest, the mortality rate is very high. To date, none of the drugs available for its treatment has been shown to reduce mortality. It is theoretically possible that in patients with overt CHF, drug treatment may not alter prognosis. This hypothesis suggests that patients at high risk of heart failure should be treated before CHF becomes manifest. Alternatively, the trials of patients with manifest CHF may have been unpromising, simply because they were too small. These considerations indicate an urgent need for very large studies of both categories of patients--a "prevention" trial in those without overt CHF and a "treatment" trial in those with overt CHF.