Captopril in congestive heart failure: improved left ventricular function with decreased metabolic cost.

The oral angiotensin-converting enzyme inhibitor captopril (CPT) produces beneficial hemodynamic and clinical responses in patients with chronic congestive heart failure (CHF). Cardiac output and stroke volume increase, along with a decrease in pulmonary capillary wedge pressure, indicating improved left ventricular function. During maintenance CPT therapy, the beneficial hemodynamic and clinical effects appear to be sustained. Improved left ventricular pump function with CPT is associated with decreased metabolic cost, as myocardial oxygen consumption consistently decreases in proportion to the decrease in myocardial oxygen demand. Myocardial ischemia occurs infrequently, as is evident from the abnormal myocardial lactate metabolism. Hypotension appears to be the major adverse effect, particularly after the first dose. However, with dose titration and the use of a smaller initial dose, a marked precipitous fall in blood pressure can be avoided in the majority of patients. Thus, CPT may prove to be a useful agent in the vasodilator therapy of chronic CHF.