Long-term control of congestive heart failure with captopril.

The long-term effects of captopril therapy were assessed by sequential hemodynamic studies over a 6 month period in 19 patients with resistant congestive heart failure. Initial improvement during the first week of therapy was noted only in 11 and was marked by significant (p less than 0.005) increases in cardiac output and stroke volume, slowing of heart rate, and reduction of total peripheral resistance. Of the remaining eight patients, seven improved subsequently with maintained therapy so that by the end of 3 months of treatment only one patient failed to respond significantly. The hemodynamic index that reflected response most consistently was the shortening in pulmonary mean transit time. Simultaneously with clinical improvement there was a reduction in cardiopulmonary volume that reflected a reduction in pulmonary congestion and probably systemic vasodilation. Associated with these hemodynamic changes there was an increase in plasma renin activity and a significant reduction in plasma aldosterone, but these changes did not differ significantly between patients who responded markedly and those who responded moderately to converting enzyme inhibition. These results suggest that the response of congestive heart failure to captopril can occur gradually. Improvement was related to peripheral hemodynamic changes which led to a reduction in both total peripheral resistance and cardiopulmonary volume. The reduction in the plasma aldosterone/renin activity ratio was an effective marker of compliance.