Article: PDF OnlyCody R. J.Journal of Cardiovascular Pharmacology: 1986 - p S58-S65 Free Abstract Summary The renin-angiotensin system is activated in the majority of patients with chronic congestive heart failure. This may be part of the pathophysiology of the disease, a secondary phenomenon, or the result of intense diuretic therapy. Irrespective of the mechanism of renin-angiotensin activation, converting enzyme inhibitors are an effective form of therapy as well as a means to evaluate pathophysiologic mechanisms of congestive heart failure. Because of the activation of the renin-angiotensin system, angiotensin-mediated vasoconstriction and aldosterone-mediated sodium retention can be suppressed and, in some individuals, completely blocked by converting enzyme inhibitors. Improved forward cardiac flow and reduction of pulmonary congestion occur with reversal of vasoconstriction, so that relief of edema, due to enhanced sodium and water excretion, will occur. While it is easy to identify a close correlation between markers of renin-angiotensin activity and the initial response to converting enzyme inhibitors, it is more difficult to identify this response long-term. This may be due to changes in dietary sodium intake, intensity of diuretic therapy, or alteration in renal blood flow and function. Clinically, however, the response to converting enzyme inhibitors is favorable in the majority of people. © Lippincott-Raven Publishers.