Neurohormonal Responses in Congestive Heart Failure: Effect of Ace Inhibitors in Randomized Controlled Clinical Trials

Abstract

The syndrome of congestive heart failure is characterized by hemodynamic abnormalities [1], impaired exercise capacity [2], neurohormonal activation [3,4], and, most importantly, a relentless progression with high mortality [5]. The mechanisms responsible for the progressive nature of this disease and the subsequent high mortality remain poorly understood. One feature that may be important is the relatively long interval that exists between the initial myocardial damage and the development of congestive heart failure. Although myocardial infarction due to coronary artery disease is the most common cause of heart failure [6], symptoms often take years to appear. In the Framingham studies [7], 15–25% of all the subjects with myocardial infarction developed symptoms of congestive heart failure over a period of 5 years. Similarly, in the Multicenter Diltiazem Postinfarction Trial (MDPIT), which examined the effect of diltiazem in patients following a non - Q myocardial infarct, 24% of asymptomatic subjects in the placebo group, with an ejection fraction <40%, developed congestive heart failure in 2.5 years [8]. It is also clear that this progression may occur without evidence of further episodes of myocardial infarction [9].