Angiotensin converting enzyme inhibition restores cardiac and hormonal responses to volume overload in patients with dilated cardiomyopathy and mild heart failure

Background. Angiotensin converting enzyme (ACE) inhibition exerts a favorable effect on the response to exercise in heart failure. This study was planned to define the influence of ACE inhibition on the adaptation to volume overload. Methods and Results. We studied the hemodynamic, hormonal, and renal responses to acute volume expansion (sodium chloride, 0.9%, 0.25 ml·kg^-1·min^-1 for 2 hours) in patients with idiopathic or ischemic dilated cardiomyopathy and mild heart failure (New York Heart Association class I or II, ejection fraction ≤50%). The patients were studied without any pretreatment (n=14) or after 1 week of treatment with the oral ACE inhibitor quinapril at a dosage of 10 mg/day (n=11). Seven patients were studied during constant intravenous infusion with nitroglycerin (0.1 μg·kg^-1·min^-1). The study groups had similar hemodynamic and clinical characteristics and hormonal profile at baseline evaluation. In the untreated patients, volume expansion did not increase left ventricular end-diastolic volume measured by echocardiography and was associated with a reduction in ejection fraction (p0.05) estimated by plethysmography. In addition, plasma atrial natriuretic factor did not change, and plasma norepinephrine was increased by saline loading. In contrast, in the patients treated with quinapril, volume expansion induced an increase of both left ventricular volumes (p