Abstract 2949: Human Atrial Natriuretic Peptide Improves Myocardial Efficiency in Patients with Heart Failure Due to Idiopathic Dilated Cardiomyopathy
Background: Human atrial natriuretic peptide (hANP) has a great benefit with its vasodilating and natriuretic capacities for the treatment of heart failure (HF). Previous in-vitro studies have shown that cyclic GMP, the second messenger of hANP could alter myocardial inotropy and lusitropy and reduce myocardial oxygen consumption. However, its effects on human failing myocardium have not been fully elucidated. In this study, we examined the effects of hANP on left ventricular (LV) performance and myocardial efficiency in patients with HF due to idiopathic dilated cardiomyopathy (IDC).
Methods: Eight patients with IDC (LV ejection fraction; 31 ± 1%) were instrumented with transducer-tipped conductance and coronary sinus thermodilution catheters. LV contractility (Ees; the slope of end-systolic pressure-volume relation), time constant of LV pressure decay (Tau) and mechanical efficiency (the ratio of LV stroke work to myocardial oxygen consumption (SW/MVO2)) were measured in response to the therapeutic doses of hANP (0.05 μg/kg/min).
Results: The intra-venous infusion of hANP decreased peak LV pressure and LV end-diastolic pressure by 7 ± 2% and 26 ± 2%. HANP shortened Tau significantly. Although hANP did not alter Ees and SW, it reduced myocardial oxygen consumption and improved LV mechanical efficiency. (Table⇓ *: p < 0.05 vs Control)
Conclusion: Therapeutic doses of hANP improve LV lusitropy. HANP also has oxygen saving effects without changing LV inotropy in patients with IDC.