Nitric oxide and efficiency of the right heart

Abstract

See article by Setty et al. (pages 431–436) in this issue . Several differences between right and left heart are known: the effect of cardiac contraction on coronary arterial inflow, autoregulation, and oxygen extraction. Setty et al. [1] show in their study the relationships between function and oxygen consumption of the right heart under control and ischemic conditions and the role of nitric oxide (NO). It turns out that these relationships also differ between left and right heart. Coronary flow depends on perfusion pressure and cardiac oxygen consumption [2]. NO decreases vascular smooth muscle tone and thus modulates flow. NO also promotes vascular growth and affects cardiac function in terms of metabolism, contractility, rhythmicity, and growth [3]. Early studies on ischemia and the role of NO mainly emphasized the vasodilatory effect on the coronary vasculature and thus a protective role of NO. At higher concentrations, NO has a cGMP-independent negative inotropic effect [4]. NO synthase inhibition impairs the efficiency of oxidative metabolism and cardiac function, while during moderate ischemia, NO synthase appears not to be involved in cardiac metabolism … *Tel.: +31 20 4448111; fax: +31 20 4448255. Email address: n.westerhof{at}vumc.nl