Enhanced basal nitric oxide production in heart failure: another failed counter-regulatory vasodilator mechanism?

Abstract Endothelial dysfunction in heart failure could impair nitric oxide production and lead to increased vascular resistance. If endogenous production of nitric oxide is reduced, N G - monomethyl-L-arginine (L-NMMA), an inhibitor of such production, should have a diminished vasoconstrictor effect. We administered L-NMMA to 12 patients being investigated for heart failure. L-NMMA increased median pulmonary and systemic vascular resistances by 61 (range - 3 to 240) and 430 (63 to 1609)dynes s cm -5 , respectively (p