INCREASED NITRIC-OXIDE PRODUCTION IN HEART-FAILURE

The role of nitric oxide in heart failure is unknown. The high-capacit y inducible isoform of nitric oxide synthase is present in the myocard ium of patients with idiopathic dilated cardiomyopathy. Plasma nitrate , the stable end-product of nitric oxide production, was significantly increased in patients with heart failure compared with normal control s (means 51.3 and 24.6 mu mol/L). Vasodilation caused by increased nit ric oxide may compensate for the vasoconstrictor effect of neurohumora l adaptions to heart failure. Alternatively, excess production may be detrimental to the heart by a direct negative inotropic effect.