Increased Nitric Oxide Production in Heart Failure and Correlation with Functional Severity
The role of nitric oxide (NO) in heart failure is unknown. Studies of isolated blood vessels from patients with heart failure demonstrate impaired NO-dependent relaxation to acetylcholine. On the other hand, endomyocardial biopsy specimens from patients with dilated cardiomyopathy show increased activity of the inducible isoform of nitric oxide synthase (iNOS). Plasma levels of TNF-α, an activator of iNOS, are increased in heart failure, and TNF-α has been shown to have negative inotropic effects in hamster papillary muscle through an NO-dependent mechanism.