Peptides, endothelium and left atrial function

Evidence suggests that atrial natriuretic peptide and brain natriuretic pep tide are related to left atrial function. Clinical studies indicate that el evated levels of natriuretic peptides are associated with long-term prognos is in patients with congestive heart failure and in survivors of an acute m yocardial infarction. The distension of the left atrium, rather than the di lation of the left ventricle, is related to the concentration of atrial nat riuretic peptide. Furthermore, the endothelial-derived nitric oxide may pla y an important role in the heart by influencing myocardial inotropic and ch ronotropic responses and subsequently the left atrial function. Studies hav e shown that nitric oxide attenuates cardiac myocyte contraction and mediat es vagal inhibition of cardiac inotropic response to beta-adrenergic stimul ation. Prostacyclin release from endocardial endothelial cells of the left atrial appendage was much less than with that from the right ventricle or p ulmonary arteries.