[Atrial natriuretic peptide in cardiac insufficiency].

The role of atrial natriuretic peptide in the pathophysiology of heart failure is unknown. The aim of the study were changes of atrial natriuretic peptide, hemodynamic, renal and hormonal parameters during the development of cardiac failure in an animal model of congestive heart failure in the conscious dog due to rapid right ventricular pacing and in rats with chronic left ventricular failure due to a left ventricular infarction. The effects of intravenous administration of atrial natriuretic peptide were studied in patients with severe congestive heart failure, dogs with experimental cardiomyopathy and conscious rats with acute right ventricular failure due to repeated pulmonary emboli. The results suggest an important role of atrial natriuretic peptide in the early phase of heart failure as a counterregulating system concerning vasoconstrictory and volume retaining mechanisms like the renin-angiotensin-aldosterone system, the sympathetic nerve activity and vasopressin. In chronic heart failure the renal effects of atrial natriuretic peptide are attenuated. Pharmacological doses have beneficial effects on ventricular function by reducing pre- and afterload. The reduction in effectiveness of atrial natriuretic peptide in congestive heart failure may be due to a down-regulation of specific receptors, or caused by hemodynamic renal changes preventing the action of the hormone on the kidney in heart failure or may be due to an activation of counterregulating systems overridding the effects of atrial natriuretic peptide.