[Hyponatraemia, antagonists of the antidiuretic hormone and cardiac failure]

Hyponatraemia is a common clinical finding in cardiac failure, complicating the management of these patients. Vasopressin plays a fundamental role in the physiopathology of the hyponatraemia of cardiac failure and binds to two distinct specific receptors, receptor V1a and V2. The V2 receptors, situated in the renal collecting duct, control the resorbtion of free water. The V1a receptors, present everywhere, are responsible for the vasoconstrictive effect of vasopressin. Specific antagonists of vasopressin receptors are being evaluated in pathologies associated with hyponatraemia. The preliminary results in patients with cardiac failure are encouraging and mortality studies are underway.