Radioimmunoassay of Plasma Arginine Vasopressin in Hyponatremic Patients with Congestive Heart Failure

HYPONATREMIA occurs frequently in patients with congestive heart failure who have moderate fluid intakes (1 to 3 liters per day).1 It is not clear whether persistent release of arginine vasopressin (AVP — the mammalian antidiuretic hormone ADH) or intrarenal factors account for this impaired water excretion. When bioassay techniques have been used to assess the role of AVP in the hyponatremia associated with congestive heart failure, the results have been conflicting.2 3 4 5 In this investigation, we used a sensitive radioimmunoassay technique to measure AVP in 37 patients with congestive heart failure and associated hyponatremia. AVP levels were detectable in 30 of . . .