Plasma Arginine Vasopressin in Hyponatremic Patients with Heart Failure

To the Editor: We offer the following comments in reference to the paper by Szatalowicz et al. 1 in the July 30 issue, reporting detectable arginine vasopressin (AVP) levels in some hyponatremic patients with heart failure. Although 3.04±0.84 pg per milliliter was the mean value for AVP in the group with "detectable" levels, this number is somewhat misleading because of the presence of several very high values. Two thirds of the levels were actually below 2.0 pg per milliliter, and half of those were under 1.0 pg per milliliter. Thus, in most subjects, even in this group, AVP was nearly completely . . .