PLASMA-LEVELS OF ATRIAL-NATRIURETIC-PEPTIDE AND OF OTHER VASOCONSTRICTING HORMONES IN PATIENTS WITH CHRONIC HEART-FAILURE - RELATIONSHIP TOEXERCISE CAPACITY

We investigated the relationship between exercise capacity and the lev el of neurohormonal activation at rest and during exercise in patients with various degrees of severity of chronic heart failure. We perform ed exercise testing with measurements of peak oxygen consumption (pVo( 2)) and blood sampling at rest and at peak exercise in eight patients with moderate heart failure (pVo(2)=17+/-0.4 ml/kg/min) (mean+/-S.E.M. ) and eight patients with severe CHF (pVo(2)=9+/-1 ml/kg/min). None of the patients was taking angiotensin converting enzyme inhibitors or b eta-blockers. Plasma levels of atrial natriuretic peptide, cGMP, argin ine-vasopressin, renin, angiotensin II, epinephrine and norepinephrine increased significantly (P<0.01), from rest to peak exercise, in all patients. Among all the studied neurohormonal factors, only atrial nat riuretic peptide levels at rest as well as at peak exercise, in patien ts with severe heart failure were correlated significantly to pVo(2) ( r=-0.77, P=0.04; r=-0.85, P=0.01, respectively) and to exercise durati on (r=-0.72, P=0.05; r=-0.79; P=0.03, respectively). The relationship between plasma levels of atrial natriuretic peptide and of cGMP was sh ifted downward in the more severe patients suggesting the loss of biol ogical activity of atrial natriuretic peptide.