[Atrial natriuretic peptide (ANP) in essential hypertension: a humoral marker for salt sensitivity and hypertensive heart disease at a clinically asymptomatic stage?].

Out of 32 patients (f = 10, m = 22; mean age: 46 +/- 3 years) with untreated essential (primary) hypertension (WHO-classification I-III) and without clinical signs of congestive heart failure or chronic renal failure, 19 showed plasma-ANP base levels above the normal range (greater than 100 pg/ml; normal range: 50 +/- 10 pg/ml). While high sodium loading caused an increase of plasma ANP levels and a concomitant decrease of plasma renin and aldosterone concentrations, low sodium loading caused the opposite pattern of ANP and renin/aldosterone secretion. Some patients with essential hypertension with highly elevated plasma ANP levels (10-20-fold above the normal range) showed an only moderate decrease of ANP and a slight increase of renin under a low sodium diet. Plasma ANP levels were significantly correlated with the heart volume (r = 0.54; p less than 0.05; radiologically determined), the electrocardiographic signs of left ventricular hypertrophy (Sokolow-Lyon index; r = 0.62; p less than 0.05) and with the left atrial diameter (r = 0.34; p less than 0.05; determined by 2-D-echocardiography). We speculate that high levels of plasma ANP in patients with essential hypertension might be interpreted as a compensatory mechanism either for an insufficient excretion of sodium or for myocardial dysfunction.