ATRIAL-NATRIURETIC-PEPTIDE AND DIASTOLIC FUNCTION IN YOUNG ESSENTIAL HYPERTENSIVES

Plasma levels of noradrenaline and atrial natriuretic peptide were mea sured during rest and exercise in 15 young patients (33.2 +/- 7.4 year s) with mild to moderate essential hypertension and in 15 normotensive healthy volunteers (30.4 +/- 5.8 years). While enddiastolic (51 +/- 6 mm vs. 49 +/- 4 mm) and endsystolic dimension (30 +/- 5 mm vs. 30 +/- 3 mm) were comparable in both groups left ventricular muscle mass was significantly higher in patients with hypertension (134 +/- 28 g/m2 v s. 87 +/- 23 g/m2, p less-than-or-equal-to 0.001) together with a prol onged acceleration time (98 +/- 19 ms vs. 68 +/- 10 ms, p less-than-or -equal-to 0.001) and a decreased ratio of early and atrial velocity-ti me-integrals of transmitral flow (2.48 +/- 1.05 vs. 3.59 +/- 1.19, p l ess-than-or-equal-to 0.05). In hypertensive patients noradrenaline pla sma levels were higher during rest (305 +/- 133 pg/ml vs. 182 +/- 90 p g/ml, p less-than-or-equal-to 0.01) and exercise (465 +/- 261 pg/ml vs . 245 +/- 108 pg/ml, p less-than-or-equal-to 0.01). Resting plasma lev els of atrial natriuretic peptide were similar in both groups and did not change with exercise in the normotensive controls (from 43 +/- 22 pg/ml to 56 +/- 24 pg/ml). However, there was a significant increase i n hypertensive patients (from 49 +/- 27 pg/ml to 88 +/- 83 pg/ml, p le ss-than-or-equal-to 0.05) and the relative change in ANP concentration correlated with the ratio of early and atrial velocity-time-integrals of transmitral flow (r = -0.70, p less-than-or-equal-to 0.01). Thus, elevated plasma levels of atrial natriuretic peptide in patients with arterial hypertension probably only reflect the diastolic dysfunction in hypertensive hearts, independent of left ventricular muscle mass an d sympathetic activity.