ACUTE EFFECTS OF ATRIAL-NATRIURETIC-PEPTIDE ON LEFT-VENTRICULAR DIASTOLIC FUNCTION - A PULSED WAVE DOPPLER STUDY IN MAN

Doppler echocardiographic indices of diastolic function and systemic h aemodynamics were studied in response to infusions of atrial natriuret ic peptide (0.5, 1, 2, 5 pmol . kg(-1). min(-1)) and placebo (0.9% (w/ v) saline) in ten normal male subjects. Compared with placebo, atrial natriuretic peptide infusion produced a significant and close-related reduction in the isovolumic relaxation time [(mean and 95% CI) -5.9 (- 9.2 to -2.6) ms (P<0.01) at 5 pg . kg(-1) min(-1)] and a significant i ncrease in the ratio between early and late transmitral peak velocitie s [0.46 (0.02 to 0.89) (P<0.051 at 5 pg . kg(-1). min(-1)]. No signifi cant changes in heart rate, blood pressure or aortic stroke distance w ere observed with infusion of atrial natriuretic peptide compared with placebo. These data suggest that pathophysiological plasma concentrat ions of atrial natriuretic peptide improve diastolic function by incre asing the rate of myocardial relaxation.