Effects of Angiotensin II and Aldosterone on Diastolic Function In Vivo in Normal Man

Abstract

1. Doppler echocardiographic indices of diastolic function and systemic haemodynamics were studied in response to infusions of angiotensin II (1, 2, 5 and 10 ng min−1 kg−1), D-aldosterone (2, 4, 10 and 20 ng min−1 kg−1) and placebo [0.9% (w/v) NaCl] in ten normal male subjects. 2. Dose-related increases in systolic and diastolic blood pressure were observed with angiotensin II infusion at rates of 2 ng min−1 kg−1 and above, whereas no changes in blood pressure occurred with D-aldosterone. No changes in aortic stroke distance or heart rate were seen with either angiotensin II or aldosterone infusion. 3. Compared with placebo, angiotensin II infusion produced a dose-related prolongation of the isovolumic relaxation time [mean and 95% confidence intervals 12.0 (8.2–15.8) ms, P < 0.001] at 10 ng min−1 kg−1, and a significant reduction in the ratio between early and late transmitral flow velocity integrals at 2 ng min−1 kg−1, [−0.84 (−1.63 to −0.05), P < 0.05] and 5 ng min−1 kg−1 [−0.76 (−1.47 to −0.05), P < 0.05]. No changes in Doppler echocardiographic indices of diastolic function were observed with D-aldosterone infusion. 4. These data suggest that angiotension II, even at a sub-pressor concentration, produces an impairment of left ventricular diastolic filling, which occurs independently of its effect on aldosterone release.