COMPARATIVE EFFECTS OF ANGIOTENSIN-II ON DOPPLER PARAMETERS OF LEFT AND RIGHT HEART SYSTOLIC AND DIASTOLIC BLOOD-FLOW

1 The purpose of the study was to investigate the effects of angiotens in II on Doppler parameters of right ventricular systolic and diastoli c blood how, and to compare these with effects on the left heart, in n ormal subjects. 2 Pulsed-wave Doppler measurements were made in eight normal volunteers: after a 30 min control i.v. infusion of dextrose, a fter 30 min stepwise infusions of angiotensin II (2, 4 and 6 ng kg(-1) min(-1)), and finally 30 min after stopping the 6 ng kg(-1) min(-1) d ose of angiotensin II. Aortic (Ao) and pulmonary (Po) systolic ejectio n parameters, as well as mitral (Mi) and tricuspid (Tc) diastolic fill ing parameters were measured. 3 Ao and Po maximal velocity were both s ignificantly reduced by angiotensin II, whereas there were significant opposite effects on Ao (reduced) and Po (increased) mean acceleration . There was a dose-related fall in Po acceleration time with angiotens in II, whilst Ao acceleration time remained unchanged. 4 Mi and Tc ear ly diastolic filling velocities were not significantly altered by angi otensin II compared with baseline, although there was a significant re bound increase in both Mi and Tc early filling after cessation of angi otensin II infusion. Mi and Tc pressure half-times were not significan tly changed. 5 In conclusion, angiotensin II produced changes in Po ej ection parameters consistent with a presser response in the pulmonary vascular bed. Neither right nor left ventricular diastolic filling wer e directly affected by angiotensin II. The differential effects of ang iotensin II on Po and Ao ejection parameters might be due to inherent differences in basal pulmonary and systemic vascular tone.