RESUMEN
Plasma renin activity, plasma volume as well as estimation of stroke, volume cardiac output, peak aortic flow velocity, acceleration time and systemic peripheral resistance were done using Doppler echocardiography in 36 individuals divided into three groups. The study revealed a statistically significant decrease in plasma renin activity in old hypertensive group 1 as compared to the old normal group 2 and young group 3. Plasma volume showed a slight significant decrease in group 1 as compared to group 2 while the echocardiographic study showed a significant decrease in stroke volume, cardiac output and cardiac index in old hypertensive subjects as compared to the other two groups which may be explained by low heart rate, or reduced vigor of left ventricular contractility in old hypertensive subjects. On the other hand, the peak aortic flow velocity and acceleration time did not show significant variation in the three studied groups. The study revealed a significant increase in systemic peripheral resistance in group 1 when compared to the other two groups which is multifactorial