IMPAIRED LEFT-VENTRICULAR RELAXATION AND ARTERIAL STIFFNESS IN PATIENTS WITH ESSENTIAL-HYPERTENSION

1. This study was designed to determine how left ventricular relaxatio n function in patients with essential hypertension is impaired by arte rial haemodynamic load that is increased in early ejection phase. Thes e patients did not suffer from cardiac hypertrophy or disturbed corona ry perfusion. We used a high-fidelity multisensor catheter to record p ressure and flow signals in the ascending aorta. The timing and magnit ude of wave reflection were obtained by decomposing the measured waves into their forward and backward components. Radionuclide angiography was employed to obtain the time-activity curve. The left ventricular r elaxation function was assessed by analysing the time-activity curve, which was filtered using Fourier expansion with the number of harmonic s for minimum error. 2. In comparison with age-matched normotensive su bjects (seven subjects with mean blood pressure 97 mmHg), hypertensive subjects (seven subjects with mean blood pressure 138 mmHg) had a sho rter backward wave arrival time (193+/-26 versus 258+/-35 ms) and a hi gher reflection factor (0.58+/-0.12 versus 0.42+/-0.07). Isovolumic re laxation period was prolonged in hypertensive subjects (118+/-19 versu s 90+/-19 ms). There was an inverse correlation between isovolumic rel axation period and backward wave arrival time in all 14 subjects (r= - 0.67, P <0.05). In contrast, there were no significant differences in cardiac output and time to peak ejection rate between the two groups. 3. Our analyses revealed that early return of the enhanced wave refle ction may profoundly impair left ventricular relaxation function in pa tients with hypertension. The prolonged isovolumic relaxation and unal tered cardiac output suggested that relaxation abnormalities may have a tendency to precede systolic dysfunction in our hypertensive subject s.