[Cardiovascular hemodynamics in patients with essential hypertension during multi-stage exercise]

We investigated cardiovascular hemodynamics in patients with essential hypertension at rest and during exercise. Eight patients with borderline hypertension (Group B), 18 patients with sustained hypertension, and 10 normotensive subjects (Group N) were studied. Patients with sustained hypertension were categorized in two groups; 10 patients without cardiac hypertrophy (Group NH), and eight patients with cardiac hypertrophy (Group HH). To assess the cardiovascular hemodynamics, M-mode echocardiograms, electrocardiograms and carotid pulses were recorded during multistage exercise using a supine bicycle ergometer. Blood pressure was measured simultaneously by the cuff method. At rest, isovolumic relaxation times (IRT) in Groups NH and HH were significantly prolonged as compared with that of Group N. The IRT of Group HH was significantly prolonged as compared with that of Group NH (Group N: 0.06 +/- 0.01 sec, Group B: 0.07 +/- 0.01 sec, Group NH: 0.08 +/- 0.02 sec, Group HH: 0.09 +/- 0.01 sec, respectively). Only the atrial filling fraction of Group HH was significantly increased over that of Group N (Group N: 25.6 +/- 12.1%, Group B; 30.0 +/- 8.1%, Group NH: 27.9 +/- 11.3%, and Group HH: 41.4 +/- 13.1%, respectively). The total peripheral vascular resistance (TPR) in Groups NH and HH was significantly increased over that of Group N (Group N: 1600 +/- 224 dyne/sec/cm-5, Group B: 1704 +/- 465 dyne/sec/cm-5, Group NH: 2370 +/- 608 dyne/sec/cm-5, and Group HH: 3290 +/- 1598 dyne/sec/cm-5, respectively). There was no significant difference in the cardiac index, ejection fraction or heart rate among all groups at rest and during exercise. However, the difference between TPR at rest and TPR at a load of 75 watt (delta TPR) was increased in Groups NH and Group HH over Group N (Group N: 558 +/- 166 dyne/sec/cm-5, Group B: 614 +/- 336 dyne/sec/cm-5, Group NH: 883 +/- 415 dyne/sec/cm-5, and Group HH: 1306 +/- 774 dyne/sec/cm-5, respectively). From these findings, we concluded that there is early diastolic left ventricular dysfunction in Groups NH and HH, and that the degree is more distinct in Group HH. It seems that systolic left ventricular function of both groups is normal during moderate exercise loads, and marked reduction of the TPR in both groups during exercise may be caused by marked peripheral vascular dilatation.