Abstract
The autonomic sympathetic reflexes to sustained handgrip, upright tilt and the Valsalva maneuver, were tested in 26 patients with labile and 26 with fixed essential hypertension. Sustained handgrip increased systolic (SAP), diastolic (DAP) and mean arterial (MAP) pressure, heart rate (HR), cardiac index (CI), tension time index (TTI) (p < .01), and had no effect on total peripheral resistance index (TPRI) and left ventricular ejection rate index (LVERI) in both groups of patients. However, the response to upright tilt and the Valsalva maneuver was different in the two groups. Upright tilt in labile hypertensives increased DAP, MAP, HR, and TPRI (p < .001); decreased CI, stroke index (SI) and LVERI (p < .01) and had no effect on SAP. In fixed hypertensives, it decreased SAP, MAP, CI, SI and LVERI (p < .001); increased HR (p < .01) and had no effect on DAP, and TPRI. The diastolic pressure overshoot of the Valsalva maneuver was attenuated in fixed hypertensives compared to labile (p < .001). Additionally, when the percent changes from control in DAP, MAP, HR and TPRI to sustained handgrip and upright tilt between the two groups were compared, only differences to upright tilt between the two groups were observed. The results of this investigation suggest that upright tilt and the Valsalva maneuver might serve as better predictors of autonomic reflexes in hypertensive patients than the grip test.