Initial drop of blood pressure during head-up tilt in patients with cerebrovascular accidents.

OBJECTIVE To investigate cardiovascular responses to orthostatic stress in patients with cerebrovascular accidents (CVA). METHODS Twelve male patients with CVA, 11 healthy elderly and 12 healthy young males participated in the present study. The CVA patients had suffered stroke with hemiplegia at least 11 months prior to the study, their medical conditions were stable, and no subjects were taking medications affecting the cardiovascular system. Heart rate (HR) was determined using RR intervals from the ECG. Stroke volume (SV) was estimated by an impedance method, and cardiac output (CO) was calculated by multiplying SV by HR. Blood pressure (BP) was determined by the auscultatory method. SV, HR, CO and BP were measured every 2 min before and during 7 min of 60-degree head-up tilt (HUT). RESULTS SV decreased and HR increased immediately after starting HUT in all groups. CO in healthy elderly and young subjects immediately decreased during HUT also, and the decrease was sustained throughout the head-up period. However, CO in CVA patients remained constant throughout the experiment. HUT immediately decreased SBP in all groups and the magnitude of initial SBP reduction in CVA patients was greater than that in the other groups. CONCLUSIONS We identified an initial reduction of BP during HUT in CVA patients and the recovery of BP by 3 min of head-up tilt. We emphasize that adjustment to orthostatic stress in CVA patients should be practiced by HUT, as our findings showed that CVA patients maintained physiological orthostatic tolerance except for the initial fall in BP.