Systolic time intervals and other cardiovascular changes following leg elevation.
Cardiovascular responses were noninvasively monitored as the legs of 16 supine human subjects were passively elevated to increase return of blood to the heart. Forearm vasodilation occurred promptly as previously observed by Roddie and Shepard (7). Arterial pressure and heart rate were unchanged. Ventricular performance, monitored by systolic-time-interval analysis, was enhanced after a delay of approximately 6 s, an effect which lasted throughout the 40-s leg-elevation period. All affected variables returned to control levels after the legs were lowered. This delayed response could result reflexly from stimulation of receptors in the left atrial region causing an increase in sympathetically mediated contractility or directly from the Frank-Starling mechanism in response to increased left ventricular filling.
D000328:Adult; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007866:Leg; D008297:Male; D009200:Myocardial Contraction; D011187:Posture; D013318:Stroke Volume; D013599:Systole; D013997:Time Factors; D014664:Vasodilation