BACKGROUND Change in cardiac preload caused by mild hypovolemia can alter left ventricular ejection time (LVET) without noticeable change in blood pressure (BP). Previously our group has explored a novel method of LVET monitoring using a noninvasive finger photoplethysmographic pulse oximetry wave form. The current study investigated the ability of photoplethysmographic pulse oximetry wave form...

Starr's formula for deriving stroke volume from pulse pressure, diastolic pressure, and age has been tested experimentally in a group of miscellaneous hospital patients. Nearly simultaneous measurements of stroke volume by the direct Fick method and of brachial arterial pressure by direct puncture were analyzed. The measured stroke volume frequently differed considerably from the values calcula...

Background. Although the existence of myocardial mechanoelectrical feedback is well established, the mechanism of arrhythmia induction by ventricular dilatation or stretch remains insuffliciently defined. In particular, controversy exists when comparing the arrhythmogenic potential of chronic versus acute myocardial stretch. Also, assessment of cellular electrophysiological effects of myocardia...

Recently, oscillometric devices have been developed that can measure blood pressure in the extremities and analyze pulse volume record. On the basis of the extremity pulse volume record, these devices can automatically determine three types of simply measured pulse wave velocity (PWV) (brachial PWV: heart to right upper arm; R-PWV: right upper arm-right ankle; and L-PWV: right upper arm-left an...

Earlier studies from this laboratory (1, 2, 3) have shown that the intravenous administration of 500 to 1500 cc. of fluids, at rates ranging from 9 to 125 cc. per minute, results in appreciable increases in plasma and blood volumes. Significant changes in cardiovascular dynamics did not occur at rates of injection under 20 cc. per minute; administration of fluids intravenously at faster rates r...

Objective To investigate the phenotypic relationships between aortic stiffness and left ventricular (LV) stroke volume (SV) and modes of deformation (longitudinal LD and radial -RD) at rest and stress, with preserved and compromised contractile capacity. Background Increased aortic stiffness, measured by pulse wave velocity (PWV), is linked to a range of cardiovascular (CV) risk factors and act...

Exercise markedly influences pulse wave morphology, but the mechanism is unknown. We investigated whether effects of exercise on the arterial pulse result from alterations in stroke volume or pulse wave velocity (PWV)/large artery stiffness or reduction of pressure wave reflection. Healthy subjects (n = 25) performed bicycle ergometry. with workload increasing from 25 to 150 W for 12 min. Digit...

The basolateral amygdala (BLA) has substantial effects on the neuronal transmission and synaptic plasticity processes through the dentate gyrus. Orexin neuropeptides play different roles in the sleep/wakefulness cycle, feeding, learning, and memory. The present study was conducted to investigate the function of the orexin receptors of the BLA in the hippocampal local interneuron circuits. For t...

OBJECTIVE Manual assessment of radial arterial pulse character remains an important determinant of physiological status in military and civilian casualties. This study hypothesized that changes in radial pulse character and mental status (presyncopal symptoms) in humans occur only during the later stages of progressive reductions in central blood volume in close association with systolic blood ...