[Quantitative assessment of arterial capacitance in human by noninvasive method].
The purpose of this study was to determine the magnitude of arterial capacitance in human by noninvasive method. In 60 patients (Age: 62.1 +/- 13.4 years) without cardiovascular disease first-pass radionuclide angiography was performed using a digital gamma camera to calculate cardiac output and stroke volume (SV). Systolic interval (ts), diastolic interval (td) and arterial blood pressure were measured using ECG, phonocardiography and sphygmomanometer. We assumed a simple model in which all capacitance (C) lumped into one site with a resistance (R) in parallel to the C. C was calculated by the following basic equations. (Formula; see text) arterial diastolic pressure, E: left ventricular external work. Our results showed: 1) Arterial capacitance ranged from 0.38 ml/mmHg to 2.10 ml/mmHg and more than 60% of stroke volume was pooled in the arterial capacitor during systole. 2) Arterial capacitance fell linearly with age (C = 2.37-0.02 x Age, r = -0.680, p less than 0.001). It is concluded that the capacitor played an important role in arterial circulation.
Akizuki
S
S
Okuyama
Y
Y
Hashimoto
T
T
Karakawa
M
M
D000328:Adult; D001158:Arteries / Q000502:physiology*; D001775:Blood Circulation; D001794:Blood Pressure; D003187:Compliance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D014655:Vascular Resistance; D015646:Ventriculography, First-Pass