Estimation of aortic distensibility and instantaneous left ventricular volume in living man

A method is presented in this paper for the estimation of aortic distensibility and instantaneous systolic left ventricular volume in living man in the absence of valvular regurgitation. The method is based on a simple, elastic-reservoir-theory, model of the circulatory system and requires no assumption concerning the geometry of the left ventricle. The input data required for this mathematical model consists of stroke volume, an aortic pressure record over an entire cardiac cycle and end diastolic ventricular volume. The procedure developed here for the estimation of aortic distensibility and instantaneous left ventricular volume is very practical from a computational point of view. It is believed that it will yield useful information concerning two clinically important quantities which cannot be measured directly in living man and will facilitate the study of correlations between these quantities and various physiological and pathological states. Results are presented in the paper for six cardiac patients. The requisite data in each case was obtained in the Cardiac Research Laboratory at the Peter Bent Brigham Hospital.