AJP - Heart and Circulatory Physiology, Vol 255, Issue 3 679-H684, Copyright © 1988 by American Physiological Society
Interrelation between end-systolic pressure-volume and pressure-wall thickness relations
J. D. Schipke, J. Alexander Jr, Y. Harasawa, R. Schulz and D. Burkhoff
Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205.
We predicted the shape of the end-systolic pressure-thickness relationship
(ESPTR) by modeling the left ventricle as thick-walled sphere. To test the
validity of the predicted relationships, we then measured the ESPTR over
wide volume ranges in seven isolated blood-perfused canine hearts. Both
simulation and experiments demonstrated that the ESPTR is curvilinear.
However, within a physiological left ventricular systolic pressure range
(80-150 mmHg), the ESPTR was described reasonably well by a straight line.
Within that pressure range, changes in left ventricular contractile state,
assessed by slope changes of the end-systolic pressure-volume relationship,
were associated with almost parallel shifts in the ESPTR. In contrast, in a
low pressure range (less than 80 mmHg), contractility changes were
associated with slope changes of the ESPTR. We conclude that, in general,
there are limitations in the application of ESPTR for assessing left
ventricular contractility, but if the limitations are recognized and
accounted for, then the ESPTR may be useful for assessing contractility
changes in vivo.
