AJP - Heart and Circulatory Physiology, Vol 259, Issue 5 1419-H1426, Copyright © 1990 by American Physiological Society
Comparison between force-velocity and end-systolic pressure-volume characterization of intrinsic LV function
L. P. van der Linden, E. T. van der Velde, A. V. Bruschke and J. Baan
Department of Cardiology, University Hospital of Leiden, The Netherlands.
We reanalyzed experiments in in situ hearts of 16 open-chest anesthetized
dogs, in which two different loading interventions were performed, i.e., an
occlusion of the descending aorta (InP) and a rapid volume infusion (InV).
Previous studies had demonstrated that the end-systolic elastance (Ees) of
the InP was substantially larger than the Ees of the InV suggesting either
a load dependency of Ees as such, or an increase in contractility during
InP. The data were reanalyzed in the light of the muscular pump concept by
plotting peak normalized velocity of circumferential shortening versus a
global representative force approximating the left ventricle by a sphere.
In all but one experiment the points of the two interventions are located
on a single relationship over a very broad range of forces (from 397 to
2,461 g between the control states of experiments and from 602 to 3,278 g
difference between control and highest load within experiments). The
virtual independence of the force-velocity relation (FVR) and the
dependence of the end-systolic pressure-volume relation (ESPVR) on the type
of loading intervention can be ascribed to the fact that the former is
assessed early during ejection and is therefore less influenced by
shortening deactivation and internal resistance than the ESPVR. We conclude
that the FVR offers a more consistent characterization of intrinsic LV
function than the ESPVR.
