AJP - Heart and Circulatory Physiology, Vol 234, Issue 4 392-H398, Copyright © 1978 by American Physiological Society
Comparison of left ventricular free wall and septal diastolic compliance in the dog
R. S. Kent, T. E. Carew, M. M. LeWinter and J. W. Covell
Septal to free wall dimensions are frequently employed for the analysis of
diastolic compliance. However, the diastolic properties of these
anatomically distinct regions of left ventricle are not well characterized.
Regional compliance was studied in eight open-chest anesthetized dogs.
Pairs of 2-mm-diameter piezoelectric crystals were implanted in the left
ventricular free wall or septum 1.38 +/- 0.06 cm apart at a midwall
location 58% +/- 1.9 of the left ventricular endocardial-epicardial or left
ventricular endocardial-right ventricular endocardial distance. Left
ventricular end-diastolic pressure was increased from an average of
8.1-21.0 mmHg, with a resulting average maximum end-diastolic strain of 11%
(end-diastolic (ED) segment length/control ED length). Regional stiffness
was assessed at all sites based on the relationship between left
ventricular end-diastolic pressure and regional strain. Neither strain nor
calculated stiffness coefficients differed significantly among the three
sites. Septal transmural pressure (left ventricular end-diastolic
pressure--right ventricular end-diastolic pressure) was nearly constant as
left ventricular end-diastolic pressure increased during volume infusion
and thus did not account for the observed septal strain.
