Comparison of the biaxial mechanical properties of excised
endocardium and epicardium.
Kang, T., J. D. Humphrey, and F. C. P. Yin.
Department of Medicine, Cardiology, Johns Hopkins Medical
Institutions, Baltimore, MD 21205, Department of Mechanical
Engineering, University of Maryland, Baltimore, MD 21228
APStracts 2:0503H, 1995.
A complete understanding of cardiac mechanics requires knowledge of
the mechanical properties of each of the tissues that comprise the
heart. Data and constitutive relations are available for the
nonlinear multiaxial behavior of epicardium and non-contracting
myocardium, but there have been no comparable results for
endocardium. In this paper, we present biaxial mechanical data for
endocardium and epicardium excised from the same bovine hearts. The
data reveal that these two membranes behave differently: endocardium
exhibits a greater stiffness in the low strain range. Moreover,
quantification of endocardial behavior requires a 7 parameter
polynomial-exponential pseudostrain-energy function w, whereas
epicardium can be described by a 4 parameter exponential w.
Comparison of our current findings with previous results on canine
epicardium reveals further that canine and bovine epicardium behave
similarly, though the latter is more extensible. Thus, there appears
to be marked species differences.
Received 10 July 1995; accepted in final form 2 November 1995.
APS Manuscript Number H633-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 November 95