CARDIOVASCULAR ENGINEERING Journal for Extracorporeal Circulation, Assist Devices,Transplantation and Artificial Organs
	Volume 5, 2000, No 1

Myocardial Wall Stress: Evaluation and Management
S. Y. Rabbany, J. Y. Kresh, A. Noordergraaf

Ventricular remodeling via partial left ventriculectomy claims to improve ventricular function in patients suffering from dilated cardiomyopathy. A theoretical basis for surgically reconstructing the left ventricle of the heart is developed together with a detailed analysis of its limitation. This analysis is utilized to quantitate myocardial wall stress and assessing its systolic performance. Given our current understanding of the myocardial structure and the complex force field it generates, the timeliness for revisiting this issue is predicated by the need to better understand the role of myocardial wall stress and chamber mechanics. Ventricular wall stress, as an index of contractility, is evaluated for a number of clinically relevant physiological conditions. A conceptual framework is proposed to systematically investigate the mathematical models used in the calculation of wall stress. Experimental data obtained from animal and human hearts is used to examine the validity of models in which left ventricular pressure is a prerequisite to estimating wall stress. The mathematical constructs used, to date, to calculate stress, in an effort to quantify systolic performance, are flawed. It is the time-varying contractile fiber properties of the myocardium that give rise to the chamber pressure. Hence, an index of myocardial intrinsic force generating capability based upon intraventricular pressure acting as a source of the resulting wall stress is physically indefensible. Ultimately, the insight gained into the cellular / molecular signaling mechanisms underlying the adaptation of the myocardium to altered loading conditions may help clarify the constitutive properties of wall stress as it relates to myocardial contractility and in the process provide a more rational basis for reconstructing the heart.

Key words: ventricular wall stress, remodeling, contractility, partial left ventriculectomy, Batista’s procedure

Address for Correspondence:
Sina Y. Rabbany, Ph.D.
Bioengineering Program
Hofstra University, Hempstead
New York 11549-1330
USA
E-mail: eggsyr@hofstra.edu

Reference:
(CVE. 2000; 5 (1): 3-10)

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