AJP - Heart and Circulatory Physiology, Vol 261, Issue 6 1880-H1888, Copyright © 1991 by American Physiological Society
Myocardial mechanics predict hemodynamic performance during normal function and alcohol-induced dysfunction in rats
J. M. Capasso, P. Li and P. Anversa
Department of Medicine, New York Medical College, Valhalla 10595.
To determine whether mechanical evaluation of muscle tissue removed from
the myocardium can be employed as a direct indicator of cardiac contractile
performance in situ, isometric and isotonic parameters of muscle mechanics
in vitro were correlated with in vivo global functional characteristics of
the same heart. Twelve-month-old animals maintained on standard food and
water were employed as representative of normal cardiac function. Animals
of identical age with left ventricular (LV) dysfunction induced by oral
alcohol (30%) ingestion from 4 to 12 mo were utilized to represent
depressed cardiac performance. Accordingly, 24 h after the establishment of
the hemodynamic profile for a control or experimental heart, the LV
posterior papillary muscle was removed from the same heart and examined
isometrically and isotonically. Least squares regression analysis was
employed to establish a correlation coefficient and P values between
various in vitro and in vivo parameters. Hemodynamic measurements were
performed under chloral hydrate anesthesia and LV pump performance was
evaluated with respect to aortic and ventricular pressures and the rates of
rise and decay of the LV pressure trace. Papillary muscles were evaluated
with respect to timing parameters of the isometric and isotonic twitch, the
first derivative of isometric tension development, and the speed of muscle
shortening at increasing physiologic loads. LV peak rate of pressure rise
and decay were then correlated with the various isometric and isotonic
properties. Myocardial mechanics and hemodynamics revealed depressed
function in the papillary muscles and hearts from alcoholic rats. Moreover,
significant correlations were found between the LV rate of pressure change
(peak +dP/dt and -dP/dt) and both isometric and isotonic twitch
measurements.(ABSTRACT TRUNCATED AT 250 WORDS)
