AJP - Heart and Circulatory Physiology, Vol 244, Issue 3 370-H377, Copyright © 1983 by American Physiological Society
Canine left ventricular performance during LD50 endotoxemia
R. D. Goldfarb, W. Tambolini, S. M. Wiener and P. B. Weber
Previous reports of the effect of endotoxin shock on cardiac performance
have not achieved uniform results. These discrepancies have possibly been
caused by the use of indices of cardiac performance that may have been
sensitive to altered heart rate or preconditions of cardiac contraction as
well as altered cardiac performance. We tested the hypothesis that,
following a median lethal dose (LD50) of E. coli endotoxin, cardiac
performance would be diminished in nonsurviving animals and maintained in
surviving animals. We elected to employ the analysis of the end-systolic
pressure-diameter relationship (sigma ES) as well as other measurements of
cardiac performance to test this hypothesis. We established that the sigma
ES measurement was independent of increased and decreased afterload and
relatively insensitive to altered heart rate. In the nonsurviving animals,
sigma ES exhibited a marked depression following endotoxin a
administration. In the surviving animals, sigma ES exhibited a
nonsignificant decrease followed by a return toward preendotoxin values.
All other cardiodynamic measurements were uninterpretable due to the marked
changes in heart rate, peripheral vascular function, aortic pressure, and
cardiac output. We conclude that, following endotoxin administration, those
animals that exhibited a diminished myocardial contractility failed to
survive more than 2.5 h postendotoxin, whereas the surviving animals were
able to restore normal cardiac contractility. Thus survival of endotoxin
administration is associated with the maintenance of normal cardiac
contractility.
