An investigation of endocardial viability ratio in myocardial failure following prolonged hemorrhagic shock.

Previous work has documented prolonged survival in dogs subjected to hemorrhagic shock when intra-aortic balloon counter-pulsation (IABC) was instituted in the presence of a 25%-50% reduction in the slope of the left ventricular function curve. Little benefit was noted in the presence of a 75% reduction in slope. In this study, myocardial failure was created in ten dogs by varying periods of hemorrhagic shock. The Endocardial Viability Ratio (EVR) was selected as a method of assessing coronary subendocardial perfusion and was evaluated as a potential method of selecting patients with myocardial failure most likely to benefit from IABC by noting the correlation between EVR and the slope of a simultaneously constructed left ventricular function curve. A significant correlation (r equals .72, p smaller than .001) was noted. The data suggest that a major factor in myocardial failure following hemorrhagic shock is deficient subendocardial coronary perfusion. Variability in data points would make selection of patients on the basis of EVR difficult.