Effect of cardiotropic agents on the myocardial dysfunction of hyperdynamic sepsis
Mcdonough, K.H.; Lang, C.H.; Spitzer, J.J.
Circulatory Shock 17(1): 1-19
1985
ISSN/ISBN: 0092-6213 PMID: 4053297 Document Number: 257371
In vitro myocardial performance is impaired in rats during the hyperdynamic, hypermetabolic phase of sepsis. Although the heart in the resting animal generated an elevated cardiac output, the isolated, perfused heart showed a depressed ventricular function curve. In the present studies, interventions to improve contractile function (increased perfusate Ca concentration or perfusion with ouabain) or to decrease Ca availability to the myofibrils (verapamil and tetracaine) were investigated using the isolated perfused working heart. Increasing or decreasing Ca concentration in the perfusion medium had little effect on ventricular performance in the septic group, whereas ouabain enhanced performance by approximately 25%. Addition of verapamil at a dose that caused a minimal decrease in myocardial work (cardiac output .times. peak systolic pressure) in control hearts showed a 20-25% increase in work in the experimental hearts. Increased levels of verapamil caused a greater depression in myocardial performance in the control hearts than in the hearts from septic rats. A multifaceted defect may be present in these hearts with a derangement that can be slightly improved with either ouabain or verapamil. Since neither intervention could completely reverse the myocardial dysfunction in hyperdynamic sepsis, the defect may be due to other factors in addition to Ca availability for contraction.