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Myocardial morphometric changes related to decreased contractility after endotoxin
C M Goddard1, M F Allard, J C Hogg
1Pulmonary Research Laboratory, St. Paul's Hospital, University of British Columbia, Vancouver, Canada.
The American Journal of Physiology
|April 1, 1996
Summary
Sepsis-induced heart dysfunction may stem from blood-borne factors causing structural damage to heart muscle cells (myocytes). This study found endotoxin exposure led to leukocyte infiltration, myocyte damage, and edema, contributing to reduced ventricular contractility.
Area of Science:
- Cardiovascular Physiology
- Sepsis Pathophysiology
- Myocardial Biology
Background:
- Sepsis often causes prolonged myocardial depression, exceeding the duration of known inflammatory mediators.
- The precise mechanisms behind this sustained cardiac dysfunction remain incompletely understood.
Purpose of the Study:
- To investigate the hypothesis that blood-borne factors in sepsis induce structural myocardial changes, leading to decreased ventricular contractility.
- To identify specific structural alterations in the heart muscle following endotoxin administration.
Main Methods:
- An isolated rabbit heart model perfused by a support rabbit was utilized.
- Support rabbits received intravenous endotoxin or vehicle, followed by assessment of cardiac contractility (Emax) and quantitative morphometric analysis of heart tissue.
Main Results:
- Endotoxin infusion significantly decreased ventricular contractility (Emax) by 17% compared to controls.
- Morphometric analysis revealed increased leukocyte-capillary occupancy, structurally abnormal myocytes, and interstitial edema in the endotoxin group.
Conclusions:
- Blood-borne factors associated with sepsis can induce significant myocardial structural damage.
- These structural changes, including leukocyte infiltration and myocyte injury, likely contribute to the prolonged decrease in ventricular contractility observed during sepsis.