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Myocardial depression after elective ischemic arrest. Subcellular biochemistry and prevention
The Journal of Thoracic and Cardiovascular Surgery
|April 1, 1979
Summary
Deep hypothermia (18°C) during cardiopulmonary bypass protects cardiac function and biochemistry from ischemic arrest. Profound cooling, unlike moderate hypothermia, preserves sarcoplasmic reticulum and mitochondrial function for full recovery.
Area of Science:
- Cardiovascular Physiology
- Cardiac Surgery
- Biochemistry
Background:
- Global ischemic arrest during cardiopulmonary bypass (CPB) can impair cardiac function.
- Understanding the protective effects of hypothermia on cardiac recovery is crucial for surgical outcomes.
Purpose of the Study:
- To investigate the hemodynamic and cardiac biochemical effects of global ischemic arrest during CPB.
- To evaluate the protective role of different levels of hypothermia and a hyperkalemic hypothermic solution on cardiac function and recovery.
Main Methods:
- Studied hemodynamic and cardiac biochemical effects in animals undergoing CPB with and without ischemic arrest.
- Compared moderate (26°C) and profound (18°C) hypothermia, as well as hypothermic potassium infusion.
- Assessed sarcoplasmic reticulum (SR) calcium binding and mitochondrial oxidative phosphorylation post-ischemia.
Main Results:
- Ischemic arrest significantly reduced left ventricular function (LV dF/dt) and cardiac output.
- Profound hypothermia (18°C) preserved cardiac function and output, nearly equivalent to controls without arrest.
- Deep hypothermia maintained SR calcium binding and mitochondrial function, unlike moderate hypothermia.
Conclusions:
- Profound hypothermia, achieved via surface cooling or hypothermic potassium infusion, allows full recovery of cardiac hemodynamic and biochemical functions within one hour of reperfusion.
- Hypothermia is a key factor in protecting the heart from damage during ischemic arrest in CPB.