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Murine Isolated Heart Model of Myocardial Stunning Associated with Cardioplegic Arrest
Published on: August 6, 2015
Post-ischaemic myocardial dysfunction (stunning) results from myofibrillar oedema
T Bragadeesh1, A R Jayaweera, M Pascotto
1Division of Cardiovascular Medicine, Oregon Health and Science University, Portland, Oregon 97239, USA.
Heart (British Cardiac Society)
|July 20, 2007
Summary
Myocardial stunning from ischemia-reperfusion causes myocyte swelling and myofibrillar edema, impairing heart muscle function. As edema resolves, cardiac function recovers, indicating a reversible process.
Area of Science:
- Cardiovascular Physiology
- Cellular Biology
- Pathophysiology
Background:
- Myocardial stunning is a post-ischemic dysfunction.
- The underlying mechanisms of myocardial stunning require further elucidation.
Purpose of the Study:
- To investigate the role of myofibrillar edema in myocardial stunning.
- To test the hypothesis that myocardial stunning is caused by myofibrillar edema.
Main Methods:
- Experiments were conducted on anesthetized pigs.
- Myocardial stunning was induced via ischemia-reperfusion or mast cell degranulator.
- Circumferential left ventricular (LV) strain was measured using tagged MRI.
- Myocardial water content (MWC) and interfilament lattice distance (d) were quantified post-mortem and via electron microscopy (EM).
Main Results:
- Increased MWC and 'd' were observed in stunned myocardium.
- A significant inverse correlation was found between myocardial strain (E(cc)) and MWC (r = -0.81).
- A strong inverse correlation was noted between E(cc) and 'd' (r = -0.90).
- EM confirmed significantly lower 'd' in normal compared to stunned myocardium (p<0.001).
Conclusions:
- Ischemia-reperfusion induces myocardial edema and myocyte swelling.
- Myofibrillar edema increases interfilament lattice distance, impairing myosin-actin interaction and force generation.
- Resolution of myocardial edema correlates with improved myocyte function and recovery from stunning.
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