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Chronic hibernation and chronic stunning: a continuum.
1Department of Veterans Affairs Western New York Health Care System and the Department of Medicine, University at Buffalo, School of Medicine and Biomedical Sciences, NY 14214, USA. canty@buffalo.edu
Summary
Identifying myocardial viability is crucial for patients with coronary artery disease. Chronic stunning and hibernating myocardium are distinct but related mechanisms of viable, dysfunctional heart muscle.
Area of Science:
- Cardiology
- Physiology
- Pathophysiology
Background:
- Myocardial viability assessment is vital for managing coronary artery disease and left ventricular dysfunction.
- Contractile dysfunction in viable myocardium results from reversible ischemia via multiple mechanisms.
- Distinguishing between chronic stunning and hibernating myocardium is key for treatment decisions.
Purpose of the Study:
- To review pathophysiologic studies on chronic stunning and hibernating myocardium.
- To support the distinct nature of these entities in viable, dysfunctional myocardium.
- To position them as ends of a continuum.
Main Methods:
- Review of basic and clinical pathophysiologic studies.
- Analysis of mechanisms underlying contractile dysfunction in ischemic heart disease.
- Synthesis of evidence on the progression from chronic stunning to hibernation.
Main Results:
- Chronic stunning involves contractile dysfunction with normal resting perfusion.
- Hibernating myocardium exhibits reduced resting flow secondary to contractile dysfunction.
- Repetitive ischemia drives progression from stunning to hibernation.
Conclusions:
- Chronic stunning and hibernating myocardium are distinct pathophysiologic entities.
- These conditions represent different points on a continuum of viable, dysfunctional myocardium.
- Understanding these mechanisms aids in predicting functional recovery after revascularization.