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[Chronic ischemic left ventricular dysfunction: myocardial hibernation?]
Insights
Hibernating myocardium, a potentially reversible heart condition, can be identified using various imaging techniques. Revascularization in patients with viable myocardium improves long-term quality of life and reduces mortality.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Context:
- Hibernating myocardium refers to chronic ischemic left ventricular dysfunction, traditionally linked to hypoperfusion.
- This concept is debated, with some suggesting reduced coronary reserve and ischemia/stunning are primary causes of dysfunction.
Purpose:
- To review the diagnostic techniques for detecting hibernating myocardium.
- To evaluate the effectiveness of revascularization in patients with viable myocardium.
Summary:
- Hibernating myocardium is potentially reversible left ventricular dysfunction caused by chronic ischemia.
- Imaging techniques like PET, myocardial scintigraphy, and dobutamine echocardiography detect myocardial viability.
- Dobutamine echocardiography shows higher specificity and positive predictive value compared to isotopic methods.
Impact:
- Coronary revascularization in patients with positive viability tests improves long-term quality of life.
- Revascularization is associated with reduced mortality in patients diagnosed with hibernating myocardium.
Abstract:
Hibernating myocardium is a term which covers chronic ischaemic left ventricular dysfunction which is potentially reversible after revascularisation. Hibernating myocardium is classically associated with chronic hypoperfusion responsible for hypocontraction and cellular degeneration. This "classical" conception has been questioned as some workers emphasise that the reduction in coronary reserve responsible for repeated episodes of ischaemia and stunning could be the main causes of myocardial dysfunction. Position emission tomography (PET), and, most of all, myocardial scintigraphy and dobutamine echocardiography are the most commonly used techniques for detecting hibernating myocardium. Their sensitivity is good but the specificity and positive predictive value of dobutamine echocardiography seems to be better than the isotopic techniques. Structural abnormalities of hibernating myocardium and the delay, which is often long, between revascularisation and improvement, may explain some of the discordances between these techniques. Irrespective of the term used, hibernation or chronic ischaemic left ventricular dysfunction with myocardial viability, the reported data is in favour of coronary revascularisation with improved long-term quality of life and reduced mortality in patients with positive viability tests.