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The hibernating myocardium: implications for management of congestive heart failure
1Division of Cardiology, Northwestern University Medical School, Chicago, Illinois 60611.
Insights
Identifying hibernating myocardium in coronary artery disease (CAD) patients is key. Viable but dysfunctional heart muscle can recover function after revascularization, improving long-term outcomes.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Left ventricular (LV) function is crucial for long-term prognosis in coronary artery disease (CAD).
- Impaired LV function in CAD patients significantly increases mortality risk under medical management.
- LV dysfunction may be reversible, with potential for significant functional improvement after myocardial revascularization.
Purpose of the Study:
- To identify patients with "hibernating" myocardium, characterized by underperfusion, dysfunction, and viability.
- To assess the implications of identifying hibernating myocardium for selecting patients for revascularization.
- To evaluate the potential for LV function improvement and enhanced outcomes in such patients post-revascularization.
Main Methods:
- Utilizing nuclear cardiology techniques such as positron emission tomography (PET) with [18F]fluorodeoxyglucose for metabolism and blood flow assessment.
- Employing thallium-201 and technetium-99m sestamibi scans to evaluate myocardial blood flow and cell membrane integrity.
- Performing 2-D echocardiography with low-dose dobutamine infusion to assess myocardial inotropic reserve.
Main Results:
- Patients with CAD and hibernating myocardium represent a distinct subgroup.
- This subgroup demonstrates potential for substantial improvement in LV function following revascularization.
- Identification of hibernating myocardium is critical for optimizing patient selection for revascularization procedures.
Conclusions:
- Hibernating myocardium is a reversible cause of LV dysfunction in CAD.
- Accurate identification of hibernating myocardium using imaging techniques is essential.
- Revascularization in identified patients can lead to significant improvements in LV function and patient outcomes.
Abstract:
Left ventricular (LV) function is one of the most important determinants of long-term outcome in patients with coronary artery disease (CAD). Patients with normal or near-normal LV function have an excellent prognosis, whereas patients with impaired LV function are at substantial risk of death during medical therapy. It is now apparent that LV dysfunction is not always an irreversible process and that LV function may improve considerably, and even normalize, after myocardial revascularization in a large subset of patients. The identification of such patients with "hibernating" myocardium that is underperfused and dysfunctional, yet viable, has important implications in the selection of patients with LV dysfunction for revascularization procedures. Both nuclear cardiology techniques and 2-D echocardiography can be used for this purpose. The radionuclide techniques include positron emission tomography to assess blood flow and metabolism (using agents such as [18F]fluorodeoxyglucose) and thallium-201 (and possibly technetium-99m sestamibi) to assess blood flow and cell membrane integrity. Alternatively, echocardiographic imaging during low-dose infusions of dobutamine can be used to assess inotropic reserve. The data available to date suggest that patients with CAD in whom hibernating myocardium is largely the cause of impaired LV function constitute a subgroup of patients who may achieve a substantial improvement in LV function and in outcome if identified and treated with revascularization.