In
cardiology
Cardiology () is the study of the heart. Cardiology is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery di ...
, hibernating myocardium is a state when some segments
of the
myocardium
Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall o ...
exhibit abnormalities of contractile function.
These
abnormalities can be visualised with
echocardiography
Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an ec ...
,
cardiac magnetic resonance imaging (CMR), nuclear medicine (PET) or
ventriculography.
Echocardiography: A wall motion abnormality at rest which improves during a low-dose dobutamine stress test is classified as "hibernating myocardium." Low dose dobutamine stimulates contractile function and thus helps to predict functional recovery after revascularization.
Cardiac magnetic resonance: The most frequently used MR
contrast agent
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiop ...
s based on Gd-chelates accumulate in the extracellular space which is increased in scarred myocardium. This leads to a signal increase which can be visualised with the "late gadolinium enhancement technique." This is probably the most accurate way to visualise scarred myocardium. An alternative (or additional) technique with CMR is the use of low dose dobutamine similar to echocardiography.
PET: The finding of a perfusion or metabolic mismatch between PET-FDG and PET-NH
3 is indicative of decreased metabolism. The wall of the affected segments is hypo-, a-, or dyskinetic.
The phenomenon is highly significant clinically because it usually manifests itself in the setting of chronic
ischemia
Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...
, that is potentially reversible by
revascularisation via cardiac catheterization. The regions of myocardium are still viable and can return to normal function. There develops a new steady state between myocardial blood flow (MBF) and myocardial function, MBF reduced and in consequence function is reduced too. The clinical situations where one can expect hibernating myocardium are:
* chronic stable
angina
Angina, also known as angina pectoris, is chest pain or pressure, usually caused by insufficient blood flow to the heart muscle (myocardium). It is most commonly a symptom of coronary artery disease.
Angina is typically the result of parti ...
* unstable angina
* silent ischemia
* after
AMI
See also
*
Stunned myocardium
*
Myocardial scarring
Myocardial scarring is the accumulation of fibrous tissue resulting after some form of trauma to the cardiac tissue. Fibrosis is the formation of excess tissue in replacement of necrotic or extensively damaged tissue. Fibrosis in the heart is ofte ...
References
Ischemic heart diseases
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