What causes hibernating myocardium?
Hibernating myocardium is the term used to describe a portion of the muscle that makes up the middle layer of heart tissue, the myocardium, that has gone into a state of dormancy due to an inadequate supply of blood. This often occurs as a result of coronary artery disease (CAD).
What does hibernating myocardium mean?
The term “hibernating myocardium” refers to the presence of persistently impaired LV function at rest, due to a reduced coronary blood flow that can be partially or completely restored to normal after revascularization.
How is myocardium hibernating diagnosis?
Hibernating myocardium has also been diagnosed by assessing contractile reserve, usually using echocardiography or magnetic resonance imaging (MRI) and low‐dose dobutamine. A region of the myocardium not initially contracting may contract when stimulated inotropically by low‐dose dobutamine.
Is hibernating myocardium reversible?
‘Hibernating’ myocardium can be defined as reversible left ventricular dysfunction due to chronic coronary artery disease that responds positively to inotropic stress and indicates the presence of viable heart muscle that may recover after revascularization.
What area of the myocardium is most susceptible to ischemia?
Histological evidence indicates that the subendocardial layers of the left ventricle are vulnerable to ischemia: areas of necrosis in the subendocardium are greater than they are in the epicardium in transmural infarction (1) and in coronary insufficiency (2), suggesting that antegrade coronary blood flow in the sub- …
What is Subendocardial myocardium?
A subendocardial infarct results in necrosis exclusively inolving the innermost aspect of the myocardium. Usually a subendocardial infarct is the result of a partially occluded epicardial coronary artery (i.e. NSTEMI).
How can you tell the difference between hibernating and stunned myocardium?
Definitions: Stunned myocardium is viable myocardium salvaged by coronary reperfusion that exhibits prolonged postischemic dysfunction after reperfusion. Hibernating myocardium is ischemic myocardium supplied by a narrowed coronary artery in which ischemic cells remain viable but contraction is chronically depressed.
How long does myocardial stunning last?
It occurs if coronary blood flow was impaired for a brief period of time (5 to 15 minutes). Usually, stunned myocardium persists for hours or days following the re-establishment of coronary blood flow.
What is the difference between stunned and hibernating myocardium?
How long does cardiac stunning last?
How long does it take for stunned myocardium to recover?
In stunned myocardium, contractile function improved significantly at 3 months, without further improvement at 14 months; 61% of the stunned segments improved at 3 months, and 9% improved at 14 months.
What is the pathophysiology of hibernating myocardium?
Hibernating myocardium may begin as repetitive episodes of stunning with normal resting coronary blood flow between episodes but eventually result in a chronic wall motion abnormality with reduced resting blood flow.
What happens to the heart when it hibernates?
Like a bear hibernating through the winter, despite all appearances hibernating heart muscle is not dead, but rather has just assumed a “dormant” state. It no longer functions normally—it does not contract with each heartbeat, and is not contributing to the work of the heart.
What is the treatment of choice for hibernating myocardium?
The therapy of choice for the treatment of hibernating myocardium is revascularization, which can take the form of PCI (angioplasty and/or stenting) or coronary artery bypass surgery.
Is myocardial hibernation associated with benefit from revascularization?
Increasing benefit from revascularization is associated with increasing amounts of myocardial hibernation: a substudy of the PARR‐2 trial. JACC Cardiovasc Imaging. 2009; 2:1060–1068.