Adult Echocardiography Practice Exam

An aneurysm most often occurs in which type of myocardial infarction?

1. transmural infarction

2. subepicardial

3. subendocardial

4. pericardial

The correct answer is: transmural infarction

An aneurysm most often occurs in a transmural infarction due to the extensive damage to the heart muscle that results from this type of myocardial infarction. A transmural infarction, also known as a full-thickness myocardial infarction, affects the entire thickness of the cardiac wall, leading to a significant loss of contractile tissue. When the myocardium undergoes necrosis from a transmural infarction, the healing process can result in scar tissue formation. This scarred area may not be able to contract effectively, causing the walls of the heart to weaken and stretch. Over time, this can lead to the formation of a ventricular aneurysm, where the weakened area bulges out due to the pressure of the blood inside the heart during contraction. This is particularly common in the left ventricle, which often experiences the greatest stress. Other types of myocardial infarctions, such as subendocardial or subepicardial infarctions, typically involve a localized area of muscle and do not lead to the same degree of wall thinning and stretching as observed in transmural infarctions. Pericardial conditions refer to issues related to the outer lining of the heart and are not directly related to myocardial wall integrity or aneurysm formation.