Non-ST-Segment Myocardial Infarction Is Associated With

Non-ST-Segment Myocardial Infarction Is Associated With

• A. Partial Thickness Damage To The Myocardium
• B. Transmural Damage
• C. Coronary Artery Disease With Thrombosis
• D. Normal ECG

Answer: (A)

Non-ST-segment elevation MI is defined by subendocardial, or partial-thickness, infarction of the heart muscle. This means the damage involves only the inner portion of the myocardial wall, not the full thickness. Because the necrosis is limited to the subendocardial layer, the ECG classically shows ST-segment depression or T-wave inversion rather than ST-segment elevation. Transmural damage, by contrast, involves the full thickness of the wall and is associated with ST elevation on the ECG, i.e., a STEMI. Coronary artery disease with thrombosis can trigger an MI, but it doesn’t specify the depth of myocardial injury. A normal ECG is not typical for an NSTEMI, since there are usually ECG abnormalities (though they may be non-specific).

Non-ST-segment elevation MI is defined by subendocardial, or partial-thickness, infarction of the heart muscle. This means the damage involves only the inner portion of the myocardial wall, not the full thickness. Because the necrosis is limited to the subendocardial layer, the ECG classically shows ST-segment depression or T-wave inversion rather than ST-segment elevation.

Transmural damage, by contrast, involves the full thickness of the wall and is associated with ST elevation on the ECG, i.e., a STEMI. Coronary artery disease with thrombosis can trigger an MI, but it doesn’t specify the depth of myocardial injury. A normal ECG is not typical for an NSTEMI, since there are usually ECG abnormalities (though they may be non-specific).