ST depression represents?

ST depression represents?

• A. Subendocardial ischemia
• B. Transmural ischemia
• C. Right ventricular strain
• D. Pericardial effusion

Answer: (A)

ST depression indicates subendocardial ischemia. When ischemia affects only the inner layer of the heart wall, the injury current during resting ECG shifts the ST segment downward in the leads that reflect the affected area. This downward or horizontal/downsloping ST depression is a hallmark of partial-thickness ischemia, such as in non-ST elevation myocardial infarction or supply-demand mismatch. In contrast, if the entire wall thickness is involved (transmural ischemia), the typical pattern is ST elevation in the corresponding leads. Other findings like right ventricular strain or pericardial effusion produce different ECG patterns—these do not present with the classic ST depression indicating subendocardial ischemia.

ST depression indicates subendocardial ischemia. When ischemia affects only the inner layer of the heart wall, the injury current during resting ECG shifts the ST segment downward in the leads that reflect the affected area. This downward or horizontal/downsloping ST depression is a hallmark of partial-thickness ischemia, such as in non-ST elevation myocardial infarction or supply-demand mismatch. In contrast, if the entire wall thickness is involved (transmural ischemia), the typical pattern is ST elevation in the corresponding leads. Other findings like right ventricular strain or pericardial effusion produce different ECG patterns—these do not present with the classic ST depression indicating subendocardial ischemia.