An ST elevation on an ECG indicates?

• A. A stable angina
• B. A developing or developed myocardial infarction
• C. A non-cardiac chest pain
• D. Ventricular fibrillation

Answer: (B)

ST elevation reflects acute transmural injury of the heart muscle, most often signaling a myocardial infarction that is developing or has already occurred. When a coronary artery is acutely occluded, the injury currents shift the entire ST segment upward in the leads facing the affected region, producing a characteristic elevation. This pattern defines a STEMI and signals the need for urgent reperfusion.

In contrast, stable angina at rest typically does not produce ST elevation (it may have little or no ST change, or ST depression during symptoms). A non-cardiac chest pain would not show ST-segment elevation at all. Ventricular fibrillation is a lethal rhythm disturbance with chaotic electrical activity and no defined ST segments. So the presence of ST elevation most directly indicates a developing or established myocardial infarction.