Which ECG finding is most associated with acute myocardial infarction?

Which ECG finding is most associated with acute myocardial infarction?

• A. ST elevation
• B. T wave inversion
• C. P wave enlargement
• D. U wave prominence

Answer: (A)

ST segment elevation is the hallmark of an acute myocardial infarction, reflecting acute transmural injury to the heart muscle. When the affected area is ischemic, the injury current during repolarization shifts the ST segment away from baseline, producing elevation in the ECG leads over the infarct. This sign defines a STEMI and guides urgent reperfusion therapy. As the infarction evolves, ST elevation can progress to normalization with possible T wave inversion, and in other types of MI you may see different patterns without ST elevation. P wave enlargement indicates atrial enlargement, not acute infarction, and U waves are associated with electrolyte issues or other conditions, not the acute coronary injury.

ST segment elevation is the hallmark of an acute myocardial infarction, reflecting acute transmural injury to the heart muscle. When the affected area is ischemic, the injury current during repolarization shifts the ST segment away from baseline, producing elevation in the ECG leads over the infarct. This sign defines a STEMI and guides urgent reperfusion therapy. As the infarction evolves, ST elevation can progress to normalization with possible T wave inversion, and in other types of MI you may see different patterns without ST elevation. P wave enlargement indicates atrial enlargement, not acute infarction, and U waves are associated with electrolyte issues or other conditions, not the acute coronary injury.