STEMI is categorized by ST-elevation in 2 or more contiguous leads or new left bundle branch block.

STEMI is categorized by ST-elevation in 2 or more contiguous leads or new left bundle branch block.

• A. True
• B. False
• C. Not sure
• D. Neither

Answer: (A)

STEMI is diagnosed when there is evidence of transmural myocardial injury on the ECG, shown as ST-segment elevation in two or more contiguous leads or a new left bundle branch block. The requirement for two adjacent leads is key because it points to a single coronary territory; it reduces false alarms from isolated, non-specific ST changes. Those contiguous leads reflect the same region of the heart (for example, II, III, and aVF for the inferior wall; V1–V4 for the anterior wall; I, aVL, V5–V6 for the lateral wall). A new left bundle branch block is included because it can mask or mimic ST changes, yet in the right clinical context—presence of ischemic symptoms and compatible ECG changes—it signals acute transmural injury and warrants STEMI treatment. In short, this combination of patterns is the diagnostic trigger, so the statement is true.

STEMI is diagnosed when there is evidence of transmural myocardial injury on the ECG, shown as ST-segment elevation in two or more contiguous leads or a new left bundle branch block. The requirement for two adjacent leads is key because it points to a single coronary territory; it reduces false alarms from isolated, non-specific ST changes. Those contiguous leads reflect the same region of the heart (for example, II, III, and aVF for the inferior wall; V1–V4 for the anterior wall; I, aVL, V5–V6 for the lateral wall). A new left bundle branch block is included because it can mask or mimic ST changes, yet in the right clinical context—presence of ischemic symptoms and compatible ECG changes—it signals acute transmural injury and warrants STEMI treatment. In short, this combination of patterns is the diagnostic trigger, so the statement is true.