What is the hallmark electrocardiographic finding in pericarditis?

• A. ST elevation
• B. Prolonged Q-T interval
• C. Atrial fibrillation
• D. Tall peaked T waves

Answer: (A)

Inflammation of the pericardium creates a global injury current that shows up on ECG as diffuse, upwardly concave ST-segment elevations across many leads, often with simultaneous PR-segment depression. This widespread pattern helps distinguish pericarditis from myocardial infarction, where ST elevations are localized to a specific coronary territory and may have reciprocal changes. Over time, the ST elevations fade and T waves can invert, but the hallmark early finding remains the diffuse, concave ST elevation with PR depression. The other options don’t fit as well: prolonged QT, atrial fibrillation, or tall peaked T waves are not characteristic hallmarks of pericarditis.