Diffuse ST elevations with PR depressions across multiple leads is most classic for which condition?

• A. Hyperkalemia
• B. Early repolarization
• C. Acute pericarditis
• D. Myocardial infarction

Answer: (C)

Diffuse ST elevations with PR segment depression across multiple leads point to acute pericarditis. When the pericardium is inflamed, the injury current is global, so many ECG leads show ST elevation rather than a localized pattern. The ST waves are usually concave upward and persist, and the PR segments tend to be depressed in most leads because of atrial involvement from the pericardial inflammation (with PR elevation in aVR as the opposite vector). This combination helps distinguish it from other conditions: hyperkalemia produces tall, peaked T waves and QRS changes rather than diffuse ST elevation; early repolarization can mimic ST elevation but typically lacks PR depression; myocardial infarction shows regional ST elevation with reciprocal changes, not a diffuse pattern. Clinically, pericarditis often presents with pleuritic chest pain that improves when the patient sits up and leans forward.