Which ECG finding is most characteristic of pericarditis?

• A. Normal ECG
• B. Peaked T waves
• C. ST depression in inferior leads
• D. Diffuse ST elevation

Answer: (D)

Diffuse ST elevation on ECG is the hallmark finding in pericarditis. The elevation appears across many leads and is typically concave in shape, reflecting inflammation of the pericardial surface that affects the heart’s outer layer globally rather than a single coronary territory. PR-segment depression often accompanies this pattern, strengthening the diagnosis. This diffuse, widespread change differentiates pericarditis from myocardial infarction, where ST elevations are localized to a specific vascular territory and may have a different contour and reciprocal changes. A normal ECG would not show these widespread elevations, and peaked T waves point more toward hyperkalemia or early ischemia rather than pericarditis. ST depression in inferior leads suggests other pathologies like subendocardial ischemia, not the classic pericarditis pattern.