Pericarditis ECG Evolution — EECC MCQ

Correct answer: A — Stage 1: diffuse concave ST elevation with PR depression (and reciprocal changes in aVR/V1); Stage 2: ST normalisation with T-wave flattening; Stage 3: diffuse T-wave inversions; Stage 4: normalisation — this evolution occurs over days to weeks

The classic ECG evolution of acute pericarditis progresses through 4 stages: Stage 1 (acute, hours-days): diffuse concave-upward ST elevation in most leads EXCEPT aVR and V1 (which show reciprocal ST depression), with PR segment depression (reflecting atrial subepicardial inflammation); Stage 2 (days): ST segments normalise, T waves begin to flatten — this is the transitional phase (may be mistaken for normal); Stage 3 (1-3 weeks): diffuse T-wave inversions without Q waves (distinguishes from MI where T inversions are territorial); Stage 4 (weeks-months): complete normalisation. Not all patients progress through all stages. The 2025 ESC Myocarditis/Pericarditis Guidelines note that PR depression is the most specific ECG feature for pericarditis (present in ~80%). Widespread ST elevation distinguishes pericarditis from MI (territorial ST elevation with reciprocal changes).

Reference: ESC (2025): Myocarditis/Pericarditis Guidelines