Acute pericarditis vs Myocardial infarction on ECG
How to tell Acute pericarditis and Myocardial infarction on ECG apart when a board question makes them look alike.
Pericarditis is diffuse ST elevation plus PR depression; MI is regional ST elevation with reciprocal changes.
Side by side
Pleuritic positional chest pain with diffuse concave ST elevation and PR depression.
Regional ST elevation in a coronary territory with reciprocal ST depression, evolving Q waves, and ischemic symptoms.
Inflamed pericardium and epicardial surface create diffuse injury current and atrial PR-segment changes.
Localized myocardial ischemia/infarction creates territory-based ST changes from a culprit coronary artery.
Diffuse ST elevation, PR depression, friction rub, pain relieved by sitting forward points pericarditis.
Territorial ST elevation, reciprocal depression, Q waves, and wall-motion abnormality point MI.
The trap
ST elevation alone does not decide. Pericarditis shows diffuse concave-up ST elevation across multiple coronary territories with PR segment depression (PR elevation in aVR is highly specific), and no Q waves or reciprocal depression; MI shows territorial ST elevation in one coronary distribution with reciprocal ST depression in opposite leads and evolving Q waves. The clinical context separates further: pericarditis pain improves with sitting forward and worsens with inspiration, often with a friction rub; MI pain is pressure-like with diaphoresis and does not change with position.
Watch it explained
The repair move
When ST elevation appears, ask whether the ECG maps to one artery or the whole pericardial surface.
Try a free question
CoreA patient has sharp pleuritic chest pain improved by sitting forward. ECG shows diffuse concave ST elevations and PR depressions without territorial reciprocal changes. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Acute pericarditis. Acute pericarditis classically causes positional pleuritic pain, diffuse concave ST elevation, and PR depression.
Why the other choices are tempting
- B. STEMI causes regional ST elevation in a coronary territory, often with reciprocal depression.
- C. NSTEMI has troponin elevation without STEMI ECG criteria.
- D. Stable angina is exertional and does not cause diffuse ST elevation/PR depression.
- E. Aortic dissection causes tearing pain and pulse/BP differences rather than diffuse PR depression.
Flashcards
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What is the fastest separator for Acute pericarditis vs Myocardial infarction on ECG?
Pericarditis is diffuse ST elevation plus PR depression; MI is regional ST elevation with reciprocal changes.
What clue should make you choose Acute pericarditis?
Pleuritic positional chest pain with diffuse concave ST elevation and PR depression.
Quick answers
What is the fastest way to tell Acute pericarditis from Myocardial infarction on ECG?
Pericarditis is diffuse ST elevation plus PR depression; MI is regional ST elevation with reciprocal changes.
What is the key clue for Acute pericarditis?
Pleuritic positional chest pain with diffuse concave ST elevation and PR depression.
What is the key clue for Myocardial infarction on ECG?
Regional ST elevation in a coronary territory with reciprocal ST depression, evolving Q waves, and ischemic symptoms.
What is the common trap with Acute pericarditis vs Myocardial infarction on ECG?
ST elevation alone does not decide. Pericarditis shows diffuse concave-up ST elevation across multiple coronary territories with PR segment depression (PR elevation in aVR is highly specific), and no Q waves or reciprocal depression; MI shows territorial ST elevation in one coronary distribution with reciprocal ST depression in opposite leads and evolving Q waves. The clinical context separates further: pericarditis pain improves with sitting forward and worsens with inspiration, often with a friction rub; MI pain is pressure-like with diaphoresis and does not change with position.