Acute pericarditis vs STEMI
How to tell Acute pericarditis and STEMI apart when a board question makes them look alike.
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Reciprocal ST depression in opposite leads points to STEMI, not uncomplicated pericarditis.
Side by side
Pleuritic chest pain that improves when leaning forward with diffuse concave ST elevation and PR depression favors acute pericarditis.
Pressure-like chest pain with regional ST elevation in contiguous leads and reciprocal ST depression indicates STEMI.
Inflamed pericardial layers create diffuse epicardial irritation without a single coronary-territory infarct.
Acute coronary artery occlusion causes transmural ischemic injury in one vascular territory.
Troponin is normal or mildly elevated, ECG shows diffuse ST elevation with PR depression in many leads, and bedside echo may show a small pericardial effusion without focal wall-motion abnormality.
High-sensitivity troponin rises above the 99th percentile with dynamic increase, ECG shows ST elevation at least 1 mm in 2 contiguous leads with reciprocal depression, and echo often shows focal wall-motion abnormality.
The trap
Inferior STEMI with early diffuse-appearing ST changes gets mislabeled as pericarditis. Territorial distribution with reciprocal depression in I and aVL or V1 to V3 is the deciding clue and should trigger emergent reperfusion instead of NSAID-only treatment.
The repair move
Next best step: activate the cath lab immediately for primary PCI within 90 minutes, give chewable aspirin 325 mg, start heparin bolus per protocol, and avoid delay for serial ECG-only observation when reciprocal changes identify STEMI.
Try a free question
CoreA 58-year-old woman reports severe substernal pressure for 1 hour with nausea and diaphoresis. BP 94/60 mm Hg and HR 108/min. ECG shows ST elevation in V2 to V5 with reciprocal depression in inferior leads. What is the next best step in management?
Show answer and explanation
Answer: A. Activate primary PCI pathway immediately. Reciprocal depression with contiguous ST elevation indicates STEMI and requires immediate reperfusion.
Why the other choices are tempting
- B. Wrong. Pericarditis treatment is inappropriate when the ECG shows territorial infarction and reciprocal changes.
- C. Wrong. High-risk ACS findings require emergent intervention, not outpatient testing.
- D. Wrong. Nitroglycerin alone does not address coronary occlusion and delays reperfusion.
- E. Wrong. Inflammatory markers do not precede reperfusion decisions in clear STEMI.
Flashcards
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Which ECG feature makes pleuritic chest pain more likely acute pericarditis than infarction?
Diffuse concave ST elevation with PR depression and no reciprocal depression outside aVR and V1.
What ECG pattern supports STEMI even when chest pain could be inflammatory?
Regional ST elevation in contiguous leads plus reciprocal ST depression.
Quick answers
What is the fastest way to tell Acute pericarditis from STEMI?
Reciprocal ST depression in opposite leads points to STEMI, not uncomplicated pericarditis.
What is the key clue for Acute pericarditis?
Pleuritic chest pain that improves when leaning forward with diffuse concave ST elevation and PR depression favors acute pericarditis.
What is the key clue for STEMI?
Pressure-like chest pain with regional ST elevation in contiguous leads and reciprocal ST depression indicates STEMI.
What is the common trap with Acute pericarditis vs STEMI?
Inferior STEMI with early diffuse-appearing ST changes gets mislabeled as pericarditis. Territorial distribution with reciprocal depression in I and aVL or V1 to V3 is the deciding clue and should trigger emergent reperfusion instead of NSAID-only treatment.