STEMI or Pericarditis? How to Tell the Difference
May 6, 2022
Written by Clay Smith
Here are the clues from ECG, echo, and biomarkers that can help distinguish STEMI from pericarditis.
Why does this matter?
Chest pain may mean a lot of things – some dangerous, some not. Both STEMI and pericarditis lead to ST elevation. What are the clues to tell them apart?
STEMI vs pericarditis
This was a case report of a 57 year old man with persistent chest pain, worse with cough, radiating to the back 8 hours after failed streptokinase therapy that was administered the day prior (time from lytic bolus to this episode of pain was 8 hours). He was mildly dyspneic, with otherwise normal vitals and a pericardial friction rub on exam.
There are 3 ways to distinguish STEMI from pericarditis: ECG, echo, and biomarkers (other).
- Usually pericarditis has diffuse concave ST elevation in the precordial and limb leads, with no reciprocal changes or Q waves and upright T waves. There is often diffuse PR depression, except in aVR, which has PR elevation and ST depression (so called ‘knuckle sign’).
- STEMI usually has convex ST elevation in an anatomic distribution, reciprocal changes, T wave inversion, and subsequent Q waves.
- Inferior STEMI may have sinus bradycardia or total AV block (TAVB), as the sinoatrial node, AV node, and his bundle are supplied by the RCA.
- Only 60% of pericarditis cases have pericardial effusion.
- Regional wall motion abnormalities can provide a major clue that STEMI is the culprit rather than pericarditis
- Elevated troponin also favors STEMI, though it could indicate perimyocarditis. Myocarditis may also have wall motion abnormalities and conduction system defects.
- Ultimately, as in this case report, cardiac angiography can help distinguish the two.
- Cardiac MRI can help, and endomyocardial biopsy definitively confirms perimyocarditis.
Conclusion: The patient had elevated troponin, inferior and posterior wall motion abnormalities and minimal pericardial effusion on echo, intermittent – worsening TAVB, and was found to have 99% occlusion of the RCA, which was stented.
Diagnostic Dilemma of Pericarditis Concurrent With ST Elevation Myocardial Infarction. JAMA Intern Med. 2022 Mar 21. doi: 10.1001/jamainternmed.2022.0318. Online ahead of print.