Dr. Patwari did a great review on differentiating ST elevations associated with pericarditis vs. acute MI. From medical school, I think we can recall many of the classic EKG findings that support pericarditis
- Diffuse ST elevations
- Concave upwards STE
- PR depressions in multiple leads (only reliable seen in viral pericarditis)
- PR elevation in aVR
However, when ruling in pericarditis, one of the most important things we can do is to rule out STEMI. Some factors that support STEMI over pericarditis are:
- STE III> STE II (very strongly favors STEMI)
- STD in leads other than aVR or V1 (suggests reciprocal changes of acute MI)
- Presence of new Q waves
- STE convex upwards or horizontal favors STEMI
The below EKG has the classic findings of pericarditis: diffuse ST elevations, PR elevation in aVR, STE in lead II>lead III. The ST elevation morphology is also concave.
The below EKG shows many of the factors that support MI over pericarditis including: ST elevations in specific coronary artery pattern (inferior leads), ST elevations in lead III>lead II, and reciprocal ST depressions in lateral leads.
And as a reminder of ST elevation morphology… concave STE makes a happy face while convex STE makes a frowny face (or a tombstone). Again, note that STEMI can have all 3 morphologies, while pericarditis will typically only have concave ST elevations. LITFL has a good review of ST elevation morphologies with ST elevation differential (LITFL STE)