Keywords: pericarditis, acute myocardial infarction, electrocardiography (PubMed Search)
The distinction between pericarditis and acute MI on ECG can often be difficult. Here are a few things that can help rule in acute MI:
1. If the ST-segment elevation is convex upwards in any leads (e.g. appearing like a tombstone) or flat/horizontal across the top, it very strongly favors AMI. Pericarditis should always demonstrate STE that is concave upwards.
2. If ST-segment depression is present in any lead other than aVR or V1, it strongly favors AMI.
3. If PR-depression is present in multiple leads (not just a 2-3 leads, but in MANY) and PR-elevation > 1-2 mm is present in aVR, it favors pericarditis...but only if rules #1 and #2 above are not present.
Be careful about the HPI and description of chest pain...AMI pain is often described as sharp, and in up to 15% it may be described as sharp, pleuritic, or positional in nature, making you think about pericarditis.