Pericarditis

Acute pericarditis is a type of pericarditis (inflammation of the sac surrounding the heart, the pericardium) usually lasting less than 6 weeks. It is by far the most common condition affecting the pericardium.

Typical ECG changes in acute pericarditis includes:

• stage 1 - diffuse, positive, ST elevations with reciprocal ST depression in aVR and V1. Elevation of PR segment in aVR and depression of PR in other leads especially left heart V5, V6 leads indicates atrial injury.
• stage 2 - normalization of ST and PR deviations
• stage 3 - diffuse T wave inversions (may not be present in all patients)
• stage 4 - ECG becomes normal OR T waves may be indefinitely inverted

The two most common clinical conditions where ECG findings may mimic pericarditis are acute myocardial infarction (AMI) and generalized early repolarization.