EKG Criteria in Pericarditis

Inflammation of the pericardium, usually after a viral infection, presenting classically with chest pain that improves when leaning forward, tachycardia, and dyspnea. Can be associated with a friction rub or pericardial effusion. 

In pericarditis four stages can be distinguished on the ECG:

• stage I: ST elevation in all leads. PTa depression (depression between the end of the P-wave and the beginning of the QRS- complex). ST elevation should be present in all leads except aVR, V1, III. 
• stage II: pseudonormalisation (transition)
• stage III: inverted T-waves
• stage IV: normalisation

Sources:
​ECGpedia; http://en.ecgpedia.org/index.php?title=Pericarditis