Obligatory medical device diagnostics.
- Electrocardiogram (ECG; recording of the electrical activities of the myocardium) – as basic diagnostic [acute stage: ST-segment elevations + PQ depression, positive T wave – see below for further details; with pronounced effusion or pericardial tamponade: low-voltage (decreased height of the QRS complex) and electrical alternans (changing size of the QRS complex)].
- Echocardiography (echo; cardiac ultrasound) – if structural heart disease is suspected [pericardial effusion visible > 50 ml]
- X-ray of the thorax (X-ray thorax/chest), in two planes.
Optional medical device diagnostics – depending on the results of the history, physical examination and mandatory laboratory parameters – for differential diagnostic clarification.
- Computed tomography (CT) of the heart (cario-CT) or magnetic resonance imaging (MRI) of the heart (cardio-MRI) – for further anatomic imaging of the heart [MRI: pericardial inflammation].
Electrocardiographically, four phases of acute pericarditis can be distinguished:
| Stage | ECG description |
| I | ST-segment elevation in multiple leads combined with PQ-segment depression, positive T-wave. |
| II | ST-segment normalization with persistent PQ-segment depression, flattening of the T-wave. |
| III | Isoelectric ST and PQ pathway, generalized negation of the T-wave. |
| IV | normal ECG |