Q. Investigations process of acute pericarditis?

1) Blood Examination

Erythrocyte sedementaion rate (ESR) may be elevated in tuberculous; collagen and purulent pericarditis. The Dressler's syndrome is associated with leukocytosis and elevated ESR.

2) Electrocardiogram (ECG)

Four stages of evolution of ECG changes may occur.

Stage 1: Acute changes. There is ST-segment elevation with concavity upwards and upright T- waves in all leads except aVR and V1. aVR may show ST-segment depression (Fig. 4.1) PR- segment depression could be seen especially in L2 and lateral chest leads. The absence of reciprocal changes helps in distinguishing from acute myocardial infarction.

Stage 2: Several days later. Resolution of ST-segment and PR-segment to baseline. The T-wave flattens.

Stage 3: T-wave inversion.

Stage 4: T-wave normalizes - may take days to weeks.

3) Chest X-ray

In chest x-ray cardiac silhoutte will be normal unless associated with pericardial effusion in which case there will be cardiomegaly. Evidence of tuberculosis or malignancy in chest X-ray will help in etiological diagnosis.

4) Echocardiography

Pericarditis without effusion does not have any definite echocardiographic features. When the pericarditis lasts longer pericardial thickening may be recognized.

5) Computed Tomography (CT)

Magnetic resonance imaging (MRI) and transoesophageal echocardiography (TEE) have limited application.