Acute pericarditis is a clinical inflammatory syndrome. The diagnosis is made when at least two of the following four criteria are present: (1) characteristic chest pain; (2) presence of pericardial friction rub; (3) ECG changes (up to 60% of patients); and (4) pericardial effusion (detected by imaging techniques in up to 60% of patients).1 While it is commonly believed that diffuse ST segment elevation with concomitant ST depression in lead aVR (and V1) and with PR segment depression is typically detected in patients with acute pericarditis, this classic pattern is seen in less than 60% of patients. For example, Imazio et al 2 reported ST segment elevation in only 25% of their cohort of 240 patients with pericarditis. The classic ECG findings are seen mainly in the early phase (stage 1) of acute pericarditis and typically persist up to 2 weeks after symptom onset.3 Later on, ST segment elevation resolves, and T waves become flat or inverted. These changes can persist for several weeks until complete resolution (stage 4).3 However, it should be noted that …