Serial Electrocardiographic Changes in Early Post-myocardial Infarction Pericarditis.

A 72-year-old man developed fever and chest pain, accompanied by an increase in C-reactive protein, four days after successful emergency catheter intervention for an acute wide anterior myocardial infarction (MI). A twelve-lead electrocardiogram (ECG) showed marked ST elevation in leads V1-6, I, and aVL, with reciprocal ST depression in leads II, III, and aVF. Although these ECG changes improved by day three, he developed fever and chest pain on day four, and an ECG at this timepoint showed ST elevation in leads II, III, aVF, and mild worsening of the ST elevation in the anterolateral leads, indicating diffuse ST-segment elevation consistent with acute pericarditis. Despite the presence of a typical friction rub, there was no pericardial effusion on an echocardiogram. No elevation of cardiac enzymes was noted. A diagnosis of early post-infarction pericarditis was made, and the patient was successfully treated with acetaminophen and colchicine. Early post-infarction pericarditis (EPIP), albeit rare in the era of emergency catheter treatment, is important because it may indicate a large transmural infarction and must be differentiated from re-infarction. Fever, chest pain, friction rub, ST elevation in the leads distant from the infarct area, recurrence of ST-segment elevation in the infarct area, and increase in inflammatory markers but not cardiac enzymes were crucial for establishing a diagnosis of EPIP.