Serial Electrocardiographic Changes in Early Post-myocardial Infarction Pericarditis

Abstract

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.

Keywords: acute pericarditis; electrocardiography (ecg); friction rub; myocardial infarction; phonocardiography.

Figure 1. Serial twelve-lead electrocardiograms

A) Day one: initial ECG shows wide anterior myocardial infarction (MI) with ST-segment elevation in V1-V6, I, and aVL, along with reciprocal ST depression in leads II, III, and aVF. B) Day three: ECG changes improved after catheterization of the occluded proximal left anterior descending artery. C) Day four: ECG revealed ST-segment elevation (arrows) and PR segment depression in leads II, III, and aVF. ST-segment elevation in the anterior precordial leads had worsened, suggesting diffuse ST elevation consistent with acute pericarditis. D) Day five: ST elevation in the inferior lead started to resolve and the previously inverted T waves in V3-V5 temporarily returned to baseline. E) Day nine: ST elevation in the inferior leads returned to baseline with improvement in ST elevation; however, T wave inversion had recurred.

Figure 2. A phonocardiogram obtained on day three

A phonocardiogram obtained on day three at the bedside at the left fourth interspace with the patient in the supine position. Typical friction rub with presystolic (PS), systolic (S), and early diastolic (D) components were recorded with an electric stethoscope (Eko Devices, Inc. Oakland, California).