Electrocardiographic manifestations and differential diagnosis of acute pericarditis.

Acute pericarditis has many potential etiologies and typically presents as a sharp central chest pain that worsens with recumbency and is relieved by leaning forward. The pathognomonic physical finding of acute pericarditis is the pericardial friction rub, which is usually auscultated along the lower left sternal border. The electrocardiogram (ECG) is a useful, simple tool that may aid in the diagnosis of acute pericarditis. Typical ECG findings include diffuse concave-upward ST-segment elevation and, occasionally, PR-segment depression. ECG changes of both acute myocardial infarction and early repolarization can appear similar to ECG changes of acute pericarditis. However, these conditions can usually be excluded by an accurate history, physical examination and recognition of a few key features on the ECG.