"Acute pericarditis": myocardial enzyme release as evidence for myocarditis.

The relationship between the serial ECG ST-T wave changes held to be characteristic of acute pericarditis and serum cardiac enzyme levels was studied in 18 young men with symptoms of acute infectious disease. Creatine kinase MB enzyme (CK-MB) was detected in 14 patients (78%); its peak levels were as high as 186 U/L during the first days of ST segment elevation. Normal values were only noted during the subsequent T wave inversion stage of the disease. ST segment elevation was more marked (p less than 0.01) and T wave inversions were deeper (p less than 0.01) and more prolonged (p less than 0.05) in the 12 patients with CK-MB levels over 10 U/L than in those with values under 10 U/L. Pericardial friction rub and/or pericardial effusion by echocardiography occurred in only one third of the patients. We conclude that the serial ECG changes of ST segment elevation, with subsequent T wave inversions in connection with acute infection, are caused by acute myocardial injury, myocarditis, as reflected by myocardial enzyme release.