Early diagnosis of pericarditis in acute myocardial infarction.

Pericarditis complicating acute myocardial infarction assumes increasing importance in this era of quantitating infarct size by precordial ST segment mapping. Early recognition of this complication avoids diagnostic and therapeutic errors. In this study we looked for factors that could alert to the early diagnosis of pericarditis, such as ST elevation measured within 24 hours from onset, extent of CPK, LDH, and SGOT elevation, as well as degree of pump dysfunction. ST segment elevation in millimeters on admission seemed to be one factor that was of predictive value in this condition. Pericarditis occurred in three forms: (1) within a few hours from the onset of myocardial infarction and this form seems to carry a high mortality rate; (2) a more common variety occurs within 24 to 72 hours from onset and carries a higher mortality rate than matched controls; and (3) the late syndrome of Dressler's, not observed in our series. Aside from increased incidence of heart failure, other complications of myocardial infarction and the coronary risk factors were not significantly higher in patients with pericarditis. Salicylate treatment offers immediate relief in the majority of patients.