Pericardial involvement during the course of myocardial infarction. A long-term clinical and echocardiographic study.

STUDY OBJECTIVE This study investigated the long-term course of infarct-related pericarditis and pericardial effusion. Focus was given to the following issues: incidence and timing of pericarditis and pericardial effusion during the acute phase and 3 years follow-up, size, hemodynamic and clinical consequences of effusions, and potential risk of thrombolytic or anticoagulant therapy in patients with pericardial effusion. PATIENTS AND STUDY DESIGN Serial echocardiographic examinations were performed in 192 consecutive patients with first myocardial infarction during the acute phase (day 1, 5, 10, 21) and during 3 years' follow-up (year 1, 2, and 3 after infarction). The follow-up was 100%. Clinical, angiographic, and autopsy data were analyzed. RESULTS Pericardial effusion was detected at least once during serial echocardiographic examinations in 82 of 192 patients (43%). The incidence in different subgroups (with or without thrombolysis, open or closed artery at 3 weeks, infarction in left anterior descending, left circumflex, or right coronary artery perfusion bed) was similar. Most (48%) effusions were first detected on the fifth day, and most (50%) disappeared between days 21 and 365. However, in nine patients, the effusion persisted beyond 1 year (up to 3 years in three patients). Only systolic separation of pericardial layers was detected in 59% of effusions, circular effusion in 3.6% of all effusions. No cardiac tamponade developed. Heart failure or death complicated 49% of infarctions with pericardial involvement and 16% of infarctions without effusion (p < 0.01). Mortality alone was 8% among patients without effusion and 15% among those with more than minimal effusion (not significant). CONCLUSIONS Pericardial effusion can be detected by serial echocardiographic examinations in 43% of myocardial infarctions. It appears during the initial 5 days and disappears slowly during several weeks to several months. Anticoagulant and thrombolytic therapy does not increase the frequency or the size of effusions.