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.