Abstract

Objective To investigate the relative incidence, clinical presentation, and prognosis of myopericarditis among patients with idiopathic or viral acute pericarditis.

Design Prospective observational clinical cohort study.

Setting Two general hospitals from an urban area of 300,000 inhabitants.

Patients 274 consecutive cases of idiopathic or viral acute pericarditis between January 2001 and June 2005.

Main outcome measures Relative frequency of myopericarditis. Clinical features at presentation including echocardiographic data (ejection fraction (EF), wall motion score index (WMSI)) and follow-up data at 12 months including complications, results of echocardiography, electrocardiography, and treadmill testing.

Results Myopericarditis was recorded in 40 of 274 (14.6%) consecutive patients. At presentation, the following clinical features were independently associated with myopericarditis: arrhythmias (OR 17.6 95% CI 5.7-54.1; p<0.001), male gender (OR 6.4 95% CI 2.3-18.4; p=0.01), age<40 years (OR 6.1 95% CI 2.2-16.9; p=0.01), ST elevation (OR 5.4 95% CI 1.4-20.5; p=0.013), and a recent febrile syndrome (OR 2.8 95% CI 1.1-7.7; p=0.044). After 12-months follow-up an increase of EF (basal EF 49.6±5.1% vs 12-months EF: 59.1±4.6%; p<0.001) and decrease of WMSI were recorded (basal WMSI 1.19±0.27 vs 12-months WMSI: 1.02±0.09; p<0.001) in patients with myopericarditis with a normalization of echocardiography, electrocardiography, and treadmill testing in 98% of cases. Use of heparin or other anticoagulants (OR 1.1 95% CI 0.3-3.5; p=0.918) and myopericarditis (OR 2.3 95% CI 0.7-7.6; p=0.187) was not associated with an increased risk of cardiac tamponade or recurrences.

Conclusions Myopericarditis is relatively common and shows a benign evolution also in spontaneous cases not related to vaccination.