The role of infarction-associated pericarditis on the occurrence of atrial fibrillation

Aims Transient atrial fibrillation is a relatively common arrhythmiain the early phase of acute Q-wave myocardial infarction. However,the role of infarction-associated pericarditis on the genesisof atrial fibrillation is controversial. This study was designedto examine the relative importance of infarction-associatedpericarditis among other clinical variables on the genesis oftransient atrial fibrillation in patients with acute myocardialinfarction. Methods and results Three hundred and ninety-eight patients with acute Q-wave myocardialinfarction were examined carefully by means of auscultation,ECG, two-dimensional echocardiography and haemodynamic measurements.The diagnosis of pericarditis was made on the basis of pericardialrub detected during the first 3 days after admission. At least0·5mm of PQ-segment depression from a TP segment lastingmore than 24h in both limb and precordial leads was considereddiagnostic of PQ-segment depression. Atrial fibrillation waspresent in 76 patients (19%). Sixteen (42%) of 38 patients withPQ-segment depression had atrial fibrillation, whereas 23 (30%)of 77 patients with pericardial rub had atrial fibrillation.Based on ten clinical variables, multivariate analysis was performedto determine the important variables related to the occurrenceof atrial fibrillation. PQ-segment depression (chi-square=4·10,P<0·05) was selected with age (chi-square=10·52,P<0·005), the number of left ventricular segmentswith advanced asynergy (chi-square=7·73, P<0·01)and pericardial effusion (chi-square=7·95, P<0·005)as important factors related to atrial fibrillation. Patientswith PQ-segment depression had a significantly higher pulmonarycapillary wedge pressure than those without it. Conclusion Among patients with infarction-associated pericarditis, thosewith PQ-segment depression represent atrial involvement associatedwith extensive myocardial damage and hence, PQ-segment depressionis one of the clinical signs related to the occurrence of atrialfibrillation in acute Q-wave myocardial infarction.