THE ROLE OF INFARCTION-ASSOCIATED PERICARDITIS ON THE OCCURRENCE OF ATRIAL-FIBRILLATION

Aims Transient atrial fibrillation is a relatively common arrhythmia i n the early phase of acute Q-wave myocardial infarction. However, the role of infarction-associated pericarditis on the genesis of atrial fi brillation is controversial. This study was designed to examine the re lative importance of infarction-associated pericarditis among other cl inical variables on the genesis of transient atrial fibrillation in pa tients with acute myocardial infarction. Methods and results Three hun dred and ninety-eight patients with acute Q-wave myocardial infarction were examined carefully by means of auscultation, EGG, two-dimensiona l echocardiography and haemodynamic measurements. The diagnosis of per icarditis was made on the basis of pericardial rub detected during the first 3 days after admission. At least 0.5 mm of PQ-segment depressio n from a TP segment lasting more than 24 h in both limb and precordial leads was considered diagnostic of PQ-segment depression. Atrial fibr illation was present in 76 patients (19%). Sixteen (42%) of 38 patient s with PQ-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 performed to determ ine the important variables related to the occurrence of atrial fibril lation. PQ-segment depression (chi-square=4.10, P<0.05) was selected w ith age (chi-square=10.52, P<0.005), the number of left ventricular se gments with advanced asynergy (chi-square=7.73, P<0.01) and pericardia l effusion (chi-square=7.95, P<0.005) as important factors related to atrial fibrillation. Patients with PQ-segment depression had a signifi cantly higher pulmonary capillary wedge pressure than those without it . Conclusion Among patients with infarction-associated pericarditis, t hose with PQ-segment depression represent atrial involvement associate d with extensive myocardial damage and hence, PQ-segment depression is one of the clinical signs related to the occurrence of atrial fibrill ation in acute Q-wave myocardial infarction.