ATRIAL-FIBRILLATION IN ACUTE MYOCARDIAL-INFARCTION - A PROSPECTIVE-STUDY BASED ON DATA FROM A CONSECUTIVE SERIES OF PATIENTS ADMITTED TO THE CORONARY-CARE UNIT

Atrial fibrillation (AF) is a common and much-studied arrhythmia in pa tients with acute myocardial infarction (MI). However, documentation o f its occurrence in temporal association with MI has been often neglec ted in the literature; also, its frequent occurrence with mere advance d age, or in the setting of various cardiac conditions or complication s, has prevented the definition of an exact role for AF as a marker or determinant of outcome in patients with MI. The purpose of this study was to evaluate prospectively the frequency of AF (present or occurri ng subsequently) in a consecutive series of patients with MI admitted to the Coronary Care Unit, and to explore for variables associated wit h this arrhythmia; the role of AF in determining major clinical outcom es of the patients was also examined. A large data base of baseline, c linical, laboratory, and patient outcome variables was generated and c ontinuously updated to examine correlates of AF and its possible role in determining prognosis. AF was found in 72 of 517 patients, of whom 58 experienced this arrhythmia anew. Univariate analyses detected a po sitive association of AF with age, pulmonary congestion, left ventricu lar hypertrophy, high admission Killip class, and a large array of com plications including in-hospital mortality. Multivariate analyses show ed, however, that AF correlated weakly with age and strongly with left ventricular hypertrophy and occurrence of ventricular tachycardia, bu t that it was not a determinant of ventricular fibrillation or in-hosp ital mortality.