Long-term prognosis of patients with paroxysmal atrial fibrillation complicating acute myocardial infarction

The aim of the study was to assess the relationship between paroxysmal atrial fibrillation during acute myocardial infarction and the long-term prognosis of patients after acute myocardial infarction. The incidence of paroxysmal a trial fibrillation among 5803 consecutive hospitalized patients was 9.9% (557/5803). Incidence rose with increasing age (≤59 years, 4.2%), (60–69 years, 10.5%), (≥ 70 years, 16.0%) and was slightly (but not significantly) higher in women (11.0%) than in men (9.6%). The presence of congestive heart failure and mean age represented two major discriminants between patients with paroxysmal atrial fibrillation (70% and 68.6 years) in comparison with their counterparts (35% and 62.3% years). Hospital mortality was significantly higher (25.5%) in patients with paroxysmal atrial fibrillation than in those without (16.2%). However, the effect of paroxysmal atrial fibrillation disappeared when other factors influencing the short term prognosis (i.e. heart failure) were taken into account by a multivariate logistic regression analysis. The covariate adjusted relative odds of in-hospital mortality then fell to 0.82. The 1- and5-year mortality rates were 18.6% and 43.3% in patients with paroxysmal atrial fibrillation as compared to 82% and 25.4% (P <0.001), respectively, in patients free of paroxysmal atrial fibrillation. Using a proportional hazards analysis of mortality through the first quarter of 1988 (average follow-up time, 5.5 years) the net risk of dying among patients with paroxysmal atrial fibrillation complicating the acute myocardial infarction is estimated at 1.28 (90% confidence interval, 1.12–1.46) relative to counterparts free of the complication. Thus the appearance of paroxysmal atrial fibrillation appears to be unrelated to hospital death but independently related to long-term mortality in patients discharged alive, although the magnitude of the association is relatively small compared to the pre-infarction clinical status and the presence of factors directly representing left ventricular dysfunction.