Trends in atrial fibrillation complicating acute myocardial infarction.

Atrial fibrillation (AF) is a common complication of acute myocardial infarction (AMI) and this arrhythmia is associated with increased morbidity and mortality in patients with AMI. Limited information is available, however, about changing, and contemporary, trends in the incidence and death rates associated with AF complicating AMI. We examined the magnitude and impact of AF and the risk of stroke and hospital and long-term death rates in a population-based study of patients hospitalized with AMI. The study population consisted of 7,513 residents of the Worcester, Massachusetts, metropolitan area hospitalized with AMI at all greater Worcester medical centers during 9 biennial years from 1990 to 2005. Overall incidence of AF complicating AMI was 13.3% and rates of AF increased during the most recent years under study. Patients who developed AF were at greater risk for acute stroke (adjusted odds ratio 2.25, 95% confidence interval 1.36 to 3.71) and dying during hospitalization (adjusted odds ratio 1.79, 95% confidence interval 1.46 to 2.19) compared with patients who did not develop AF during hospitalization for AMI. Postdischarge survival was significantly poorer in patients who developed AF. Odds of dying after AF did not change appreciably over the years under study. In conclusion, results of this study in residents of a large New England metropolitan area suggest that AF remains a frequent complication of AMI and is associated with a poor prognosis. Increased surveillance and targeted therapeutic approaches appear warranted for these high-risk patients.