Atrial Fibrillation and Incident Myocardial Infarction in the Elderly

Background Atrial fibrillation ( AF ) has been shown to be independently associated with an increased risk of myocardial infarction ( MI ) in a predominantly middle‐aged population; however, this association has not been examined in older populations. Hypothesis AF is associated with MI in older adults. Methods A total of 4608 participants (85% white, 40% male) from the Cardiovascular Health Study without evidence of baseline coronary heart disease were included in this analysis. AF cases were identified during the yearly study electrocardiogram, a self‐reported history of a physician diagnosis, or by hospitalization data. Incident MI was identified using medical records with local and central adjudication. Cox regression was used to compute hazard ratios ( HRs ) and 95% confidence intervals ( CIs ) for the association between AF and incident MI . Results A total of 434 (9.4%) participants had evidence of AF before incident MI . Over a median follow‐up of 12.2 years, a total of 797 (17.3%) participants developed MI . In a multivariable Cox proportional hazards analysis adjusted for socio‐demographics, cardiovascular risk factors, and potential confounders, AF was associated with an increased risk of MI ( HR : 1.7, 95% CI : 1.4‐2.2). A significant interaction was detected by race, with black ( HR : 3.1, 95% CI : 1.7‐5.6) AF participants having an increased risk of MI compared with whites ( HR : 1.6, 95% CI : 1.2‐2.1; P interaction = 0.030). Conclusions AF is associated with an increased risk of MI in a population of older adults.