Adnet, Frédéric

Background— Atrial fibrillation (AF) often coexists with myocardial infarction (MI), yet its prognostic influence is disputed. Prior reports studied the relationship of AF during early hospitalization for acute MI to the risk of death and could not address the timing of AF in relation to the MI (ie, before, during, after). Furthermore, as data come mostly from clinical trials, their applicability to the community is uncertain. The aims of our study were to assess the occurrence of AF among MI patients, determine whether it has changed over time, and quantify its impact and the impact of its timing on mortality after MI. Methods and Results— This was a community-based cohort of 3220 patients hospitalized with incident (first-ever) MI from 1983 to 2007 in Olmsted County, MN. Atrial fibrillation was identified by diagnostic codes and ECG. Outcomes were all-cause and cardiovascular death. Atrial fibrillation before MI was identified in 304 patients, and 729 developed AF after MI (218 [30%] within 2 days, 119 [16%] between 3 and 30 days, and 392 [54%] >30 days post-MI). The cumulative incidence of AF after MI at 5 years was 19% and did not change over the calendar year of MI (the incidence of AF was the same regardless of when the MI occurred). During a mean follow-up of 6.6 years, 1638 deaths occurred. AF was associated with an increased risk of death (hazard ratio [95% confidence interval] 3.77 [3.37 to 4.21]), independently of clinical characteristics at the time of MI and heart failure. This risk differed markedly according to the timing of AF, and was the greatest for AF occurring >30 days post MI (hazard ratio [95% confidence interval] 1.63 [1.37 to 1.93] for AF within 2 days, 1.81 [0.45 to 2.27] for AF between 3 and 30 days, and 2.58 [2.21 to 3.00] for AF >30 days post MI). Conclusions— In the community, AF is frequent in the setting of MI. Atrial fibrillation carries an excess risk of death, which is the highest for AF developing >30 days after MI.

Background— Atrial fibrillation (AF) is a common finding in patients with myocardial infarction (MI). Atrial fibrillation is not generally perceived by clinicians as a critical event during the acute phase of MI; however, its prognostic influence in MI remains controversial. Furthermore, contradictory data exist concerning the risk of death according to AF timing. This article, a systematic review and first meta-analysis, aims to quantify the mortality risk associated with AF in MI patients and its timing. Methods and Results— A comprehensive search of several electronic databases (1970 to 2010; adults, any language) identified MI studies that evaluated mortality related to AF. Evidence was reviewed by 2 blinded reviewers with a formal assessment of the methodological quality of the studies. Adjusted odds ratios were pooled across studies using the random-effects model. The I 2 statistic was used to assess heterogeneity. In the 43 included studies (278 854 subjects), the mortality odds ratio associated with AF was 1.46 (95% confidence interval, 1.35 to 1.58; I 2 =76%; 23 studies). This worse prognosis persisted regardless of the timing of AF; the odds ratio of mortality for new AF with no prior history of AF was 1.37 (95% confidence interval, 1.26 to 1.49), I 2 =28%, 9 studies), and for prior AF was 1.28 (95% confidence interval, 1.16 to 1.40; I 2 =24%; 4 studies). The sensitivity analysis of new AF studies adjusting for confounding factors did not show a decrease in risk of death. Conclusions— Atrial fibrillation is associated with increased risk of mortality in MI patients. New AF with no history of AF before MI remained associated with an increased risk of mortality even after adjustment for several important AF risk factors. These subsequent increases in mortality suggest that AF can no longer be considered a nonsevere event during MI.