Atrial fibrillation and the risk of sudden cardiac death: the atherosclerosis risk in communities (ARIC) study and cardiovascular health study (CHS)

Abstract

Ojective: It is unknown whether atrial fibrilation (AF) is associated with an increased risk of sudden cardiac death (SCD) in the general population. The objective of this study was to examine the association between incident Af and SCD in 2 population-based cohorts. Research Design & Methods: In the Atherosclerosis Risk in Communities (ARIC) Study we analyzed data from 15439 participants (aged 45-64 years at baseline, 55% women, and 27% black) obtained from baseline (1987-1989) through December 31, 2001. In the Cardiovascular Health Study (CHS), we analyzed data from 5479 participants (aged >_65 years at baseline, 58% women and 15% black) obtained from baseline (first cohort, 1989-1990; second cohort, 1992-1993) through December 31, 2006. SCD was physician-adjudicated and was defined as a sudden, pulseless condition presumed due to a ventricular tachyamhythmia in a previously stable individual. We used multivariable Cox proportional hazards models to assess the association between AF and SCD adjusting for age, sex, race, field center, and baseline cardiovascular risk factors. Results: In ARIC, 894 incident AF and 269 SCD events occurred during follow-up (median, 13.1 years). In participants with and without AF, the crude incidence rates of SCD were 2.89 and 1.30 per 1000 person-years respectively. The multivariable hazard ratio (HR)(95% confidence interval [CI] of AF for SCD was 3.26 (2.17-4.91), P<001. In CHS, 1458 incident AF and 292 SCD events occurred during follow-up (median, 13.1 years). In participants with and without AF, the incidence rates of SCD were 12.00 and 3.82 per 1000 person-years, respectively. The multivariable HR (95% CI) of AF for SCD was 2.34 (1.76-2.91), P<.001 Conclusions: Incident AF is associated with an increased risk of SCD in the general population. Additional research to identify predictors of SCD in patients with AF is warranted.