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Heart Rhythm. 2017 Dec;14(12):1856-1861. doi: 10.1016/j.hrthm.2017.09.034. Epub 2017 Oct 27.

Atrial ectopy as a mediator of the association between race and atrial fibrillation.

Author information

1
Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California, San Francisco, California; University of Michigan Medical School, Ann Arbor, Michigan.
2
Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California, San Francisco, California.
3
Division of Cardiology, Department of Medicine, Washington University, St. Louis, Missouri.
4
Department of Medicine, Washington University, St. Louis, Missouri.
5
Department of Epidemiology and Prevention, Wake Forest University, Winston Salem, North Carolina.
6
Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon.
7
Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California.
8
Cardiovascular Health Research Unit, Departments of Medicine, Epidemiology, and Health Sciences, University of Washington, Seattle, Washington.
9
Group Health Research Institute, Group Health Cooperation, Seattle, Washington.
10
Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California, San Francisco, California. Electronic address: marcusg@medicine.ucsf.edu.

Abstract

BACKGROUND:

Blacks have a lower risk of atrial fibrillation (AF) despite having more AF risk factors, but the mechanism remains unknown. Premature atrial contraction (PAC) burden is a recently identified risk factor for AF.

OBJECTIVE:

The purpose of this study was to determine whether the burden of PACs explains racial differences in AF risk.

METHODS:

PAC burden (number per hour) was assessed by 24-hour ambulatory electrocardiographic (ECG) monitoring in a randomly selected subset of patients in the Cardiovascular Health Study. Participants were followed prospectively for the development of AF, diagnosed by study ECG and hospital admission records.

RESULTS:

Among 938 participants (median age 73 years; 34% black; 58% female), 206 (22%) developed AF over a median follow-up of 11.0 years (interquartile range 6.1-13.4). After adjusting for age, sex, body mass index, coronary disease, congestive heart failure, diabetes, hypertension, alcohol consumption, smoking status, and study site, black race was associated with a 42% lower risk of AF (hazard ratio 0.58, 95% confidence interval [CI] 0.40-0.85; P = .005). The baseline PAC burden was 2.10 times (95% CI 1.57-2.83; P <.001) higher in whites than blacks. There was no detectable difference in premature ventricular contraction (PVC) burden by race. PAC burden mediated 19.5% (95% CI 6.3-52.5) of the adjusted association between race and AF.

CONCLUSION:

On average, whites exhibited more PACs than blacks, and this difference statistically explains a modest proportion of the differential risk of AF by race. The differential PAC burden, without differences in PVCs, by race suggests that identifiable common exposures or genetic influences might be important to atrial pathophysiology.

KEYWORDS:

Arrhythmia; Atrial fibrillation; Atrial premature beat; Premature atrial contraction; Race

Comment in

PMID:
29110996
PMCID:
PMC5712237
[Available on 2018-12-01]
DOI:
10.1016/j.hrthm.2017.09.034
[Indexed for MEDLINE]
Free PMC Article

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