Abstract P102: Resting Heart Rate and Incident Atrial Fibrillation in the Elderly
Background: Alterations in sympathetic tone and/or sinus node dysfunction are common with aging. We hypothesized that older persons with low or high heart rates may represent a population with subclinical conduction abnormalities who are more likely to develop atrial fibrillation (AF).
Methods: A total of 5,226 participants aged 65 years or more (85% white; 42% male) free of baseline AF from the Cardiovascular Health Study were used in this analysis. AF cases were identified during the yearly study electrocardiogram, a self-reported history of a physician diagnosis, or by hospitalization data. Cox regression was used to compute hazard ratios (HR) and 95% confidence intervals (95%CI) for the association between resting heart rate and incident AF. The association by clinically relevant categories (heart rate ≤60 bpm, 60 bpm < heart rate ≤90 bpm (reference), heart rate >90 bpm) and as a continuous variable per 5 bpm decrease were examined.
Results: The mean resting heart rate was 65+/-11 bpm. Over a median follow-up of 12.7 years, a total of 532 (10.2%) participants developed AF. In a multivariable Cox regression analysis adjusted for age, sex, race, education, income, baseline cardiovascular disease, smoking status, systolic blood pressure, diabetes, body mass index, total cholesterol, HDL cholesterol, aspirin use, statins use, antihypertensive and antiarryhthmic medications use, and log(hs-CRP), heart rates ≤60 bpm (HR=1.3, 95%CI=1.1, 1.5), but not >90 bpm (HR=1.1, 95%CI=0.52, 2.3), were associated with an increased risk of AF. Using resting heart rate ≤50 bpm as a cutpoint showed a greater increase in risk of AF ( HR=1.4,95%CI=1.02, 1.8), suggesting a dose response relationship. In a similar model, each 5-bpm decrease in heart rate was associated with a 6% increase in the risk of AF (HR=1.06, 95%CI=1.01, 1.1). A sensitivity analysis excluding participants taking antiarrhythmic and/or heart rate modifying agents did not alter our results. The results were consistent in subgroup analyses stratified by age, sex, race, and baseline cardiovascular disease.
Conclusion: Low resting heart rates were associated with an increased risk of AF in the elderly population enrolled in the Cardiovascular Health Study. Potentially, marked sinus bradycardia in the elderly could be an early marker for increased risk of AF
Author Disclosures: M. Almahmoud: None. E. Soliman: None. W. Oneal: None.
- © 2015 by American Heart Association, Inc.