Atrial Fibrillation: Updates and Insights

Atrial fibrillation affects 1 in 4 persons across the lifetime of the individual.¹ Prevalence increases as a patient ages.¹   Risk factors for atrial fibrillation include Caucasian race, obesity, smoking, hypertension, diabetes mellitus, and a history of a myocardial infarction or heart failure.^2-6  Several questions may be important in determining the risk of a patient for atrial fibrillation such as, what risk factors precede atrial fibrillation diagnosis, does sleep affect development, is alcohol related to risk, and is cancer a risk marker for atrial fibrillation?   A number of new studies have recently been published that shed light on these questions.

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The Atherosclerosis Risk in Communities was a population-based study with a 25-year follow-up in 2456 patients with atrial fibrillation.   This study assessed cardiovascular risk factors for the development of atrial fibrillation.  Incident atrial fibrillation cases were compared to 6414 matched control subjects from 1987 to 2013.⁷ The prevalence of stroke, myocardial infarction, and heart failure increased in trajectory prior to atrial fibrillation diagnosis.  The pattern was in a form of a J-shaped curve with the lowest incidence approximately 10+ years prior to atrial fibrillation development.  Patients with atrial fibrillation had higher BMIs, obesity, and higher rates of smoking and hypertension.  This study highlights that many risk factors as well as events precede the development of atrial fibrillation, suggesting the greater need for preventative and high quality management of risk factors early in a patients’ history.

In a longitudinal study from the Cardiovascular Health Study and Sleep Heart Health Study, investigators from the University of Michigan performed a longitudinal analysis of a subset of 1131 participants who had sleep duration, efficiency, and latency using polysomnography measured.  They used the apnea-hypopnea-index to assess obstructive sleep apnea (OSA).⁸  Models were adjusted for multiple variables including OSA severity, age, sex, race, site, BMI, smoking status, alcohol use, sleep aid use, diabetes, HTN, CAD, and heart failure.  Sixty percent had mild OSA over the course of 9.8 years of follow-up and of those, 23% developed atrial fibrillation.  Decreased rapid-eye-movement (REM) sleep was associated with increased risk for atrial fibrillation.  This study, although retrospective in nature, suggests that assessing sleep activity, especially in individuals with multiple risk factors for CV disease and/or who are chronically tired, should be undertaken frequently. 

Atrial fibrillation risk has been studied in two recent studies, one published in the Journal of the American College of Cardiology⁹ and the other in JAMA Cardiology.¹⁰  In reviewing prior research (859, 420 persons) over a period of 12 years they found there is no safe level of alcohol intake that reduced the risk of atrial fibrillation.⁹  The risk of atrial fibrillation grew by 8% for each daily alcohol drink.  Furthermore, habitual alcohol intake causes progression from paroxysmal to persistent atrial fibrillation with the potential for increased risk for thromboembolism.  This review suggests that there is no safe level of alcohol intake and abstinence from alcohol for patients with atrial fibrillation should be recommended. 

In a study of approximately 35,000 women ≥45 years of age who were free of atrial fibrillation, cardiovascular disease and cancer at baseline, followed from 1993 to 2013, new-onset atrial fibrillation was found to be associated with an elevated cancer risk.¹⁰  The risk was highest in the first three months after new-onset atrial fibrillation (HR, 3.54; 95% CI: 2.05-6.10) and remained significant past 1 year.  In contrast, women with new-onset cancer had an increased risk of atrial fibrillation in the first three months, but not thereafter.  It is possible that shared risk factors or a common disease pathway are contributing to this risk association.

Atrial fibrillation is a common age-related disorder that predisposes individuals to greater cardiovascular event risk.  It is associated, perhaps, by shared risk factors or common disease pathways with decreased REM sleep and cancer risk in women.  Studies suggest that alcohol increases progression risk of atrial fibrillation.  These studies continue to increase our understanding on an increasingly common arrhythmia.  

References:

1. Lloyd-Jones DM, Wang TJ, Leip EP, et al. Lifetime risk for development of atrial fibrillation: The Framingham Heart Study.  Circulation 2004:110;1042-6
2. Alonso A, Krijthe BP, Aspelund T, et al. Simple risk model predicts incidence of atrial fibrillation in a racially and geographically diverse population: the CHARGE-AF consortium. J Am Heart Assoc.  2013;2:e000102. Doi: 10.1161/JAHA.112.000102.
3. Alonso A, Agarwal SK, Soliman EZ, et al. Incidence of atrial fibrillation in whites and African-Americans: the Atherosclerosis Risk in Communities (ARIC) Study. Am Heart J 2009;158:111-7.
4. Psaty BM, Manolio TA, Kuller LH, et al. Incidence of and risk factors for atrial fibrillation in older adults. Circulation 1997;96:2455-61.
5. Sanoski CA. Prevalence, pathogensis, and impact of atrial fibrillation. Am J Health Syst Pharm.  2016;67(Suppl 5);S11-16.
6. Wang TJ, Parise H, Levy D, et al. Obesity and the risk of new-onset atrial fibrillation. JAMA 2004;292:2471-7.
7. Norby FL, Soliman EZ, Chen LY, et al. Trajectories of cardiovascular risk factors and incidence of atrial fibrillation over a 25-year follow-up. The ARIC Study (Atherosclerosis Risk in Communities). Circulation 2016;134:599-610.
8. Christensen MA, Dixit S, Vittinghoff E, et al. Abstract 733. Decreased REM sleep is associated with higher risk of incident atrial fibrillation. Presented at: 2016 American Heart Association Scientific Sessions. November 12-16, 2016. New Orleans, LA.
9. Voskoboinik A, Prabhu S, Ling L-h, Kalman JM, Kistler PM. Alcohol and atrial fibrillation. A Sobering Review. JACC 2016;68(23):2567-76.
10. Conen D, Wong JA, Sandhu RK, et al. Risk of malignant cancer among women with new-onset atrial fibrillation. JAMA Cardiol 2016;1(4):389-96.