Understanding Obesity’s Role in Atrial Fibrillation

A recent study published in the Journal of the American College of Cardiology explored whether new-onset AF risk could be reduced in severely obese individuals following weight loss via bariatric surgery.⁹ A group of 2000 patients who underwent the surgery was compared to a group of 2021 patients who received treatment as usual. The results showed that the surgery group had a 29% lower risk of developing AF than the control group, and younger patients and those with high diastolic blood pressure had a greater benefit than those who were older or had low diastolic blood pressure, respectively.

“This could be a very key management strategy among younger adults with the severest of obesity to reduce the risk of the future morbidity and mortality associated with AF development,” noted Dr Michos.

Improving Outcomes With Exercise & Management of Comorbid Conditions

Moderate-intensity physical activity can reduce AF risk by 30% in addition to weight loss, though high-intensity exercise may actually boost AF risk, Dr Michos stated.¹⁰ “There is a graded, inverse relationship between high levels of cardiorespiratory fitness and incident AF, which is even more notable among obese patients.” Findings reported in 2015 revealed that overweight and obese AF patients who improved their level of fitness by ≥2 METs had a steeper reduction in AF burden and symptom severity, as well as rates of recurrence, vs those whose fitness improvement was <2 METs.¹¹

Dr Michos recommends that her patients engage in regular moderate-intensity exercise, such as brisk walking for 40 to60 minutes daily, which most patients with obesity should be able to tolerate. She also suggests that they track their step counts. “Brisk walking in particular has a low rate of musculoskeletal injury and no known excess risk of severe cardiac events—it is an activity that can be initiated by almost all sedentary adults.”

Along with weight loss, Dr Boyle added that the “management of common comorbid conditions like cardiometabolic risk factors have been shown to benefit AF in terms of less frequency and persistence.”² “Cardiologists often tend to focus just on the arrhythmia, and we haven’t been as active as we should be in having these comorbid conditions treated, managed, and actively followed.”

Sleep apnea is one such condition that is linked with both obesity and a higher AF risk, said Dr Michos, and treating it with continuous positive airway pressure (CPAP) machines has been found to prevent AF recurrence after cardioversion or ablation.² Treating high blood pressure also reduces AF risk as well as the risk of stroke.²

“If we’re not going to actively manage these conditions, we need to involve other clinicians who will—for example, endocrinologists, internists, or other cardiologists,” advised Dr Boyle.

References

1. US Centers for Disease Control and Prevention. Adult obesity facts. https://www.cdc.gov/obesity/data/adult.html. Updated September 1, 2016. Accessed December 19, 2016.
2. Nalliah CJ, Sanders P, Kottkamp H, Kalman JM. The role of obesity in atrial fibrillation. Eur Heart J. 2016;37(20):1565-1572. doi: 10.1093/eurheartj/ehv486.
3. Wong CX, Sullivan T, Sun MT, et al. Obesity and the risk of incident, post-operative, and post-ablation atrial fibrillation. A meta-analysis of 626,603 individuals in 51 studies. JACC Clin Electrophysiol. 2015;1(3):139-152. doi:10.1016/j.jacep.2015.04.004.
4. Guijian L, Jinchuan Y, Rongzeng D, Jun Q, Jun W, Wenqing Z. Impact of body mass index on atrial fibrillation recurrence: a meta-analysis of observational studies. Pacing Clin Electrophysiol. 2013;36(6):748-756. doi:10.1111/pace.12106.
5. Sandhu RK, Ezekowitz J, Andersson U, et al. The ‘obesity paradox’ in atrial fibrillation: observations from the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial. Eur Heart J. 2016;37(38):2869-2878. doi: 10.1093/eurheartj/ehw124.
6. Rosenberg MA, Manning WJ. Diastolic dysfunction and risk of atrial fibrillation. Circulation. 2012;126(19):2353-2362. doi:10.1161/CIRCULATIONAHA.112.113233.
7. Al-Rawahi M, Proietti R, Thanassoulis G. Pericardial fat and atrial fibrillation: epidemiology, mechanisms and interventions. Int J Cardiol. 2015;15(195):98-103. doi:10.1016/j.ijcard.2015.05.129.
8. Pathak RK, Middeldorp ME, Meredith M, et al. Long-term effect of goal-directed weight management in an atrial fibrillation cohort: a long-term follow-up study (LEGACY). J Am Coll Cardiol. 2015;65(20):2159-2169. doi:10.1016/j.jacc.2015.03.022.
9. Jamaly S, Carlsson L, Peltonen M, Jacobson P, Sjöström L, Karason K. Bariatric surgery and the risk of new-onset atrial fibrillation in Swedish obese subjects. J Am Coll Cardiol. 2016;68(23):2497-2504. doi:10.1016/j.jacc.2016.09.940.
10. Mozaffarian D, Furberg CD, Psaty BM, Siscovick D. Physical activity and incidence of atrial fibrillation in older adults: the Cardiovascular Health Study. Circulation. 2008;118(8):800-807. doi:10.1161/CIRCULATIONAHA.108.785626.
11. Pathak RK, Elliott A, Middeldorp ME, et al. Impact of CARDIOrespiratory FITness on arrhythmia recurrence in obese individuals with atrial fibrillation: the CARDIO-FIT study. J Am Coll Cardiol. 2015;66(9):985-996. doi:10.1016.j.jacc.2015.06.488.