Atrial Fibrillation (AFib) is the most common serious abnormal cardiac arrhythmia. Characterized by a rapid and irregular heartbeat, AFib increases the risk of thromboembolic stroke and heart failure. With a prevalence of around 1% in the general population and a heightened prevalence of 6% in people over 60 years old, the number of cases of AFib is predicted to increase dramatically over the coming decades.
When AFib is suspected, palpating the pulse is a good initial test, but EKG showing irregular P waves is needed in order to confirm the diagnosis. While the cause of a significant proportion of AFib cases is unknown, AFib is associated with a variety of underlying pathologies that shouldn’t be missed. Thus, when AFib is suspected, here are a few things that should be on your AFib differential.
It can be easy to focus on rate and rhythm control when a patient is diagnosed with AFib. However, the etiology of AFib can be multifactorial and an indicator of deeper underlying disease in which rate control is not the first line. Categorizing your differential can be helpful in making sure the correct diagnosis can be made. One easy way to do so is to think about AFib in terms of three buckets: cardiac, metabolic, or hyperadrenergic state.
While AFib can appear in a normal heart, it can also be a sign of underlying cardiac dysfunction. Cardiac causes of AFib can be further broken down into three primary categories:
Metabolic causes should also be on your differential as a potential cause of AFib. A detailed clinical and medications history can be an easy way to help patients who are experiencing episodes of AFib or point to an underlying cause. Several metabolic disturbances to keep in mind on your AFib differential are:
Carbon monoxide poisoning
Many medications can cause or exacerbate existing Atrial fibrillation. Some drugs to keep in mind are:
A hyperadrenergic state is a broad bucket that refers to an elevated sympathetic response. While signs of a hyperadrenergic state can be subtle, it is important to keep these causes on your AFib differential as rhythm and rate control might not always be the first-line treatment.
Obstructive sleep apnea
Atrial fibrillation is associated with a variety of causes, ranging across organ systems. While lifestyle changes, rate, and rhythm control are considered first-line therapies, it is important to keep your differential diagnosis broad and screen for other conditions that might cause or exacerbate AFib. Adequately diagnosing and treating these conditions is vital to reducing the burden of AFib.
Chinitz, Jason S., Prashant Vaishnava, Rajeev L. Narayan, and Valentin Fuster. “Atrial Fibrillation through the Years: Contemporary Evaluation and Management.” Circulation 127, no. 3 (January 22, 2013): 408–16. https://doi.org/10.1161/CIRCULATIONAHA.112.120758.
Hooft, Cornelis S. van der, Jan Heeringa, Gerard van Herpen, Jan A. Kors, J. Herre Kingma, and Bruno H. Ch Stricker. “Drug-Induced Atrial Fibrillation.” Journal of the American College of Cardiology 44, no. 11 (December 7, 2004): 2117–24. https://doi.org/10.1016/j.jacc.2004.08.053.
Kanagala, Ravi, Narayana S. Murali, Paul A. Friedman, Naser M. Ammash, Bernard J. Gersh, Karla V. Ballman, Abu S. M. Shamsuzzaman, and Virend K. Somers. “Obstructive Sleep Apnea and the Recurrence of Atrial Fibrillation.” Circulation 107, no. 20 (May 27, 2003): 2589–94. https://doi.org/10.1161/01.CIR.0000068337.25994.21.
Maisel, W. H., J. D. Rawn, and W. G. Stevenson. “Atrial Fibrillation after Cardiac Surgery.” Annals of Internal Medicine 135, no. 12 (December 18, 2001): 1061–73. https://doi.org/10.7326/0003-4819-135-12-200112180-00010.
Marulanda-Londoño, Erika, and Seemant Chaturvedi. “The Interplay between Obstructive Sleep Apnea and Atrial Fibrillation.” Frontiers in Neurology 8 (December 11, 2017): 668. https://doi.org/10.3389/fneur.2017.00668.
Mostafa, Ashraf, Mohamed A. EL-Haddad, Maithili Shenoy, and Tushar Tuliani. “Atrial Fibrillation Post Cardiac Bypass Surgery.” Avicenna Journal of Medicine 2, no. 3 (2012): 65–70. https://doi.org/10.4103/2231-0770.102280.
Nattel, Stanley, Brett Burstein, and Dobromir Dobrev. “Atrial Remodeling and Atrial Fibrillation: Mechanisms and Implications.” Circulation. Arrhythmia and Electrophysiology 1, no. 1 (April 2008): 62–73. https://doi.org/10.1161/CIRCEP.107.754564.
Reddy, Vivek, Wael Taha, Shanker Kundumadam, and Mazhar Khan. “Atrial Fibrillation and Hyperthyroidism: A Literature Review.” Indian Heart Journal 69, no. 4 (2017): 545–50. https://doi.org/10.1016/j.ihj.2017.07.004.
Schotten, Ulrich, Sander Verheule, Paulus Kirchhof, and Andreas Goette. “Pathophysiological Mechanisms of Atrial Fibrillation: A Translational Appraisal.” Physiological Reviews 91, no. 1 (January 2011): 265–325. https://doi.org/10.1152/physrev.00031.2009.
Tarakji, Khaldoun G., Jennifer Silva, Lin Y. Chen, Mintu P. Turakhia, Marco Perez, Zachi I. Attia, Rod Passman, et al. “Digital Health and the Care of the Patient With Arrhythmia.” Circulation: Arrhythmia and Electrophysiology 13, no. 11 (November 1, 2020): e007953. https://doi.org/10.1161/CIRCEP.120.007953.
Tomioka, Tomoko, Kento Fukui, Shuhei Tanaka, Yoshitaka Ito, Hiroki Shioiri, Jiro Koyama, and Kanichi Inoue. “Influence of Atrial Fibrillation on Cardiac Prognosis in Chronic Obstructive Pulmonary Disease.” Indian Heart Journal 71, no. 1 (2019): 7–11. https://doi.org/10.1016/j.ihj.2018.11.009.