Abnormal heart rhythms: How do different medications stack up?

The Bottom Line

  • Atrial fibrillation (Afib), is a condition that causes the heart to beat irregularly and increases the risk of stroke.
  • Different types of blood thinners are used to treat Afib: vitamin K antagonists (e.g., warfarin), non-vitamin K antagonists (NOACs – e.g., apixabandabigatranrivaroxabanedoxaban), and aspirin. 
  • Warfarin reduces the risk of stroke and blockage of blood vessels by blood clots compared with aspirin, with no increased risk of major bleeding.
  • Compared to warfarin, non-vitamin K antagonists (NOACs) are more effective at lowering the risk of stroke/blockage of blood vessels and major bleeding.
  • Speak with your health care provider about which treatment option is best for you. 

When you have atrial fibrillation—or “Afib”—your heart’s normal rhythm is out of whack (1). So, your heart may quiver and flutter, but not in a good way.

If you suffer from Afib, you’re not alone. Afib is the most common type of abnormal heart rhythm in adults (2-6), affecting 350,000 Canadians (7) and around 1 in 4 adults aged 40 years old and over (3;8). As the world’s population ages, this condition is expected to become even more commonplace (3;9-11).

During Afib, the heart often beats faster than normal, with the top half of the heart beating out of sync with the bottom half (1). This means that blood doesn’t move in and out of your heart as it should. Although Afib is usually not life-threatening, it sometimes requires emergency medical treatment (1-3;12). It can also lead to complications—people with Afib are at higher risk of stroke and potentially dangerous blood clots deep in the veins or lungs. This increased risk is thought to occur because of changes in blood flow, blood composition, or the blood vessel walls (3;13).

People with Afib are often treated with “blood thinners” to reduce the chance that they will develop a blood clot. Older types of blood thinners include aspirin, as well as vitamin K antagonists such as warfarin. Newer to the arsenal are non-vitamin K antagonists (NOACs), including dabigatran, rivaroxaban, apixaban, and edoxaban (2;14).

Each of type of blood thinner has their own risks and benefits. But, which ones work best to prevent stroke and blood clots and how safe are they? A recent systematic review explored the evidence (2;3).

What the research tells us

Overall, the review found that warfarin can reduce the risk of stroke/blockage of blood vessels by blood clots and death in people aged 65 years old and over with Afib, compared with aspirin or no treatment. What’s more, there was no increased risk of major bleeding.

Older adults taking the newer NOACs seemed to fare even better than those taking warfarin. As a group, NOACs were associated with a lower risk of stroke and blood clots, as well as a reduced risk of major bleeding (2;3) and death (2), compared to warfarin. That said, these findings may differ depending on the person and NOAC that is used—while some NOACs were superior, others were on par with warfarin in terms of stroke/blood clots and major bleeding (2).

An important consideration to keep in mind when it comes to NOACs, is that they may not be for everyone. As with any medication, factors such as your health status, other medications you take, and more play a role in what your health care provider is able to prescribe. Price is also a factor, as NOACs tend to be more expensive than warfarin.

Although Afib can send your heartbeat into temporary chaos, this chaos doesn’t need to wreak havoc on your life. Newer blood thinners may be a safer and more effective way to ease your fluttering heart and the complications it brings. Speak with your health care provider about which treatment option is best for you, and before making any changes to your medications. 

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  1. Mayo Clinic. Atrial fibrillation. [Internet] 2018. [cited May 2019]. Available from https://www.mayoclinic.org/diseases-conditions/atrial-fibrillation/symptoms-causes/syc-20350624 
  2. Bai Y, Guo SD, Deng H, et al. Effectiveness and safety of oral anticoagulants in older patients with atrial fibrillation: A systematic review and meta-regression analysis. Age Ageing. 2018; 47(1):9–17. doi: 10.1093/ageing/afx103.  
  3. Bruins Slot KM, Berge E. Factor Xa inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in patients with atrial fibrillation. Cochrane Database Syst Rev. 2018; (3):CD008980. doi: 10.1002/14651858.CD008980.pub3. 
  4. Go AS, Hylek EM, Philips KA, et al. Prevalence of diagnosed atrial fibrillation in adults. National implications for rhythm management and stroke prevention: The AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. JAMA. 2001; 285: 2370–2375. doi: 10.1001/jama.285.18.2370. 
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    doi: 10.1378/chest.11-2888.
  6. Sun GZ, Guo L, Wang XZ, et al. Prevalence of atrial fibrillation and its risk factors in rural China: A cross-sectional study. Int J Cardiol. 2015; 182:13–17. doi: 10.1016/j.ijcard.2014.12.063.
  7. Heart and Stroke. Atrial fibrillation. [Internet] 2018. [cited May 2019]. Available from https://www.heartandstroke.ca/heart/conditions/atrial-fibrillation
  8. Lloyd‐Jones DM, Wang TJ, Leip EP, et al. Lifetime risk for developing atrial fibrillation: The Framingham Heart Study. Circulation. 2007; 110:1042–1046.
  9. Wattigney WA, Mensah GA, Croft JB. Increasing trends in hospitalisation for atrial fibrillation in the United States, 1985 through 1999: Implications for primary prevention. Circulation 2003; 108:711–716.
  10. Miyasaki Y, Barnes ME, Gersh BJ, et al. Secular trends in incidence of atrial fibrillation in Olmsted County, Minnesota, 1980 to 2000, and implications on the projection for future prevalence. Circulation. 2006; 114:119–125.
  11. Krijthe BP, Kunst A, Benjamin EJ, et al. Projections on the number of individuals with atrial fibrillation in the European Union, from 2000 to 2060. Eur Heart J. 2013; 34:2746–2751. doi: 10.1093/eurheartj/eht280.
  12. Wolf PA, Abbott RD, Kannel WB. Atrial fibrillation as an independent risk factor for stroke: The Framingham Study. Stroke. 1991; 22:983–938. doi: 10.1161/01.str.22.8.983.
  13. Watson T, Shantsila E, Lip GYH. Mechanisms of thrombogenesis in atrial fibrillation: Virchow’s triad revisited. Lancet. 2009; 373:155–166. doi: 10.1016/S0140-6736(09)60040-4.
  14. Lane DA, Wood K. A patient’s guide to taking the non-vitamin K antagonist oral anticoagulants (NOACs) for atrial fibrillation. Circulation. 2015; 131(16):e412-e415. doi: 10.1161/CIRCULATIONAHA.114.012808. 

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