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Oct 10, 2014

Study Identifies Dangerous Combination of AFib Drugs

When taken together, amiodarone and warfarin can increase stroke risk, finds study.

When taken together, two of the most common drugs used to treat an abnormal heart rhythm increase stroke risk, according to a study published in the Journal of the American College of Cardiology.

Atrial fibrillation or AFib is the most common type of abnormal heart rhythm, affecting more than 2.6 million people in the United States. When it comes to treating AFib, the goals of treatment are often simple: prevent episodes of abnormal heart rhythm and reduce risk for stroke, the most common complication associated with AFib. However, amiodarone, the most effective drug used to prevent AFib episodes, may work against the blood thinner warfarin, which is used to prevent stroke.

The ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial was designed to examine the association between amiodarone and stroke risk in patients with AFib. A total of 18,201 patients participated in the ARISTOTLE trial, 11% of which took amiodarone. After comparing outcomes among study participants, researchers found that patients taking amiodarone and warfarin had significantly increased stroke risk compared to those taking warfarin alone. Investigators also found that a second type of blood thinner called apixaban helped reduce risk of stroke and bleeding compared to patients taking warfarin and/or amiodarone.

Based on these findings, authors conclude that although amiodarone is effective in preventing AFib, it can interfere with the blood thinner warfarin, increasing risk of stroke. Future studies are needed to identify other types of anti-clotting medications that have less interaction with amiodarone, allowing patients to both prevent AFib and reduce risk for stroke. Authors also highlight the safety and efficacy of the anti-clotting drug, apixaban, compared to warfarin. Although warfarin is one of the most common types of blood thinners used to reduce risk of stroke, apixaban may be more effective in reducing stroke risk in AFib patients.
Read the full study in the Journal of the American College of Cardiology

Questions for You to Consider

  • What is atrial fibrillation?

  • Atrial fibrillation is an irregular heart rhythm caused by abnormal, chaotic electrical impulses in the heart’s upper chambers, the atria. These electrical impulses, which interfere with the heart’s natural pacemaker, fire so rapidly the atria cannot beat with a regular rhythm or squeeze out blood effectively. Instead, they merely quiver while the ventricles, the heart’s lower chambers, beat rapidly.
  • Why is someone with atrial fibrillation at risk for a stroke?

  • Normally, blood is constantly flowing through the atria, ventricles and blood vessels. But because blood pools in the quivering atria, it has the chance to congeal into blood clots, which can travel to the brain, blocking blood flow and causing a stroke. That’s why patients with atrial fibrillation must take some form of anti-clotting medication such as aspirin or the blood thinner warfarin (Coumadin).

    Not wanting to take lifelong blood thinners is one of the reasons people have radiofrequency ablation to rid themselves of atrial fibrillation. However, researchers in the new study advised anyone who has already had a stroke to continue taking blood thinners, since atrial fibrillation can return even after a successful radiofrequency ablation procedure.


Bob's Story: Atrial Fibrillation

Learn how Bob Ek and his cardiologist, Scott J. Pollak, MD, FACC, work as a team to manage Bob’s atrial fibrillation.

Kathy Webster is CardioSmart

Kathy Webster was born with a heart defect that contributed to her developing atrial fibrillation. After two open heart surgeries, Kathy is dedicated to living an active and healthy lifestyle.

Marcus McCleery is CardioSmart

An AFib patient, Marcus lost a considerable amount of weight through diet and exercise. He maintains his heart-healthy ways and passes them on to fellow heart patients through volunteer work.

Fatty Acids May Help Prevent Recurrence of Atrial Fibrillation

N-3 polyunsaturated fatty acids found in fish and fish oils help control AFib.

Featured Video

AFib affects more than 3 million people in the United States.

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