An arrhythmia is a problem with the speed or rhythm of your heartbeat. Atrial fibrillation (afib) is the most common type of arrhythmia and affects at least 2.7 million people in the United States. Left untreated, afib can lead to life-threatening complications, such as blood clots and strokes.
“Afib is a common disorder and occurs in about 5 percent of people over age 65,” says Bradley Knight, MD, professor of cardiology at Northwestern University in Chicago. “There are many causes of afib, but aging and obesity are the two most prevalent causes right now.”
Better care for patients with afib is the goal of treatment guidelines for doctors. Working together, the American College of Cardiology, American Heart Association, and the Heart Rhythm Society updated the 2014 treatment guidelines for afib. The 2019 Update was published simultaneously in three journals: Journal of the American College of Cardiology, Circulation, and Heart Rhythm.
A major update has to do with the use of anticoagulants, sometimes referred to as blood thinners. These drugs are a standard treatment for afib, and work by reducing the likelihood of blood clots forming, which in turn helps to prevent strokes. Newer non–vitamin K oral anticoagulants (NOACs) are now favored over the older drug warfarin.
What’s New in the 2019 Afib Guidelines
“In the 2014 guidelines, warfarin and NOACs were considered equivalent,” says Craig T. January, MD, PhD, professor of cardiovascular medicine at the University of Wisconsin in Madison and chair of the writing committee. “In the 2019 guidelines, NOACs are preferred over warfarin because they have less risk of bleeding and may be more effective at preventing blood clots than warfarin.”
Warfarin was approved in 1954 by the U.S. Food and Drug Administration (FDA) to help prevent strokes in patients with afib. Since 2010, four NOACs have been approved by the FDA to treat afib, including Pradaxa (abigtran), Xarelto (rivaroxaban), Eliquis (apixaban), and Savaysa (edoxaban).
There were three areas that the writing committee considered when updating the guidelines, noted Dr. January:
- Safety Prior scientific studies showed that most of the NOACs have a lower bleeding risk compared with warfarin. The safety data had the strongest evidence and was the main consideration for preferring NOACs over warfarin.
- Efficacy With regard to the prevention of blood clots and stroke, some research has suggested that NOACs may have a lower incidence of stroke. But this evidence was less convincing than the safety data.
- Mortality There was no data to suggest that favoring warfarin or NOACs would lower mortality, so this consideration did not play a big role in the guideline update.
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What the Updated Guidelines Mean for You
“In the past, when patients were diagnosed with afib, they were often given the choice of warfarin or the newer oral anticoagulants,” says Dr. Knight. “Today, doctors generally prefer to start newly diagnosed afib patients on NOACs because they are more convenient and don’t require regular blood work.”
In contrast, patients on warfarin typically get their blood drawn at least once a month to monitor their international normalized ratio (INR). The INR is an indicator of how long it takes for your blood to clot and whether you’re within a safe therapeutic range (typically between 2 and 3).
Responses to NOACs are often more predictable than responses to warfarin, notes Knight. And there aren’t as many drug or food interactions. For example, patients on warfarin must stick to a restricted diet because warfarin interacts with vitamin K, which is found in leafy greens and other foods.
“But warfarin has been around for a long time and is less expensive than NOACs,” says Knight. “So if a patient has been on warfarin for several years and is doing well, a doctor may still recommend the newer drugs, but leave the option up to the patient. Especially if the patient has honed ways to check their INR or if cost is a concern.”
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Switching From Warfarin to NOACs When Appropriate
For people who are eligible to transition from warfarin to NOACs, the process is fairly straightforward and is already being done in clinical practice. “The way that you do it is to monitor the INR,” says January, noting that warfarin affects the way that blood coagulates and many things can affect it. “If we stop warfarin, when the INR drops below 2, we can start the NOAC.”
However, there are two types of patients for whom warfarin is still the best option:
- Patients who have moderate to severe mitral valve stenosis — a narrowing of the mitral valve opening, restricting blood flow from the left atrium to the left ventricle — should remain on warfarin as they were excluded from the original NOAC clinical trials.
- Patients who have mechanical heart valves
“These are the two exceptions when we say we prefer NOACs over warfarin,” says January.
Other Options for Managing Afib if You Can’t Take Blood Thinners
Catheter ablation, a procedure that creates small scars in your heart tissue to stop abnormal electrical signals from moving through your heart, may be an option for patients with recurrent, symptomatic afib who have failed medical therapy, notes Knight. But there is little evidence that an ablation, even if it’s effective, lowers your risk of stroke. The goal of ablation is to improve quality of life, not to reduce stroke risk.
“Keeping your weight down is also very important whether you’re newly diagnosed with your first episode of afib and you’re trying to reduce a recurrence — or if you’ve had afib for many years,” says Knight.
Lastly, if you can’t take blood thinners or have difficulty tolerating them, other nonpharmacological options, like left atrial appendage occlusion, may be appropriate. Talk to your doctor about which afib treatments are best for your situation.