Atrial fibrillation (AFib) is a heart rhythm disorder in which the heart beats irregularly. It affects more than 2 million Americans, many of whom have no idea they have it.
Atrial fibrillation can be managed in a number of different ways, but almost everyone who is diagnosed with it ends up taking at least one type of medication.
There are three main types of medication used in treating AFib: blood thinners, rate control drugs, and anti-arrhythmic drugs.
If you have AFib, you have a five times greater risk of suffering a stroke than someone without AFib. That’s by far the most significant issue with this condition. "If you’re weak and tired or short of breath, that’s bad, but a stroke is catastrophic," says John Wylie, MD, director of electrophysiology services for Massachusetts-based Caritas Christi Health Care.
For that reason, the first thing your doctor will do after you’ve been diagnosed with AFib is talk to you about medications to prevent stroke. Your stroke risk can be put into perspective, using a formula known as CHADS2 or CHADS2-VASc.
It stands for:
- C-Congestive heart failure
- H-High blood pressure
- A-Age 75 or older
- S2-Previous stroke
Having any of the conditions earns you one point; a previous stroke gets you two. The VASc part of the scoring system is newer, and evidence shows that it’s more precise. It adds points for being a woman (women with AFib are at greater stroke risk), peripheral vascular disease, and being older than 65.
"If a person is young and has no other stroke risk factors, such as high blood pressure or diabetes, sometimes we will just treat them with aspirin, because their risk of stroke is still relatively low," says William Whang, MD, assistant professor of clinical medicine in the division of cardiology at Columbia University Medical Center.
But it doesn’t take much to bump you up the medication scale. If you score higher than a 1 on CHADS2-VASc, your doctor may advise you to seriously consider more powerful stroke prevention in the form of blood thinning medications.
Common blood thinners used in AFib patients are:
- Coumadin (warfarin)
- Pradaxa (dabigatran)
- Xarelto (rivaroxaban)
All of these are pills you take every day. They target factors that your blood needs to form clots, but they work a little differently. Pradaxa and Xarelto work directly on thrombin, the blood’s central clotting agent, while Coumadin competes with vitamin K, which your liver needs to create the proteins that help blood to clot.
Because they inhibit the blood’s ability to clot, these drugs also carry the risk of bleeding. But since Coumadin’s effects are more variable based on a person’s size, weight, gender, and other medications being used, patients taking Coumadin have to get regular blood tests (usually at least monthly) to make sure they don’t have too much or too little of the drug in their system. Pradaxa and Xarelto, on the other hand, are more predictable and don't require the same frequent blood testing.