Harvard Heart Letter

Ask the doctor: Do I need to take warfarin for occasional lone atrial fibrillation?

Q. I'm 64 and have had lone atrial fibrillation for about a decade. I have an echocardiogram every year to make sure the rest of my heart is okay. (It is.) My doctor hasn't prescribed any medications for me, but she wants me to take a blood thinner when I hit my 65th birthday. I'd rather not do this. Should I follow her recommendation? Also, is it possible that the endurance-type exercise regimens I have performed over many years led to my developing lone atrial fibrillation?

A. The decision to start taking warfarin (generic, Coumadin, Jantoven) for lone atrial fibrillation (atrial fibrillation not caused by underlying heart disease) or any other type of this heart rhythm disorder depends on several factors, not just age. Most cardiologists use the CHADS2 score (it stands for Cardiac failure, Hypertension, Age, Diabetes, and Stroke [doubled]) to help make the decision. As you can see in the table, age does not accrue any points until 75 years and older. If your CHADS2 score is zero, and you truly have lone atrial fibrillation, then it should be fine to hold off on taking warfarin. Some doctors recommend anticoagulation for people who are often or always in atrial fibrillation even though they have a CHADS2 score of zero, but this approach is not part of current guidelines for treating atrial fibrillation.

CHADS2 score

Risk factor

Points

Heart failure

1

High blood pressure

1

Age 75 or older

1

Diabetes

1

Prior stroke or transient ischemic attack or blood clot

2

Scoring: Circle any risk factor that applies to you and add up the circled points. 0: Anticoagulation with warfarin generally isn't needed. 1: Take aspirin or warfarin (although warfarin is preferred). 2 or higher: Take warfarin.

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