Atrial Fibrillation

If you have atrial fibrillation, the upper left chamber of your heart beats rapidly and unpredictably, making it hard for all the blood in the chamber to empty. The remaining blood tends to form clots that can travel to any part of your body. If they travel to the brain, these clots can cause a stroke. Treatment with anticoagulants (or blood-thinners) such as warfarin can prevent these clots from forming. Aspirin also is used to reduce the risk of stroke, but the most recent clinical studies have shown that warfarin is superior to aspirin in preventing stroke. Current studies show that treatment with warfarin can prevent over half of the 80,000 strokes that are caused annually by atrial fibrillation.

If you have atrial fibrillation, your health care provider may recommend that you take warfarin. If you do, you need to know:

• Warfarin may increase the risk of bleeding. Careful regular monitoring of blood levels and proper dosage should keep this risk in check. Your health care provider will tell you where to go for monitoring.
• When properly administered, warfarin prevents 20 strokes for every major bleeding complication caused by the medicine.
• Most bleeding incidents are preventable and treatable.
• Certain drugs can interfere with proper anticoagulation. Antibiotics and anticonvulsants (for example, phenobarbital and Tegretol) are examples of drugs that can cause problems. Talk to your physician or pharmacist for more complete information.