Atrial Fibrillation

Your Heart is a Pump
Your heart is made up of four chambers. The two upper chambers are called atria. The atria collect the blood that comes into the heart. They contract (squeeze) to pump blood to the lower chambers, called ventricles. The ventricles contract to pump the blood out of the heart. This pumping creates your heartbeat. The heart normally beats at between 60 and 100 bpm.

Your Heart's Electrical System
To pump, the heart needs an electrical system. This system contains electrical cells. These cells create and move signals that tell the heart when to beat. Some of these cells form groups called nodes. Others form pathways that carry signals through the heart.

Atrial Flutter
With atrial flutter, signals travel around and around inside the atria. Circling signals tell the atria to beat quickly (around 200 to 300 bpm). Atrial flutter can cause symptoms similar to atrial fibrillation. It can also lead to the even faster, uneven rhythms of atrial fibrillation.

Atrial Fibrillation
With atrial fibrillation, cells in the atria send extra signals make the atria beat very quickly (from 400 to 500 bpm) and unevenly. (The ventricles may beat as fast as 180 bpm.) The atria beat so fast and unevenly that they may quiver instead of contracting. If the atria don't contract, they don't move enough blood into the ventricles. This is what leads to symptoms such as dizziness and weakness. Blood that isn't kept moving can pool and form clots in the atria. These clots can move into other parts of the body and cause serious problems, such as a stroke.

Echocardiogram
An echocardiogram takes a video picture of your heart. Harmless sound waves bounce off the heart. These sound waves become a moving image on a video screen. Your doctor may order this test to check the structures of your heart.

Preventing Clots
If a blood clot forms in the atria, part of the clot can break off and travel from your heart to your brain. This can cause a stroke. You may be given an anticoagulant. This is a medication that helps keep blood clots from forming. Aspirin is sometimes used as an anticoagulant. Coumadin (warfarin) is a prescription anticoagulant. If you take Coumadin, a blood test will be done to be sure the dosage is not too high or low. The result of this test are given in a number called either protime or INR. Always know your current Coumadin dose, your protime/INR, and when your next blood test is due.

Risks of Coumadin
Coumadin can help protect you from a stroke. But taking it for a long time has some risks. These include:

• Excessive bleeding
• Birth defects (if taken by a pregnant woman)

Caution: Aspirin, antibiotics, certain foods, or other medications can affect how Coumadin works. Always ask your doctor before taking any medication, including one bought without a prescription. Alcohol can also affect Coumadin, so check with your doctor before you drink.

Electrical Cardioversion
Cardioversion is a way to restore your heart's normal rhythm. "Chemical" cardioversion is done with medications. If medications don't work, electrical cardioversion may be the next step. This procedure uses electricity to help your heartbeat become normal again.