What is atrial fibrillation?

Atrial fibrillation is the most common heart rhythm problem seen today.

With a normal heart rhythm, the heartbeat begins with an electrical impulse in an upper chamber of the heart. This upper chamber (right atrium) sets a regular, even pace. The impulses are sent across to the other upper chamber and down to the bottom chambers of the heart (ventricles). The ventricles then pump each heartbeat in regular, even beats.

With atrial fibrillation, the upper chamber of the heart no longer beats in a regular, even pace. Instead, the electrical impulses move about both upper chambers (atria) in a chaotic, or quiver-like pattern. When the messages from these irregular impulses are delivered to the bottom chambers of the heart (ventricles), the ventricles then pump with an irregular, uneven pace (irregular heartbeat).

What are the signs and symptoms of atrial fibrillation?

Sometimes, people who have atrial fibrillation have no symptoms. Other times, they may have strange heartbeat sensations, fatigue, lightheadedness, or severe symptoms such as loss of consciousness (because their heart is beating either too fast or too slow).

Are there any risks with having atrial fibrillation?

A major risk of atrial fibrillation is stroke. The risk factors which appear to make the risk of stroke higher in individuals with atrial fibrillation include:

• being older than 65 years
• having diabetes
• having high blood pressure
• having congestive heart failure
• having mitral stenosis (tight mitral valve)
• having history of a stroke or near-stroke (Transient Ischemic Attack)

What causes atrial fibrillation?

Other health problems that can cause atrial fibrillation include:

• high blood pressure
• heart artery disease
• heart valve disease
• thyroid problems

How is atrial fibrillation treated?

Often when other related health problems are treated, the atrial fibrillation goes away. Otherwise, the patient may need further treatment.

One type of treatment is called cardioversion. With a cardioversion, the patient's heart beat is slowed or stopped temporarily so the heart can begin beating more normally again. There are two basic types of cardioversion:

• Chemical cardioversion: The patient is given an antiarrhythmic medication (a medication that helps treat heart rhythm problems). This medication can sometimes help the heart switch back into a more normal rhythm on its own.
• Electrical cardioversion: While in the hospital, the patient is placed under general anesthesia for two to three minutes while an electrical shock is delivered to the heart. This electrical shock stops the heartbeat temporarily so that the heart can begin beating more normally again.

When someone's heart rhythm is in atrial fibrillation, the main concerns are to prevent a stroke and to be sure their heart rate isn't too fast or too slow. Stroke can be prevented by giving patients anti-clotting medication such as Coumadin (Warfarin). The rate of the patient's heartbeat can be treated with medication, a pacemaker, and/or with catheter ablation. When medications aren't working to keep a normal heart rate, a common treatment is to do a catheter ablation. With some types of catheter ablation, placement of a pacemaker is required.

• Catheter ablation: Atrial fibrillation is thought to be caused when cells in the top chambers of the heart send out rapid signals that override the normal heart beat. With catheter ablation, thin, flexible wires are inserted into a vein in the groin and threaded into the heart. Through an electrode at the tip of the wires, radio waves can be delivered to selectively destroy the very small area of heart tissue that may be responsible for the abnormal heart rhythm.
• Pacemaker placement: A pacemaker is a small electrical device surgically placed in the upper chest to monitor every heartbeat. When necessary, the pacemaker sends tiny electrical signals to stimulate the heart when the heartbeat becomes too slow.

6/16/2008