Atrial Fibrillation

What is atrial fibrillation?

Atrial fibrillation is a change in your heart rhythm. It causes an irregular and sometimes very fast heartbeat.

How does it occur?

An electrical impulse in your heart starts each heartbeat. Normally, this impulse starts in the right upper chamber of the heart (the right atrium). It then moves along a pathway to the lower chambers of the heart (the ventricles).

In atrial fibrillation, the electrical signal in the upper part of your heart is chaotic. The atrial muscles quiver. The electrical impulses reach the lower chambers of the heart irregularly. The irregularity can make it harder for your heart to pump efficiently. The heart may also beat very fast.

Common causes of atrial fibrillation are:

• heart disease, including coronary artery disease, heart enlargement due to many years of high blood pressure, and heart failure from other causes including congenital heart disease
• problems with a heart valve, such as damage to the mitral valve (located between the upper and lower left heart chambers), usually by rheumatic fever or mitral valve prolapse

Other causes of atrial fibrillation include:

• an overactive thyroid gland
• pneumonia
• chronic lung disease
• heavy drinking of alcohol.

Sometimes no cause for atrial fibrillation can be found.

What are the symptoms?

The most common symptoms are:

• irregular heartbeat
• fast heart rate
• dizziness and lightheadedness
• heart palpitations that feel like a sudden pounding, fluttering, or racing in the chest
• weakness
• fatigue
• shortness of breath
• chest pain or a sense of pressure in the chest.

When atrial fibrillation affects the pumping of your heart, your blood pressure may fall. You may feel lightheaded and faint.

Occasionally, the first symptom is a stroke, caused by a blood clot that formed in the fibrillating atrium and traveled to the brain.

How is it diagnosed?

Your healthcare provider will ask about your symptoms and examine you. The diagnosis can be confirmed with an electrocardiogram (ECG). An ECG measures the electrical activity of your heart. It shows a special pattern when you are having atrial fibrillation. Sometimes atrial fibrillation comes and goes before it can be seen on an ECG. In this case, you may have to wear a Holter monitor or event recorder to record your heart rate. The Holter monitor is a portable ECG used to detect heart rhythm problems.

Your provider will use your medical history, physical exam, and blood tests to look for a treatable cause of the abnormal heartbeat. You may also have an echocardiogram. This test uses sound waves to make images of your heart. It is a way to check for problems with the structure of the heart, such as an abnormal mitral valve.

How is it treated?

Treatment depends on:

• the cause of the fibrillation
• the severity of your symptoms
• your medical history.

If a medical problem is causing atrial fibrillation, treatment of the underlying problem usually causes the rhythm to go back to normal.

If your symptoms are not severe, treatment is usually a medicine to keep your heart from beating too fast. Medicines that can keep the heart from beating too fast are beta blockers, digoxin, and the calcium channel blockers diltiazem and verapamil.

Atrial fibrillation can cause blood clots in the heart. The blood clot could move to the neck or brain and block blood flow to the brain, causing a stroke. If your medical history puts you at high risk for forming a blood clot, you may need to take blood thinners, such as warfarin (Coumadin), to prevent a stroke.

If your symptoms are more severe, you may need to have your heart put back to a normal rhythm. You may be treated with anti-arrhythmic medicines or cardioversion. For cardioversion an anesthetic is given to keep you from feeling pain and then an electrical shock is applied to your chest that causes your heart to begin beating normally again.

If medicines don't work, your provider might suggest a procedure called cardiac ablation to treat atrial fibrillation or to keep you from having it again. This procedure delivers radio waves to the inside of the heart. It blocks abnormal electrical pathways in the heart and helps stop abnormal heart rhythms.

How long will the effects last?

For some people atrial fibrillation lasts just a short time and the heart goes back to a normal rhythm on its own. If you keep having spells of atrial fibrillation, medicines to control heart rate may help prevent you from having more spells, or you may have them less often. In some cases you may stay in atrial fibrillation permanently but if your heart rate is controlled, often the atrial fibrillation is well tolerated and you can do many of the activities you may have done when you did not have atrial fibrillation.

The most serious complication of atrial fibrillation is a stroke caused by a blood clot in the brain. During atrial fibrillation, blood clots can form in the heart. Clots may then travel in the bloodstream to the brain, where they can block blood flow to a part of the brain and cause a stroke. The risk of a stroke can be reduced by blood thinners.

How can I take care of myself?

• Take your medicines as prescribed.
• If you take anticoagulants, keep appointments for follow-up blood tests. Make sure your healthcare provider knows about changes in your diet or medical condition and about any other medicines, including nonprescription medicines, or supplements you are taking.
• Although an occasional alcoholic or caffeinated drink is usually OK, you may find that larger amounts of alcohol or caffeine trigger symptoms, and you may need to reduce or avoid alcohol or caffeine in your diet.
• Contact your healthcare provider right away if you have any new symptoms or symptoms that come back, such as falling or fainting.

How can I help prevent atrial fibrillation?

The best prevention is to have a heart-healthy lifestyle. Eat a healthy diet, stay fit with the right kind of exercise for you, do not smoke, and limit your use of alcohol. If you have heart disease or high blood pressure, follow your healthcare provider's advice closely.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File card3606.htm Release 13/2010