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What is atrial fibrillation?
What are the signs of atrial fibrillation?
What causes atrial fibrillation?
How does my doctor tell if I have atrial fibrillation?
How is atrial fibrillation treated?
What is atrial fibrillation?
Atrial fibrillation is a heart arrhythmia. It happens when your heart's two small upper chambers (the atria) quiver and beat rapidly instead of beating normally. This means that blood isn't pumped completely out of these chambers. This pooled blood can clot and later travel "downstream" to cause a stroke, which happens when a blood clot blocks an artery in the brain. About 15 percent of strokes occur in people with atrial fibrillation.
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What are the signs of atrial fibrillation?
Patients with atrial fibrillation may have these symptoms:
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A racing, pounding, or fluttering heartbeat |
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A "flopping" in the chest (heart palpitations) |
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Dizziness or light-headedness |
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Chest pain or pressure |
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Shortness of breath |
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Feeling weak or fatigued |
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Fainting (syncope) |
Symptoms may begin and stop suddenly.
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What causes atrial fibrillation?
Normally, the four chambers of the heart (two atria and two ventricles) beat in a very specific, coordinated manner. This beating is guided by an electrical impulse from the sinoatrial node, the body's natural pacemaker.
Atrial fibrillation occurs when electrical activity within the atrial chambers becomes chaotic and the sinoatrial node is no longer in charge.
The likelihood of developing atrial fibrillation increases with age. Other things that can make you more likely to have atrial fibrillation include:
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Coronary heart disease |
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Heart attack or heart failure |
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Heart valve disease |
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An inflamed heart muscle or lining (endocarditis) |
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Recent heart surgery |
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Arteriosclerosis, or narrowing of the arteries that carry blood to and from the heart |
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Angina, caused by the heart not getting enough oxygen |
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Congenital heart defects |
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Lung problems like chronic lung disease, pulmonary blood clots, emphysema, and asthma |
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Conditions like thyroid disorders, diabetes, and high blood pressure |
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Excessive alcohol consumption |
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Cigarette or stimulant drug use (including caffeine) |
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How does my doctor tell if I have atrial fibrillation?
Your doctor will first listen to your heart with a stethoscope to find an irregular rhythm. A normal heart beats 60 to 100 times a minute, but a heart with atrial fibrillation may beat 100 to 175 times a minute. Your doctor also may use some of the following tests:
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An electrocardiogram (ECG or EKG) measures the electrical activity of your heart. It helps your doctor see how well your heart beats, and can tell if your heart muscle has been damaged in any way. A technician puts small metal disks—electrodes—on your skin to read the pattern of electrical impulses from your heart. The test only takes a few minutes. |
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A Holter monitor provides a non-stop reading of your heart rate and rhythm as you go about your daily activities. You wear the small monitor at all times, and it makes a record of your heart's electrical activity, much like an electrocardiogram. This gives your doctor valuable information about what happens to your heart when you feel an irregular hearbeat. Holter monitors are most often used for a day or two. |
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Other tests: |
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An echocardiogram uses sound waves to make a picture of your heart. Your doctor sees this image on a television monitor, and can examine how well your heart works. The test takes about 45 minutes, and is painless. |
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Stress test: in this common test, a patient is first hooked up to monitoring equipment, which may include an electrocardiogram, and then told to walk slowly on a treadmill. A technician adjusts the speed and angle of the treadmill to make the patient's heart work harder. Afterwards, the technician may perform an echocardiogram. |
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In a heart catheterization, the doctor injects dye into the heart arteries and measures the blood flow and blood pressure in the heart chambers |
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An electrophysiology study (EPS) shows how your heart reacts to electrical signals. You will be awake, but under mild pain medicine, for the procedure. Your doctor first threads a thin, flexible tube—a catheter—from an artery in your leg up into your heart. He or she then uses small electrical impulses to make your heart beat at different speeds. This helps your doctor learn where the arrhythmia starts, and which medicines might help stop your heart's irregular rhythm. You will need to rest in the hospital for a few hours after an electrophysiology study. |
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How is atrial fibrillation treated?
Doctors have three goals in treating atrial fibrillation:
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Prevent blood clots from forming |
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Control your heart rate within a relatively normal range |
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Try to restore a normal heart rhythm |
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Medications |
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Many people who have atrial fibrillation are treated with a blood thinner (anticoagulant), such as warfarin. This prevents blood clots from forming, and reduces the chances of a stroke. |
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Calcium channel blockers slow the heart rate in atrial fibrillation |
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Beta-blockers decrease the heart rate and lower blood pressure by blocking the effects of adrenalin |
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Non-surgical procedures |
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Radiofrequency ablation uses a thin, flexible tube (catheter) to map the electrical impulses from your heart, and discover which cells are "misfiring." Doctors then use high-frequency radio waves to destroy the pathways causing the arrhythmia. With the patient awake and under local pain medicine, this procedure causes little discomfort. |
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Cryoablation is like radiofrequency ablation, except the surgeon uses a cold probe to destroy the problem cells |
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An electronic pacemaker acts like your heart's natural pacemaker and keeps your heart beating regularly. The device is implanted near the collarbone after the surgeon makes a small "pocket" under the skin. In most cases, the procedure takes about one hour. The patient is awake, and pain medication is given throughout. Most patients are able to return home one day later. |
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