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How Is Atrial Fibrillation Diagnosed?

Some people who have atrial fibrillation (Atrial Fibrillation) don't have symptoms. For these people, Atrial Fibrillation often is found during a physical exam or EKG (electrocardiogram) test done for another purpose. Other times, Atrial Fibrillation is diagnosed after a person goes to the doctor because of symptoms.

To understand why a person has Atrial Fibrillation and the best way to treat it, the doctor will want to find any immediate or underlying causes of the condition.

Doctors use several methods to diagnose Atrial Fibrillation, including taking medical and family histories, doing a physical exam, and doing several tests and procedures.

Specialists Involved

A primary care doctor often is involved in the initial diagnosis and treatment of Atrial Fibrillation. These doctors can include family practitioners and internists.

Doctors who specialize in the diagnosis and treatment of heart disease also may be involved, such as:

  • Cardiologists. These are doctors who diagnose and treat heart diseases and conditions.
  • Electrophysiologists. These are cardiologists who specialize in arrhythmias.

Medical and Family Histories

Your doctor will ask questions about your:

  • Signs and symptoms. What symptoms are you having? Have you had palpitations? Are you dizzy or short of breath? Are your feet or ankles swollen (a possible sign of heart failure)? Do you have any chest pain?
  • Medical history. This includes other health problems, such as a history of heart disease, high blood pressure, lung disease, diabetes, or thyroid problems.
  • Family's medical history. Does anyone in your family have a history of Atrial Fibrillation? Has anyone in your family ever had heart disease or high blood pressure? Has anyone had thyroid problems? Are there other illnesses or health problems in your family?
  • Health habits. Your doctor may ask whether you smoke or use alcohol or caffeine.

Physical Exam

Your doctor will do a complete cardiac exam, listening to the rate and rhythm of your heartbeat and taking your pulse and blood pressure reading. He or she will likely check to see whether you have any signs of heart muscle or valve problems. Your doctor will listen to your lungs to check for signs of heart failure.

Your doctor also will check for swelling in your legs or feet and look for an enlarged thyroid gland or other signs of hyperthyroidism (too much thyroid hormone).

Diagnostic Tests and Procedures


An EKG is a simple, painless test that records the heart's electrical activity. It's the most useful test for diagnosing Atrial Fibrillation.

An EKG shows how fast your heart is beating and its rhythm (steady or irregular). It also records the strength and timing of electrical signals as they pass through each part of your heart.

A standard EKG only records the heartbeat for a few seconds. It won't detect an Atrial Fibrillation episode that doesn't happen during the test. To diagnose paroxysmal Atrial Fibrillation, your doctor may ask you to wear a portable EKG monitor that can record your heartbeat for longer periods.

The two most common types of portable EKGs are Holter and event monitors.

Holter and Event Monitors

 A Holter monitor records the heart's electrical activity for a full 24- or 48-hour period. You wear small patches called electrodes on your chest. These patches are connected by wires to a small, portable recorder. The recorder can be clipped to a belt, kept in a pocket, or hung around your neck.

You wear the Holter monitor while you do your normal daily activities. This allows the monitor to record your heart for a longer time than a standard EKG.

An event monitor is similar to a Holter monitor. You wear an event monitor while doing your normal activities. However, an event monitor only records your heart's electrical activity at certain times while you're wearing it.

For many event monitors, you push a button to start the monitor when you feel symptoms. Other event monitors start automatically when they sense abnormal heart rhythms.

You might wear an event monitor for 1 to 2 months, or as long as it takes to get a recording of your heart during symptoms.

Stress Test

Some heart problems are easier to diagnose when your heart is working hard and beating fast. During stress testing, you exercise (or are given medicine if you're unable to exercise) to make your heart work hard and beat fast while heart tests are done.


Echocardiography (echo) uses sound waves to create a moving picture of your heart. The test provides information about the size and shape of your heart and how well your heart chambers and valves are working.

Echo also can identify areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.

This test is sometimes called transthoracic echocardiography. It's painless and noninvasive (no instruments are inserted into the body). The test is done by placing a device called a transducer on your chest. The device sends special sound waves through your chest wall to your heart.

The sound waves bounce off the structures of your heart, and a computer converts them into pictures on a screen.

Trans esophageal Echocardiography

Transesophageal echo, or TEE, takes pictures of your heart through the esophagus (the passage leading from your mouth to your stomach).

The atria are deep in your chest and often can't be seen very well using transthoracic echo. Your doctor can see the atria much better using TEE.

During this test, the transducer is attached to the end of a flexible tube that's guided down your throat and into your esophagus. You'll probably be given medicine to help you relax during the procedure. TEE is used to detect blood clots that may be developing in the atria because of Atrial Fibrillation.

Chest X Ray

A chest x ray is a painless test that creates pictures of the structures in your chest, such as your heart and lungs. This test can show fluid buildup in the lungs and other complications of Atrial Fibrillation.

Blood Tests

Blood tests check the level of thyroid hormone and the balance of your body's electrolytes. Electrolytes are minerals that help maintain fluid levels and acid-base balance in the body. They're essential for normal health and functioning of your body's cells and organs.

How Is Atrial Fibrillation Treated?

Treatment for atrial fibrillation (Atrial Fibrillation) depends on how severe or frequent the symptoms are and whether you already have heart disease. General treatment options include medicines, medical procedures, and lifestyle changes.

Goals of Treatment

The goals of treating Atrial Fibrillation include:

  • Preventing blood clots from forming, thereby reducing the risk of stroke.
  • Controlling how many times a minute the ventricles contract. This is called rate control. Rate control is important because it allows the ventricles enough time to completely fill with blood. With this approach, the irregular heart rhythm continues, but the person feels better and has fewer symptoms.
  • Restoring a normal heart rhythm. This is called rhythm control. Rhythm control allows the atria and ventricles to work together to efficiently pump blood to the body.
  • Treating any underlying disorder that's causing or raising the risk of Atrial Fibrillation—for example, hyperthyroidism (too much thyroid hormone).

Who Needs Treatment for Atrial Fibrillation?

People who have Atrial Fibrillation but don't have symptoms or related heart problems may not need treatment. Atrial Fibrillation may even go back to a normal heart rhythm on its own. (This also can occur in people who have Atrial Fibrillation with symptoms.)

In some people who have Atrial Fibrillation for the first time, doctors may choose to use an electrical procedure or medicine to restore the heart rhythm to normal.

Repeated episodes of Atrial Fibrillation tend to cause changes to the heart's electrical system, leading to persistent or permanent Atrial Fibrillation. Most people who have persistent or permanent Atrial Fibrillation need treatment to control their heart rates and prevent complications.

Specific Types of Treatment

Blood Clot Prevention

The risk of a blood clot traveling from the heart to the brain and causing a stroke is increased in people who have Atrial Fibrillation. Preventing blood clots from forming is probably the most important part of treating Atrial Fibrillation.

Doctors prescribe blood-thinning medicines to prevent blood clots. These medicines include warfarin (Coumadin®), heparin, and aspirin.

Warfarin is the most effective medicine in people who have risk factors for stroke. People taking warfarin must have regular blood tests to check how well the medicine is working.

Rate Control

Doctors prescribe medicines to slow down the rate at which the ventricles are beating. These medicines help bring the heart rate to a normal level.

Rate control is the recommended treatment for most patients who have Atrial Fibrillation, even though an abnormal heart rhythm continues and the heart doesn't work as well as it should. Most people feel better and can function well if their heart rates are well-controlled.

Medicines used to control the heart rate include beta blockers (for example, metoprolol and atenolol), calcium channel blockers (diltiazem and verapamil), and digitalis (digoxin). Several other medicines also are available.

Rhythm Control

Doctors use medicines or procedures to restore and maintain the heart's rhythm. This treatment approach is recommended for people who aren't functioning well with rate control treatment or who have only recently started having Atrial Fibrillation.

The longer you have Atrial Fibrillation, the less likely it is that an abnormal heart rhythm can be restored to a normal heart rhythm. This is especially true for people who have had Atrial Fibrillation for 6 months or more.

Restoring a normal rhythm also becomes less likely if the atria become enlarged or if any underlying heart disease becomes more severe. In these cases, the chance that Atrial Fibrillation will recur is high, even if you're taking medicine to help convert Atrial Fibrillation to a normal rhythm.

Medicines. Medicines used to control the heart rhythm include amiodarone, sotalol, flecainide, propafenone, dofetilide, and ibutilide. Occasionally, older medicines, such as quinidine, procainamide, and disopyramide, are used.

Your doctor will carefully tailor the dose and type of medicines he or she prescribes to treat your Atrial Fibrillation. This is because medicines used to treat Atrial Fibrillation can cause a different kind of arrhythmia. They also can harm people who have underlying diseases of the heart or other organs. This is particularly true for patients who have an unusual heart rhythm problem called Wolff-Parkinson-White syndrome.

Your doctor may start you on a small dose of medicine and then gradually increase the dose until your symptoms are controlled. Medicines used for rhythm control can be given regularly by injection at a doctor's office, clinic, or hospital. Or, you may routinely take pills to try to control Atrial Fibrillation or prevent recurrences.

If your doctor knows how you'll react to a medicine, a specific dose may be prescribed for you to take on an as-needed basis if you have an episode of Atrial Fibrillation.

Procedures. Doctors use several procedures to restore a normal heart rhythm. Electrical cardioversion is a procedure used to restore a fast or irregular heartbeat to a normal rhythm. For the procedure, low-energy shocks are given to your heart to trigger a normal rhythm. You're temporarily put to sleep before the shocks are given.

Electrical cardioversion isn't the same as the emergency heart shocking procedure often seen on TV programs. It's planned in advance and done under carefully controlled conditions.

Before doing electrical cardioversion, your doctor may recommend transesophageal echocardiography (TEE) to rule out the presence of blood clots in the atria. If clots are present, you may need to take blood-thinning medicines for a period of time to help get rid of the clots before the procedure.

Catheter ablation may be used to restore a normal heart rhythm when medicines or electrical cardioversion don't work. During this procedure, a wire is inserted through a vein in the leg or arm and threaded to the heart.

Radio wave energy is sent through the wire to destroy abnormal tissue that may be disrupting the normal flow of electrical signals. An electrophysiologist usually does this procedure in a hospital.

Sometimes catheter ablation is used to destroy the atrioventricular (AV) node. The AV node is where the heart's electrical signals pass from the atria to the ventricles. This procedure requires your doctor to surgically implant a device called a pacemaker to maintain a normal heart rhythm.

Research to examine the benefits of catheter ablation as a treatment for Atrial Fibrillation is still ongoing.

Another procedure to restore a normal heart rhythm is called "maze" surgery. During this procedure, the surgeon makes small cuts or burns in the atria that prevent the spread of disorganized electrical signals.

This procedure requires open-heart surgery, so it's usually done when a person requires heart surgery for other reasons, such as for valve disease (which can increase the risk of Atrial Fibrillation).

Approaches To Treating Underlying Causes and Reducing Risk Factors

Your doctor also may recommend other treatments for an underlying condition that may be causing Atrial Fibrillation or to reduce Atrial Fibrillation risk factors. For example, he or she may prescribe medicines to treat an overactive thyroid or reduce blood pressure.

Your doctor also may recommend lifestyle changes, such as following a healthy diet, cutting back salt intake (to help lower blood pressure), quitting smoking, and reducing stress.

Limiting or avoiding stress and alcohol, caffeine, or other stimulants that may increase your heart rate also may help reduce the risk of Atrial Fibrillation.

How Can Atrial Fibrillation Be Prevented?

You may be able to prevent atrial fibrillation (Atrial Fibrillation) by following a healthy lifestyle and taking steps to lower your risk of heart disease. These steps include:

  • Following a heart healthy diet that's low in saturated fat, trans fat, and cholesterol. A healthy diet includes a variety of whole grains, fruits, and vegetables daily.
  • Not smoking.
  • Getting physical activity regularly.
  • Maintaining a healthy weight.

If you have heart disease or other Atrial Fibrillation risk factors, work with your doctor to control your condition and lower your risk of complications, such as Atrial Fibrillation.

In addition to following the healthy lifestyle steps above, which also can help control heart disease, your doctor may advise you to take one or more of the following steps:

  • Follow the DASH eating plan to help lower your blood pressure.
  • Keep your cholesterol and triglycerides at healthy levels with dietary changes and/or medicines.
  • Limit or avoid alcohol.
  • Control your blood glucose (blood sugar) levels if you have diabetes.
  • Get ongoing medical care and take your medicines as prescribed.

For more information about following a healthy lifestyle, visit the National Heart, Lung, and Blood Institute's Aim for a Healthy Weight Web site, "Your Guide to a Healthy Heart," "Your Guide to Lowering Your Blood Pressure With DASH," and "Your Guide to Physical Activity and Your Heart."

Living With Atrial Fibrillation

People who have atrial fibrillation (Atrial Fibrillation)—even permanent Atrial Fibrillation—can live normal, active lives. If you have Atrial Fibrillation, ongoing medical care is important.

Keep all your medical appointments. Bring all the medicines you're taking to every doctor and emergency room visit. This will help your doctor know exactly what medicines you're taking.

Follow your doctor's instructions for taking medicines. Be careful about taking over-the-counter medicines, nutritional supplements, and cold and allergy medicines. Some of these products contain stimulants that can trigger rapid heart rhythms. Some over-the-counter medicines can have harmful interactions with heart rhythm medicines.

Tell your doctor if your medicines are causing side effects, if your symptoms are getting worse, or if you have new symptoms.

If you're taking blood-thinning medicines, you'll need to be carefully monitored. For example, you may need regular blood tests to check how the medicines are working.

Talk with your doctor about diet, physical activity, weight control, and alcohol use. Find out what steps you can take to manage your condition.