Atrial fibrillation (AFib) is a type of heart rhythm disorder that affects the two upper chambers of the heart (the atria). In AFib, the heart beats irregularly and rapidly, causing blood to pool in the atria and increasing the risk of blood clots.

AFib is a common condition, and risk factors include increasing age, high blood pressure, heart disease, obesity, and a family history of AFib.

The symptoms of AFib can vary, but may include:

• Palpitations (a racing or fluttering heartbeat)
• Fatigue
• Shortness of breath
• Chest pain or pressure
• Lightheadedness or dizziness
• Fainting

Diagnosis of AFib typically involves a physical exam, electrocardiogram (ECG), and sometimes additional tests such as an echocardiogram or blood tests.

Treatment for AFib may involve medications to control heart rate and rhythm, blood thinners to reduce the risk of blood clots, and procedures to restore a normal heart rhythm (such as cardioversion or ablation). In some cases, a pacemaker may be necessary to regulate heart rate.

Living with AFib can present challenges, but with proper care and management, many people are able to maintain good heart health and enjoy an active and fulfilling life. If you are experiencing symptoms of AFib, it's important to see a doctor for a proper evaluation and to discuss the best course of treatment.

To understand the causes of A-fib, it may be helpful to know how the heart typically beats.

The typical heart has four chambers — two upper chambers (atria) and two lower chambers (ventricles). Within the upper right chamber of the heart (right atrium) is a group of cells called the sinus node. The sinus node is the heart's natural pacemaker. It produces the signal that starts each heartbeat.

In a regular heart rhythm:

The signal travels from the sinus node through the two upper heart chambers (atria).

The signal passes through a pathway between the upper and lower chambers called the atrioventricular (AV) node.

The movement of the signal causes your heart to squeeze (contract), sending blood to your heart and body.

In atrial fibrillation, the signals in the upper chambers of the heart are chaotic. As a result, the upper chambers shake (quiver). The AV node is then bombarded with signals trying to get through to the lower heart chambers (ventricles). This causes a fast and irregular heart rhythm.

The heart rate in atrial fibrillation may range from 100 to 175 beats a minute. The normal range for a heart rate is 60 to 100 beats a minute.

Causes of atrial fibrillation

Problems with the heart's structure are the most common cause of atrial fibrillation. Possible causes of atrial fibrillation include:

Coronary artery disease

Heart attack

Heart defect that you're born with (congenital heart defect)

Heart valve problems

High blood pressure

Lung diseases

Physical stress due to surgery, pneumonia or other illnesses

Previous heart surgery

Problem with the heart's natural pacemaker (sick sinus syndrome)

Sleep apnea

Thyroid disease such as an overactive thyroid (hyperthyroidism) and other metabolic imbalances

Use of stimulants, including certain medications, caffeine, tobacco and alcohol

Viral infections

Some people who have atrial fibrillation have no known heart problems or heart damage.

Healthy lifestyle choices can reduce the risk of heart disease and may prevent atrial fibrillation. Here are some basic heart-healthy tips:

Eat a nutritious diet

Get regular exercise and maintain a healthy weight

Don't smoke

Avoid or limit alcohol and caffeine

Manage stress, as intense stress and anger can cause heart rhythm problems

Treatment for atrial fibrillation depends on how long you've had A-fib, your symptoms and the underlying cause of the heartbeat problem. The goals of treatment are to:

Reset the heart rhythm

Control the heart rate

Prevent blood clots that can lead to stroke

Atrial fibrillation treatment may involve:

Medications

Therapy to reset the heart rhythm (cardioversion)

Surgery or catheter procedures

Together, you and your doctors will discuss the best treatment option for you. It's important to follow your atrial fibrillation treatment plan. If A-fib isn't well controlled, it may lead to other complications, including strokes and heart failure.

Medications

You may be prescribed medications to control how fast your heart beats and restore it to a normal rate. Medications are also prescribed to prevent blood clots, a dangerous complication of A-fib.

Medications used to treat atrial fibrillation include:

Beta blockers. These medications can help slow the heart rate at rest and during activity.

Calcium channel blockers. These medicines control the heart rate but may need to be avoided by those who have heart failure or low blood pressure.

Digoxin. This medication may control the heart rate at rest, but not as well during activity. Most people need additional or alternative medications, such as calcium channel blockers or beta blockers.

Anti-arrhythmic medications. These drugs are used to maintain a normal heart rhythm, not just to control the heart rate. Because they tend to have more side effects than drugs that control the heart rate, anti-arrhythmics tend to be used more sparingly.

Blood thinners. To reduce the risk of stroke or damage to other organs caused by blood clots, a doctor may prescribe a blood-thinning medication (anticoagulant). Blood thinners include warfarin (Jantoven), apixaban (Eliquis), dabigatran (Pradaxa), edoxaban (Savaysa) and rivaroxaban (Xarelto). If you take warfarin, you'll need to have regular blood tests to monitor the drug's effects.

Cardioversion therapy

If A-fib symptoms are bothersome or if this is the first episode of atrial fibrillation, a doctor may attempt to reset the heart rhythm (sinus rhythm) using a procedure called cardioversion.

Cardioversion can be done in two ways:

Electrical cardioversion. This method to reset the heart rhythm is done by sending electric shocks to the heart through paddles or patches (electrodes) placed on the chest.

Drug cardioversion. Medications given through an IV or by mouth are used to reset the heart rhythm.

Cardioversion is usually done in a hospital as a scheduled procedure, but it may be done in emergency situations. If it's scheduled, warfarin (Jantoven) or another blood thinner may be given a few weeks before it's done to reduce the risk of blood clots and strokes.

After electrical cardioversion, anti-arrhythmic medications may be prescribed indefinitely to help prevent future episodes of atrial fibrillation. Even with medications, there is a chance of another episode of atrial fibrillation.

Surgery or catheter procedures

A heart during AV node ablation

AV node ablationOpen pop-up dialog box

If A-fib doesn't get better with medications or other therapies, a doctor might recommend a procedure called cardiac ablation. Sometimes ablation is the first treatment for certain patients.

Cardiac ablation uses heat (radiofrequency energy) or extreme cold (cryoablation) to create scars in your heart to block abnormal electrical signals and restore a normal heartbeat. A doctor inserts a flexible tube (catheter) through a blood vessel, usually in your groin, and into your heart. More than one catheter may be used. Sensors on the tip of the catheter apply the cold or heat energy.

Less commonly, ablation is performed using a scalpel during open-heart surgery.

There are different types of cardiac ablation. The type used to treat atrial fibrillation depends on your specific symptoms, overall health and whether you're having another heart surgery.

For example, some of the types of cardiac ablation that may be used to treat atrial fibrillation are:

Atrioventricular (AV) node ablation. Heat or cold energy is applied to the heart tissue at the AV node to destroy the electrical signaling connection. After AV node ablation, a pacemaker is needed for life.

Maze procedure. A doctor uses heat or cold energy or a scalpel to create a pattern of scar tissue (the maze) in the upper chambers of the heart. Because scar tissue doesn't send electrical signals, the maze interferes with the stray heart signals that cause atrial fibrillation.

If a scalpel is used to create the maze pattern, open-heart surgery is necessary. This is called the surgical maze procedure. It's the preferred method of atrial fibrillation treatment in those who need another heart surgery, such as coronary artery bypass surgery or heart valve repair.

Atrial fibrillation may return after cardiac ablation. If this happens, another cardiac ablation or other heart treatment may be recommended.