What is atrial fibrillation?

Atrial fibrillation is an abnormal and irregular heartbeat, or heart rhythm. Caused by erratic electrical signals, atrial fibrillation occurs in the heart’s upper chambers, the atria. It causes the atria to beat so fast that they cannot contract fully, and properly circulate blood. The atria are not able to pump blood to the heart's lower chambers, the ventricles. These factors, in turn, cause other negative effects:

• Blood tends to pool in the atria, where it can clot and cause a stroke.
• The ventricles pump less oxygen-rich blood to the rest of the body, which can make a person feel tired.

What are the different stages of atrial fibrillation?

Atrial fibrillation is a progressive disease. If it is not treated, it progresses to a more advanced stage. The stages include the following.

Earliest Stage

• Paroxysmal atrial fibrillation: It starts and stops on its own or with treatment. It can stop within a day, but in order to be considered paroxysmal it must stop on its own within 7 days. (Paroxysmal means occasional.)

More Advanced Stages

• Persistent atrial fibrillation: It lasts beyond 7 days but not longer than 1 year.
• Long-standing persistent atrial fibrillation: It lasts, without stopping, for more than a year.

How common is atrial fibrillation?

Atrial fibrillation is the most common type of abnormal heartbeat, or heart rhythm. Today atrial fibrillation occurs in about 33 million people worldwide.¹ In the U.S, it is estimated to occur in about 8 million people. By 2030, about 12 million people in the U.S. will have it.²

Why are more people being diagnosed with atrial fibrillation?

Atrial fibrillation is more common in people age 60 and older. This makes it an increasing problem in the U.S. and in many other countries that have a large percentage of an aging population.

In addition, health experts in the U.S. say we currently have epidemics not just of obesity, but of heart disease and diabetes, too.^3-5 All of these health conditions put a person at higher risk of atrial fibrillation. Read more.

What are the most common symptoms of atrial fibrillation?

People with paroxysmal atrial fibrillation often have palpitations. This is a fluttering feeling in the chest, or a feeling of a rapid, irregular heartbeat.

People in a more advanced stage of atrial fibrillation are more likely to have these symptoms:

• Shortness of breath
• Dizziness
• Weakness
• Fatigue
• Lowered blood pressure
• Pain or pressure in the chest
• Rapid or irregular hearbeat

How is atrial fibrillation diagnosed?

Your health care provider will start out by getting information about your medical history. He or she will likely:

• Do a physical exam 
• Order blood tests
• Do an electrocardiogram (ECG or EKG)
• Do an ECG while you are exercising—this is called a stress test

Other tests may be done by a cardiologist (heart doctor). Longer term testing of your heart can be done with monitors you either wear for a short time or have implanted in your chest for a long time. Examples of longer term testing methods include:

• Holter monitor—24-48 hours
• Event monitor—up to 30 days
• Implantable loop recorder—about 3 years 

More advanced tests may be done by a cardiologist or electrophysiologist. (An electrophysiologist specializes in the heart’s electrical system.)

• Electrophysiology (EP) study
• Echocardiogram
• Magnetic resonance imaging (MRI)
• Computed tomography (CT) scan

Read more about each type of diagnostic test.

Will I need more than one diagnostic test?

Yes, many people need more than one test to diagnose atrial fibrillation. If you do have atrial fibrillation, a more advanced test might be done as part of treatment. For instance, if you have a catheter ablation, an EP study is done to see exactly where the atrial fibrillation begins in the heart. This allows the doctor to know precisely where to apply the treatment.

Which type of doctor should I see for atrial fibrillation?

Most people will start by talking about symptoms with their primary health care provider. But for proper treatment of atrial fibrillation, you should see a cardiologist or electrophysiologist. (A cardiologist specializes in the heart. An electrophysiologist specializes in the heart’s electrical system.) Many people with atrial fibrillation see both types of specialists.

Where does atrial fibrillation usually begin in the heart? 

It varies from one person to another. But there are 3 general areas where atrial fibrillation often begins:

• Pulmonary veins: These are the veins that bring oxygen-rich blood from the lungs to the heart's left atrium.
• Posterior (back) wall of the atrium: The muscle tissue fibers here can make people prone to atrial fibrillation.
• The left atrial appendage (LAA): This is a small pouch of heart tissue at the top of the left atrium. 

See images of these 3 areas of the heart.

What are the causes of atrial fibrillation?

Cells at the top of the heart create electrical signals that travel along pathways in the heart. When the electrical pathways are working properly, you have a normal heart rhythm. The electrical pathways allow the heart to pump blood to all parts of the body. But sometimes the electrical signals go awry, and the heart beats abnormally. Atrial fibrillation is the most common abnormal heart rhythm.

Certain health conditions or lifestyle choices put some people at higher risk for atrial fibrillation. Read the following 2 Q&As for more information. 

What medical problems put people at higher risk for atrial fibrillation?

These medical conditions put people at higher risk for atrial fibrillation:

• Diabetes
• Sleep apnea
• Overactive thyroid
• Infection
• Obesity

There are also cardiovascular (heart and blood vessel) problems that raise the risk for atrial fibrillation:

• High blood pressure 
• Heart valve disease
• Coronary artery disease
• Previous heart attack
• Congenital heart disease (congenital means present at birth)
• Heart failure

Read more about all of these health issues and how they can lead to atrial fibrillation.

Can other things trigger atrial fibrillation? 

Yes, and you have no control over a couple of these factors:

• Age: people over 60 are at higher risk
• Family history and genetics

Stress is another factor. It’s important to control stress as much as you can. Other things that can trigger atrial fibrillation are related to choices people make:

• Drinking alcohol, especially drinking to excess
• Drinking caffeine
• Smoking
• Skipping your heart medications
• Taking stimulants (for instance, certain diet pills)
• Taking street drugs, which are very dangerous for the heart

Learn more about these factors.

Does atrial fibrillation put me at higher risk for stroke?

Yes, someone with atrial fibrillation is 5 times more likely to have a stroke.⁶ Atrial fibrillation causes the atria to beat so fast that they cannot contract fully, to properly circulate blood to the rest of the heart. This leaves blood pooling in the atria, instead of flowing into the ventricles. When blood pools, it can clot. If a blood clot travels to the brain, it can cause a stroke. Find out more, such as who may be at especially high risk.

How might atrial fibrillation increase the chance of heart failure? 

Atrial fibrillation causes physical changes in the heart. The walls of the atria become scarred, stretched out, and more stiff than in a healthy heart. These changes lead to uncoordinated pumping of the atria and ventricles. This uncoordinated pumping can contribute to heart failure. Read more about how atrial fibrillation may lead to heart failure. 

Are there other health problems associated with atrial fibrillation?

Yes, atrial fibrillation can also lead to long-term fatigue as well as dementia. There may be other changes in lifestyle that impact health too: many hospital or clinic visits, and too little activity due to fatigue. All of these issues can diminish a person’s quality of life. As a result, some people may develop anxiety or even depression. Learn more details about these other health problems.