Atrial fibrillation (AF or afib) is a type of heart rhythm disorder, or arrhythmia. It causes your heart to beat irregularly and can significantly increase the heart rate, leading to your heart’s upper and lower chambers not working together properly, according to the National Heart, Lung, and Blood Institute. (1)
Afib begins in the upper chambers of your heart, known as the atria. Fibrillation refers to a rapid, irregular heartbeat.
While a normal resting heart rate is 60 to 100 beats per minute (bpm), atrial fibrillation can cause your atria to beat 300 to 600 times per minute, per the Cleveland Clinic. (2)
Atrial fibrillation can lead to a number of symptoms, including fatigue, dizziness, chest pain, shortness of breath, and heart palpitations. However, in some people, the condition doesn’t cause any symptoms.
Regardless of whether or not it causes symptoms, afib can put you at higher risk for a stroke. As a result, it’s important to get treatment for afib and manage your condition to try to prevent dangerous complications. (1)
Signs and Symptoms of Atrial Fibrillation
Atrial fibrillation causes noticeable symptoms in many people, but some experience no symptoms at all.
If you do experience symptoms, they may include: (1,3)
- Heart palpitations (racing or pounding heart, noticeably irregular heartbeat)
- Chest pain
- Reduced ability to exercise
- Difficulty breathing, especially while lying down or during activity
- Dizziness or fainting
Your symptoms may range from subtle to very noticeable, and they may change over time.
The timing and details of your symptoms can be important to help your doctor diagnose and treat your afib. It’s important to keep track of your symptoms by noting when they occur, how long they last, how severe they are, and what you were doing when they started. (1)
Causes and Risk Factors of Atrial Fibrillation
With a normal heartbeat, the two upper chambers of your heart (known as the atria) electrically activate and contract, then the two lower chambers (ventricles) do the same.
This allows your atria to pump blood into your ventricles, and for your ventricles to pump blood to your lungs (right side) and the rest of your body (left side).
In atrial fibrillation, many different electrical impulses happen all at once in your atria, which causes very fast and disorganized contractions. This means your atria can’t pump blood effectively into your ventricles.
Because of the disorganized electrical impulses that begin in your atria, your ventricles can also contract very quickly and irregularly. As a result, they don’t pump blood as effectively to your body. (2)
Many people with afib have an underlying heart condition or have experienced a past event that has altered the heart's electrical or mechanical function. These conditions include: (3)
- High blood pressure
- Heart valve disease
- Coronary artery disease (CAD)
- Heart attack
- Heart surgery
- Congenital heart defects
Other health conditions may also increase the risk of developing afib, including: (1,3)
- Chronic kidney disease
- Hyperthyroidism (overactive thyroid)
- Lung diseases
- Sarcoidosis (inflammatory disease that affects organs)
- Sleep apnea
- Venous thromboembolism (blood clot)
- Viral infections
In some people with afib, an underlying cause is never identified.
Some factors you can’t control may increase the risk of developing afib, including the following:
- Older age (especially 65 or older)
- Family history of afib
- European ancestry
Certain aspects of your lifestyle may also contribute to afib, such as: (1)
- Drinking alcohol
- Using recreational stimulant drugs (such as cocaine)
- Extreme exercise
- Lack of physical activity
How Is Atrial Fibrillation Diagnosed?
Your doctor will diagnose or rule out afib based on:
- Your symptoms and medical history
- A physical exam
- Diagnostic tests
In addition to asking about your symptoms, your doctor will probably ask you about your family history of heart conditions, your diet and exercise habits, and other risk factors for heart disease.
If your doctor suspects that you have afib or another serious heart condition, you can expect to undergo an examination of your heart and lungs.
In this examination, your doctor will:
- Listen to your heartbeat and breathing
- Check your pulse (heart rate)
- Measure your blood pressure
- Check for swelling in your legs and feet (possible signs of heart failure or an enlarged heart)
- Look for signs of hyperthyroidism (overactive thyroid), such as an enlarged thyroid gland (1)
To help diagnose atrial fibrillation, your doctor may order a number of tests. Most of these tests are designed to analyze your heart rhythm or heart rate in a specific way.
Tests for diagnosing afib may include:
Electrocardiogram (ECG or EKG) This test involves wearing sensors on your chest and arms to record the electrical activity of your heart.
An ECG is the main test for diagnosing afib. It can be done in your doctor’s office in a matter of minutes, and your doctor will usually be able to analyze your results right away.
Holter Monitor This is a type of portable ECG. It involves wearing sensors that connect to a device, which you carry in your pocket or wear attached to a shoulder strap.
A Holter monitor records your heart’s activity, most commonly for 24 to 48 hours, giving your doctor a more complete picture of your heart rhythm.
Event Recorder or Ambulatory Telemetry Monitor These are other types of portable ECGs that are typically worn for a much longer period, from a few weeks to a month.
Whenever you experience symptoms that may indicate a fast or irregular heartbeat, you push a button on the recorder that activates its data storage function. A few minutes of your heart’s electrical activity, both before and after you press the button, are then stored.
Echocardiogram This is an ultrasound of your heart, which uses sound waves to create a video image for your doctor to analyze.
Your doctor or another healthcare professional will hold a device called a transducer over your chest, which both sends and receives sound waves as they bounce off your heart. You won’t feel these sound waves.
Less commonly, your doctor may recommend an echocardiogram that involves inserting a flexible tube containing a tiny transducer down your throat. This is known as a transesophageal echocardiogram.
This type of echocardiogram can produce more detailed images of your heart, which may help your doctor detect blood clots or other problems.
Blood Tests Your doctor may order blood tests to check for thyroid problems or other conditions that could contribute to afib.
Chest X-Ray Your doctor may order an X-ray of your heart and lungs to check for other conditions that might be causing or contributing to your symptoms. (2,3)
Prognosis of Atrial Fibrillation
While atrial fibrillation is always considered a serious condition, it sometimes resolves on its own and doesn’t lead to any complications.
At the other end of the spectrum, atrial fibrillation may be permanent and resistant to treatment, leading to a high risk of serious complications.
If you’re diagnosed with afib, your outlook may depend on known or suspected causes, how often you experience it, and whether it causes noticeable symptoms. (1)
Duration of Atrial Fibrillation
In some people, atrial fibrillation goes away on its own. In others, it’s a problem that lasts for years, and it may get worse over time.
Afib can be intermittent (known as paroxysmal), coming and going in a way that seems random or only when you do certain activities.
An episode of this kind of afib usually lasts less than 24 hours, but may last as long as a week. (1)
You may need treatment for paroxysmal atrial fibrillation, or it may happen infrequently enough that your doctor recommends just monitoring your condition.
Afib can also be persistent, meaning that it lasts for longer than a week. This kind of afib usually requires treatment.
Long-term persistent atrial fibrillation is defined as an abnormal heart rhythm that lasts over a year without interruption.
If a normal heart rhythm can’t be restored after multiple treatments, your afib may be considered permanent. In this case, you may need to take medication to prevent the heart rate from being too fast. (1,3)
Prevention of Atrial Fibrillation
A number of lifestyle changes may help prevent atrial fibrillation, or help treat the condition if you have it already. These steps include: (2,3)
- Avoiding activities that trigger your afib
- Following a heart-healthy diet
- Not smoking
- Getting enough exercise
- Maintaining a healthy weight
- Limiting alcohol
- Limiting caffeine
- Reducing or coping with stress
- Using cough and cold medications with caution (they may contain stimulants)
You should also make sure you’re effectively treating or controlling existing health conditions that may lead to afib, such as sleep apnea, diabetes, or high blood pressure. (2)
Diet and Atrial Fibrillation
Following the right diet may help you decrease the frequency of afib episodes, or reduce your risk of developing the condition in the first place.
Eating too much salt, for example, can raise your blood pressure, putting you at greater risk for afib.
Caffeine is also a common culprit, as it can raise your heart rate and make your heart’s impulses more erratic.
Pros and Cons of Vegetables for Afib Heart Health
Alcohol, even in quantities that don’t seem excessive, can trigger an afib episode and should be consumed in moderation or avoided altogether.
Even foods with a healthy reputation, such as leafy green vegetables and kimchi, may cause problems depending on the specifics of your heart health.
Mental Health and Atrial Fibrillation
It’s well known that people with afib are at higher risk for depression and anxiety, possibly due at least in part to the stress and uncertainty of living with the condition.
But the link between afib and depression may also work in the opposite direction, with symptoms of depression raising the risk for developing afib in the future.
It’s possible that taking steps to address your mental health and well-being — including both professional help and self-care measures, like yoga and exercise — may reduce your risk of afib and other heart conditions.
If you think you might be depressed, a mental health professional can help make sure you get the evaluation and treatment you need.
Find Out More About the Link Between Afib and Depression
Research and Statistics: How Many People Have Atrial Fibrillation?
It’s estimated that about 5.3 million people in the United States have atrial fibrillation, according to a study published in April 2018 in the journal PLoS One. (4) Nearly 700,000 of these cases are undiagnosed.
The rate of afib is about 10 percent in adults ages 65 and older, and just under 1 percent in adults ages 18 to 64.
Because the risk for afib increases as you get older, and women tend to live longer than men, more women than men have the condition.
Related Conditions of Atrial Fibrillation
Atrial fibrillation is a type of arrhythmia, or irregular heart rhythm. Other arrythmias include:
Atrial Flutter This condition is similar to afib, except the rhythm in the heart’s upper chambers is somewhat more organized. Atrial flutter can become atrial fibrillation, and vice versa.
Supraventricular Tachycardia This broad term refers to many arrhythmias that can develop above the heart’s lower chambers, which may cause episodes of heart palpitations that start and end suddenly.
Ventricular Fibrillation This condition is similar to afib, but affects the heart’s lower chambers (ventricles). Since these chambers pump blood to the entire body, it’s extremely serious and can be fatal if normal rhythm isn’t restored within a few minutes.
Long QT Syndrome This heart disorder carries a risk of fast, chaotic heartbeats, which may cause fainting and may be life-threatening, according to the Mayo Clinic. (8)
Resources We Love
Favorite Websites for Essential Afib Information
American Heart Association
The American Heart Association is a leading patient and physician organization in the United States for heart disease and stroke prevention and treatment. This site has information to help you understand an afib diagnosis, treatment options, and lifestyle changes that can help get the condition under control.
Founded by heart disease survivor Mellanie True Hills, StopAfib.org provides atrial fibrillation prevention and treatment information and resources.
Atrial Fibrillation Association
This nonprofit organization provides information and support to people living with atrial fibrillation. It also has physician-reviewed fact sheets on many afib drugs.
Heart Rhythm Society
Afib is just one of several heart rhythm conditions listed on this website, which provides educational information on heart rhythm conditions as well as the latest science and research.
The American College of Cardiology, which is the professional association for cardiologists, offers many consumer resources on heart disease, including a section for afib news with studies and government reports.
Favorite Afib Online Support Networks
This online community, supported by the American Heart Association and StopAfib.org, helps people with afib meet others like them and share their experiences, along with prevention and treatment strategies. It hosts forums on a variety of afib-related topics.
Atrial Fibrillation Support Forum
If you’re on Facebook, you can join this open group where people share experiences and the latest afib news. This discussion group is a great place to find online support and a community of people living with afib.
Favorite App to Detect Afib
FibriCheck is an easy-to-use smartphone app to detect atrial fibrillation that was cleared by the U.S. Food and Drug Administration (FDA) in 2018. A registration fee and annual subscription is required to use the app. Some insurers may reimburse some or all of the cost.
Editorial Sources and Fact-Checking
- Atrial Fibrillation. National Heart, Lung, and Blood Institute. March 12, 2019.
- Atrial Fibrillation (Afib). Cleveland Clinic. July 18, 2019.
- Atrial Fibrillation. Mayo Clinic. June 20, 2019.
- Turakhia MP, Shafrin J, Bognar K, et al. Estimated Prevalence of Undiagnosed Atrial Fibrillation in the United States. PLoS One. April 12, 2018.
- Atrial Fibrillation. Centers for Disease Control and Prevention. May 4, 2020.
- Magnani JW, Norby FL, Agarwal SK, et al. Racial Differences in Atrial Fibrillation-Related Cardiovascular Disease and Mortality. JAMA Cardiology. July 2016.
- Mou L, Norby FL, Chen LY, et al. Lifetime Risk of Atrial Fibrillation by Race and Socioeconomic Status. Circulation: Arrhythmia and Electrophysiology. July 2018.
- Heart Arrhythmia. Mayo Clinic. August 9, 2020.