What Is Atrial Fibrillation?

Medically Reviewed by James Beckerman, MD, FACC on November 07, 2022
13 min read

Atrial fibrillation, or AFib, is a quivery, fluttery heartbeat. You might also hear the doctor call it arrhythmia. It means your heart’s normal rhythm is out of whack. Because your blood isn't moving well, you're more likely to have heart failure. That's when your heart can't keep up with your body’s needs. Blood can also pool inside your heart and form clots. If one gets stuck in your brain, you can have a stroke.

What happens in AFib? Normally, the top part of your heart (the atria) squeezes first, then the bottom part (the ventricles). The timing of these contractions is what moves the blood. When you have AFib, the electrical signals that control this process are off-kilter. Instead of working together, the atria do their own thing.

AFib doesn’t so much have types as it has durations. Doctors classify it by how long it lasts, or what causes it. Yours could change over time. Your treatment will depend on which you have.

Paroxysmal Atrial Fibrillation. This is an episode of atrial fibrillation that lasts less than a week. You might feel it happening for a few minutes or for several days. You may not need treatment with this type of AFib, but you should see a doctor.

You could hear it nicknamed “holiday heart syndrome.” This refers to AFib that follows a bout of heavy drinking. If your heart isn’t used to all this different activity, it may go into AFib. It also happens sometimes when you’re under extreme stress.

Persistent Atrial Fibrillation. Persistent AFib usually starts as short-term AFib (paroxysmal AFib). Usually, this lasts longer than a week. You’re more likely to get persistent AFib if you’re:

It could stop on its own, or you may need medicine or treatment to stop it. Doctors can use medicine to treat this type of AFib. If that doesn’t work, they might use a low-voltage current to reset your heart’s rhythm to normal. It’s called electrical cardioversion. Doctors usually do this procedure in a hospital while you’re sedated, so you won’t feel anything. You can go home after it’s done, but someone else will have to drive you.

Long-Standing Persistent Atrial Fibrillation. This means your AFib has lasted for more than a year and doesn’t go away. Medicine and treatment like electrical cardioversion may not stop the AFib. Doctors can use another kind of treatment, such as ablation (which burns certain areas of your heart’s electrical system) to restore your normal heart rhythm.

Permanent (Chronic) Atrial Fibrillation. This can’t be corrected by treatments. If you have this type, you and your doctor will decide if you need long-term medication to control your heart rate and lower your odds of having a stroke.

Valvular Atrial Fibrillation. This type affects people who have an artificial heart valve or valve disease like valvular stenosis (when one of your heart valves stiffens), or regurgitation (a valve isn’t closing property, which lets some blood flow the wrong way). Your chance of getting valvular AFib rises if you have mitral valve disease or artificial heart valves.

Nonvalvular Atrial Fibrillation. This is atrial fibrillation that isn’t caused by a problem with a heart valve. It’s caused by other things, such as high blood pressure or an overactive thyroid gland. Doctors don’t always know what the cause is.

You're more likely to get nonvalvular AFib if you:

  • Are older
  • Have had high blood pressure for many years
  • Have heart disease
  • Drink large amounts of alcohol
  • Have a family member with AFib
  • Have sleep apnea

Both valvular and nonvalvular AFib can cause blood to pool in your heart, which raises your risk of complications like blood clots and strokes. Medicines and other treatments can lower your chances of having these complications.

Whether AFib is valvular or nonvalvular determines the type of medicine your doctor will prescribe to help lower your odds of having a stroke.

Acute Onset Atrial Fibrillation. This rapid, chaotic heartbeat comes on quickly and goes away quickly. It usually resolves itself in 24 to 48 hours. Causes include age, cardiovascular disease, alcohol abuse, diabetes, and lung disease.

Postoperative Atrial Fibrillation. This is the most frequent complication of cardiovascular surgery. It boosts your odds of heart failure and stroke, a brain injury that results from a blood clot blocking blood flow in your brain.

Doctors have many ways to treat atrial fibrillation, no matter which type you have. If you have symptoms, see your doctor to discuss what will be best for you.

More than 2 million Americans have AFib. It's more common in people 60 and older.

Other heart problems can make it more likely:

People with certain medical conditions have a greater chance, too, and at least 1 in 10 people with AFib have no other heart problems:

  • Long-term lung disease (such as COPD)
  • Overactive thyroid gland
  • Sleep apnea
  • A blood clot in your lung, called a pulmonary embolism

Medicines (including adenosine, digitalis, and theophylline) can raise the chance of having AFib.

Sometimes, it's linked to:

  • Heavy alcohol, caffeine, or drug use
  • Infections
  • Genetics
  • Imbalances in your electrolytes


When your heart is in AFib, you might feel:

  • Like your heart is racing or fluttering in your chest (palpitations)
  • Fatigued or weak
  • Dizzy or lightheaded
  • Chest pain or pressure
  • Short of breath

If you have these symptoms, call your doctor and make an appointment as soon as possible. If they last more than 24 hours, go to the hospital.

Sometimes it doesn't cause any symptoms. If you're at risk, talk to your doctor about your chances for having AFib, and get regular checkups.

The main thing your doctor wants to see is the electrical activity in your heart. They will probably do some tests to see what’s going on. Tests for atrial fibrillation include:

  • Blood tests to check your thyroid, liver, and kidneys
  • Electrocardiogram (EKG) to record how fast your heart is beating and the timing of electrical signals that pass through it. A nurse or technician will place about 12 small, sticky sensors on your chest. Wires connect them to a machine that takes the measurements.
  • Chest X-ray to make sure lung disease isn’t the cause of your problems
  • Echocardiogram, which uses sound waves to make a video of your heart working
  • CT scans, special X-rays that make a 3D picture of your heart
  • MRI, which uses magnets and radio waves to create snapshots and videos of your heart
  • Exercise stress test to see how your heart works when you’re active. You might walk on a treadmill or ride a stationary bike while wearing sensors connected to an EKG machine.

And the doctor might use some special gadgets to learn more about your heartbeat such as:

Holter monitor: Your doctor may want you to wear this gadget for a few days while you go about your regular activities. It's like a mobile EKG that records data from your heart 24/7. It helps your doctor spot signs of an arrhythmia. If your AFib symptoms come and go, you may need a different kind of monitor for a longer time.

Depending on how severe your symptoms are, your doctor may recommend medications, surgery, or even a pacemaker to get and keep your heart in a normal rhythm.

Medication:Medications are typically the first things doctors try to treat atrial fibrillation. Various drugs can help control your heart's rhythm, slow your heart down, and help prevent blood clots that might lead to a stroke.

Your doctor can give you drugs that will:

  • Slow your heart rate and ease the strength of contractions (beta-blockers and calcium channel blockers)
  • Bring your heart's rhythm back to normal (sodium and potassium channel blockers)
  • Prevent blood clots ("blood thinners," or anticoagulants and antiplatelets)

Medical procedures: If medications don’t work, your doctor will probably try one of these to reset your heart’s rhythm:

Electrical cardioversion: They'll stick special pads to your chest to send an electric shock to your heart. You won't feel it because you'll be asleep under general anesthesia.

Ablation: They'll make a cut in one of your blood vessels and run a small tube through it and into your heart. Your doctor will then use a laser, radio waves, or extreme cold to burn off the tissue on the surface of your heart that's causing the problem. This creates scar tissue that doesn't pass the off-beat signals. Some hospitals offer robotic-assisted surgery that uses smaller cuts and allows for greater precision. Your doctor will put a video camera or tiny robot into your chest. It’ll guide the creation of scar tissue that may help keep your heartbeat at the right pace.

Maze procedure: If you're having open heart surgery for another reason, your doctor might do this. It’s similar to ablation. Your doctor will create a maze of scar tissue on the part of the heart that relays the electrical signals that control your heartbeat. The scar tissue created by a maze procedure stops the wonky signals that lead to an irregular heartbeat and helps get your heart back on track. Your doctor might consider maze surgery if:

  • AFib medications don't control your symptoms, or they cause serious side effects.
  • You have AFib and are having heart surgery for other reasons. For instance, the surgery may be to treat valve disease or blocked coronary arteries.

Mini maze: Most people with AFib don’t need open-heart surgery. That’s where this minimally invasive option comes in. You might hear it called Cox maze IV. This is also similar to ablation, but the doctor will make three or four small cuts in your side and put tubes, surgical tools, and a tiny camera into them.

Convergent procedure: This pairs catheter ablation with a mini maze. One doctor uses radiofrequency ablation in the pulmonary vein, and a surgeon makes a small cut under your breastbone to use radiofrequency energy on the outside of your heart.

Pacemaker: Will help prevent your heart from beating too slowly. If you take medicine to lower your heart rate, you may need one as a backup. You'll have minor surgery to put the small device under your skin. It runs on batteries and sends little electrical bursts to your heart when it beats too slowly.

You can protect your heart by the choices you make in your daily life too.

Eat healthy food. Get plenty of fresh vegetables and fruits, along with whole grains and lean protein. Limit alcohol and caffeine.

Quit smoking. It can double your risk of AFib.

Stop drinking. It can raise your odds of AFib. How much depends on how much you drink. And it can affect the way your blood thinners work.

Exercise. It’s good for you and your heart. It helps keep your muscles strong, your blood moving, and your weight in check. It even helps you sleep. And people with atrial fibrillation who exercise tend to have fewer episodes of arrhythmia, are less likely to be hospitalized, and have a higher quality of life. Talk to your doctor about the best activities for you, so you don't overdo it.

Check labels. Over-the-counter products like cold medications could have ingredients that will speed up your heart rate.

Lower your stress.Stress can make the condition worse by speeding up your heart rate. Strong emotions like anger, fear, and anxiety could have the same effect.

So it's important to take care of yourself. Find something that gets your mind off your worries and puts you in a good mood. Yoga, music, and time management strategies might ease some tension.

AFib can cause serious health problems. Your doctor has treatments to put your heart back into a normal rhythm and prevent complications.

Stroke. Untreated AFib and valve disease each make you more likely to have blood clots and stroke. Having the two conditions together raises your risk even more.

The odds of having ischemic stroke -- the type caused by a blockage in blood flow to the brain -- are five times higher in people with nonvalvular AFib. That risk is 17 times higher in people with mitral valve stenosis.

Normally when your heart beats, the two upper chambers -- called atria -- squeeze and push blood into the two lower chambers -- called ventricles. In AFib, the atria quiver instead of squeezing strongly. So they push only some of the blood into the ventricles.

That means blood can pool inside the heart. Clumps of blood called clots can form there, too.

A clot that forms in the atria can travel to the brain. If it gets stuck in an artery, it can block blood flow and cause a stroke.

AFib medicines bring your heart back into a normal rhythm, prevent blood clots from forming, and lower the odds you’ll have a stroke. A measure called your CHADS2 score can help your doctor figure out how likely you are to have a stroke -- and decide if you need to take something to help prevent one. It’s basically a series of questions where each letter in the name represents something that may raise your chances of having a stroke.

High blood pressure can also lead to strokes. So it’s even more important to keep your blood pressure in a healthy range with a nutritious diet, exercise, and medicine if you need it.

Cardiomyopathy. AFib makes the ventricles beat faster to push blood out of the heart. Beating too fast for a long time can make the heart muscle too weak to pump enough blood to your body. This is called cardiomyopathy.

Medicines for AFib like beta-blockers and calcium channel blockers slow your heart rate. These drugs can help prevent cardiomyopathy.

Heart Failure. AFib prevents your heart from pushing out blood as well as it should. After a while, the effort of pumping could make your heart so weak, it can't send out as much blood as your body needs. This is called heart failure.

Blood can get backed up in the veins of your lungs and cause fluid to build up there. That causes symptoms like fatigue and shortness of breath.

Heart failure can also lead to AFib. Your heart's rhythm is controlled by electrical signals. For those signals to work well, they need healthy heart tissue.

But heart failure can actually stretch your atria and cause tissue in your heart to thicken and scar. Those changes throw off the electrical signals, and that messes up the heart's rhythm and can cause AFib.

To lower your chances of getting heart failure, manage these four key things:

  • Keep your blood pressure in a normal range.
  • Stay at a healthy weight with diet and exercise.
  • Don't smoke.
  • Control your blood sugar if you have diabetes.

Fatigue. Your body needs a steady supply of oxygen-rich blood to work properly. When your heart can't pump enough, you'll feel tired. If fluid builds up in your lungs because of heart failure, that can add to your exhaustion.

To manage fatigue, balance your activities with periods of rest. Try to get more sleep at night. And exercise as often as you can. A combination of aerobic exercises like walking and biking, plus strength training can give you more energy.

Sleep apnea could be another reason you feel extra tired. This condition, which keeps you from breathing properly when you sleep, can happen along with AFib. Your doctor can test you while you sleep to find out if you have it. One treatment for sleep apnea uses a machine called CPAP, which delivers mild air pressure through a face mask to keep your airways open while you sleep.

Memory Loss. In studies, people with AFib did worse on memory and learning tests than those without the condition. Dementia is also more common in people with AFib.

One possible reason for the link is that AFib raises your odds for a stroke, which can damage the brain. AFib might also affect memory by keeping the brain from getting enough blood.

Your doctor might recommend that you take blood thinners like aspirin and a nonvitamin K oral anticoagulant (NOAC) such as dabigatran (Pradaxa), rivaroxaban (Xarelto), or apixaban (Eliquis). Lifestyle changes that protect your heart -- including maintaining a healthy weight -- could also protect your brain.

High Blood Pressure. If you have atrial fibrillation (AFib), there's a pretty good chance you have high blood pressure too. The two conditions often go together.

When everything's going right, your heart chugs along with a steady rhythm you can keep time to. It pumps blood through your body with just the right touch, and all your cells get the oxygen they need.

But high blood pressure throws a wrench into those works. It means your blood's flowing with more force than normal, so it's pushing hard on your artery walls. If that goes on for too long, the added stress causes damage that can lead to all kinds of problems.

Sometimes AFib goes away on its own. But for many people, it's a long-term problem. Both valvular and nonvalvular AFib are progressive, meaning that over time, symptoms happen more often and last longer.

You might start out with occasional, mild AFib that, years later, doesn't ever seem to go away. And in terms of your health, how fast that happens -- what doctors call "the rate of progression" -- might be more important than how long your AFib episodes last.

Studies on AFib progress and what to do about it are challenging for researchers though, because they don't have a good way to measure progression.

Show Sources


National Heart, Lung, and Blood Institute: “Electrocardiogram,” “Stress Testing,” “Atrial Fibrillation,” “Sleep Apnea,” “CPAP,” "How Does Smoking Affect the Heart and Blood Vessels?"

StopAFib.org: “Mini Maze Procedure (Surgical Ablation),” “Cox Maze III Procedure,” “How Atrial Fibrillation Progresses,” “Maze Procedure (Surgical Ablation),” “Using Electrical Cardioversion for Atrial Fibrillation.”

Heart Rhythm Society: “Types of Ablations,” "Complications from Atrial Fibrillation."

Heart Rhythm: “Smoking and Incidence of Atrial Fibrillation: Results from the Atherosclerosis Risk in Communities (ARIC) Study.”

AFib Matters: “Living With Atrial Fibrillation.”

News release, FDA.

American Heart Association: "Atrial Fibrillation," “What is Atrial Fibrillation (AFib or AF)?” “Ischemic Strokes (Clots),” “Ablation for Arrhythmias,” "Why Atrial Fibrillation Matters," "A Patient's Guide to Taking Warfarin," "Atrial Fibrillation Medications," "What are the Symptoms of Atrial Fibrillation (AFib or AF)?" "Who is at Risk for Atrial Fibrillation (AFib or AF)?" "When the Beat is Off -- Atrial Fibrillation," “Losing weight substantially reduces Atrial Fibrillation,” “Non-surgical Procedures for Atrial Fibrillation (AFib or AF),” “Surgical Procedures for Atrial Fibrillation (AFib or AF),” "Prevention Strategies for Atrial Fibrillation (AFib or AF)," "What is Atrial Fibrillation (AFib or AF)?" "What Is Heart Failure?" "Atrial Fibrillation and Heart Failure," "Smoking & Cardiovascular Disease (Heart Disease)," "What are the Symptoms of Atrial Fibrillation (AFib or AF)?" "High Blood Pressure, Afib and Your Risk of Stroke."

British Heart Foundation: "Your weight and heart disease."

Cleveland Clinic: "What is Atrial Fibrillation?" “Atrial Fibrillation,” "Heart Surgery for Atrial Fibrillation (MAZE)," "Atrial Fibrillation (Afib): Management and Treatment."

American Academy of Family Physicians: "Atrial Fibrillation."

The University of Chicago Medical Center: "Surgical Treatment for Atrial Fibrillation," “Atrial Fibrillation.”

Shea, J. Circulation, May 20, 2008.

Ferri, F. Ferri's Clinical Advisor 2011, 1st ed., Mosby Elsevier, 2010.

Bonow, R. Braunwald's Heart Disease - A Textbook of Cardiovascular Medicine, 9th ed. Saunders Elsevier, 2011.

Task Force for the Management of Atrial Fibrillation. European Heart Journal, October 2010.

Boriani, G.  Vascular Pharmacology, 2016.

Cunningham, J. Pursuing Improved Quality of Life In the Atrial Fibrillation Population: Evidence-Based Practice, University of South Carolina, 2012.

Holding, S. Nursing Times, August 2013.

Judd, S. Omnigraphics, 2014.

McCabe, P.  Journal of Clinical Nursing, 2015.

BMH Clinical Evidence: “Atrial fibrillation (acute onset).”

Journal of Anesthesia: “Management of postoperative atrial fibrillation.”

NYU Langone Health: “Lifestyle Changes for Atrial Fibrillation & Atrial Flutter in Adults,” "Types of Cardiomyopathy & Heart Failure."

UpToDate: “Overview of atrial fibrillation,” “Paroxysmal atrial fibrillation.”

Mayo Clinic: “Atrial fibrillation ablation: Maze,” "Atrial Fibrillation: Diagnosis & treatment," "Atrial Fibrillation: Symptoms & causes," "Mitral valve stenosis: Diagnosis & treatment," "Mitral valve disease: Symptoms & causes," “Cardioversion,” “Atrial fibrillation,” “Reduce your risk of stroke if you have atrial fibrillation,” “Coronary artery disease,” "Atrial Fibrillation," "Heart Failure," "High blood pressure (hypertension)."

Annals of Cardiothoracic Surgery: “A brief overview of surgery for atrial fibrillation.”

Keck School of Medicine of USC: “Robotic-Assisted Maze Surgery.”

Texas Heart Institute: "Maze surgery."

University of Washington School of Medicine and Public Health: "Robotic Maze Procedure for Atrial Fibrillation."

Adventist Heart Institute: "Hybrid Maze, TT Maze, Mini-Maze, Modified Maze or Surgical Ablation -- The Most Advanced Technique to Treat A-Fib."

American College of Cardiology: "2017 AHA/ACC focused update of valvular heart disease guideline," "Patients with AFib Can Prevent Heart Failure with a Few Key Choices," “HAS-BLED Tool -- What is the Real Risk of Bleeding in Anticoagulation?”

American Family Physician: "Diagnosis and treatment of atrial fibrillation."

Archives of Cardiovascular Diseases: "How to define valvular atrial fibrillation?"

CardioSmart: "Atrial Fibrillation Overview," "Living With AFib: Experts and Patients Share 10 Tips," "I Have Atrial Fibrillation: How Active Can I Be?"

European Heart Journal: "What is 'valvular' atrial fibrillation? A reappraisal," “Catheter ablation in patients with persistent atrial fibrillation.”

Journal of the American Heart Association: "Use of direct oral anticoagulants in patients with atrial fibrillation and valvular heart lesions,"  “Prognostic Value of the CHADS2 Score for Adverse Cardiovascular events in Coronary Artery Disease Patients Without Atrial Fibrillation -- A Multi-Center Observational Cohort Study.”

National Stroke Association: "AFib-Stroke Connection."

Penn Medicine: "Do Heart Valve Issues Cause AFib?"

The Open Cardiovascular Medicine Journal: "Stroke prevention in atrial fibrillation and valvular heart disease."

Cedars-Sinai: "Atrial Fibrillation," "Electrophysiology Program Patient Guide: Frequently Asked Questions."

My AFib Experience: “Exercising With Atrial Fibrillation,” “Symptoms of Atrial Fibrillation,” “What Do I Need to Know About Exercise and AFib?”

Expert Reviews in Cardiovascular Therapy: “Persistent atrial fibrillation versus paroxysmal atrial fibrillation: differences in management.”

StopAFib.org: “How Atrial Fibrillation Progresses,” “Maze Procedure (Surgical Ablation),” “Using Electrical Cardioversion for Atrial Fibrillation,” "What to Expect After a Maze Procedure."

Europace: “The Registry of the German Competence NETwork on Atrial Fibrillation: patient characteristics and initial management,” "The definition of valvular and non-valvular atrial fibrillation: results of a physicians’ survey."

University of Michigan, Frankel Cardiovascular Center: “AV Node Ablation.”

European Cardiology: "Atrial fibrillation, cognitive decline and dementia."

Journal of Multidisciplinary Healthcare: "What patients want and need to know about atrial fibrillation."

WebMD: "Doctors: Newer Blood Thinners Best Against A-Fib."

Heart Foundation: “Aspirin.”

Mayo Clinic Health Letter: “CHADS2 score.”

UCSF Cardiology: “Atrial Fibrillation Medication Management.”

Clinical Interventions in Aging: “CHADS2 score has a better predictive value than CHA2DS2-VASc score in elderly patients with atrial fibrillation.”

Circulation: “Renal Dysfunction as a Predictor of Stroke and Systemic Embolism in Patients with Nonvalvular Atrial Fibrillation,” "ACC/AHA/ESC Guidelines for the Management of Patients With Atrial Fibrillation: Executive Summary -- A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients With Atrial Fibrillation), Developed in Collaboration With the North American Society of Pacing and Electrophysiology."

U.S. National Library of Medicine: "Atrial fibrillation in heart failure: what should we do?" "Atrial Fibrillation in Congestive Heart Failure," "Smoking and Incidence of Atrial Fibrillation: Results from the Atherosclerosis Risk in Communities (ARIC) Study."

Harvard Health Publications, Harvard Medical School: "Thyroid disorders and heart conditions: What's the connection?"

National Heart, Lung, and Blood Institute: "Atrial Fibrillation," "Catheter Ablation."

Penn Medicine: "Do Heart Valve Issues Cause AFib?"

Cedars-Sinai: "Electrophysiology Patient Guide: Frequently Asked Questions - Atrial fibrillation."

JACC: Clinical Electrophysiology: "A Systematic Review on the Progression of Paroxysmal to Persistent Atrial Fibrillation: Shedding New Light on the Effects of Catheter Ablation."

Heart: "Heart rate is associated with progression of atrial fibrillation, independent of rhythm."

World Journal of Cardiology: "Prediction of atrial fibrillation development and progression: Current perspectives."

Journal of the American College of Cardiology: "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation."

Clinical Research in Cardiology: "Clinical scores for outcomes of rhythm control or arrhythmia progression in patients with atrial fibrillation: a systematic review."

European Society of Hypertension: "Hypertension and atrial fibrillation: diagnostic approach, prevention and treatment. Position paper of the Working Group 'Hypertension Arrhythmias and Thrombosis' of the European Society of Hypertension."


View privacy policy, copyright and trust info