Atrial fibrillation or flutter
Auricular fibrillation; A-fib; Afib
Atrial fibrillation or flutter is a common type of abnormal heartbeat. The heart rhythm is fast and most often irregular.
A lot of things can make your heart beat faster, like kissing the person you love or watching a scary movie. But sometimes, your heart beats not only faster but also out of rhythm. That can be a problem if this continues over a long period of time and isn't treated. Let's talk about a condition called atrial fibrillation. If you can listen to your heart through a stethoscope, your heart beat should sound something like this, or lub dub, lub dub, lub dub. If you have atrial fibrillation, the top two chambers of your heart contract too quickly, and in an irregular pattern. So what you'd hear if you listened through a stethoscope would be more like this. Atrial fibrillation doesn't just sound funny, this irregular beat can prevent your heart from pumping enough blood out to the rest of your body. Age may cause atrial fibrillation. As you get older, it's more common to have an irregular heartbeat. You're also more likely to have atrial fibrillation if you've had another heart problem, like valve disease, coronary artery disease, or heart failure. Some people get atrial fibrillation because they drink too much alcohol or take certain medicines. To find out you may have atrial fibrillation. You'll feel your heart race and flutter-and not just once in a while, but often. You may also have trouble breathing and feel tired and dizzy. Your doctor can listen for fluttering while listening to your heart with a stethoscope. You may also need a test that records your heart's rhythms, like an ECG, which you have in your doctor's office, or a Holter monitor that you wear around for a day. Your doctor may also prescribe imaging tests to look at your heart and check whether its electrical system is working properly. If you do have atrial fibrillation, your doctor can give you medicine to slow your racing heart. Often, the next step is to restore the normal heart rhythm with an electric shock, a process called Cardioversion. However, if the atria haven't been contracting well for 48 hours or more, blood clots may have formed there. These patients are usually given anti-coagulant medicines before Cardioversion to prevent the clots from moving to the brain and causing a stroke when normal rhythm is restored. If Cardioversion doesn't solve the problem, a procedure called Cardiac ablation can be done to destroy the bad areas of your heart that are causing your heart to beat abnormally. Usually doctors can treat atrial fibrillation so that it becomes a minor nuisance, instead of a big problem. But, the condition can come back, even after it's been treated. If it continues, atrial fibrillation can lead to heart failure. To avoid complications from atrial fibrillation, call your doctor if you're feeling flutters in your chest, and they don't go away.
The interior of the heart is composed of valves, chambers, and associated vessels.
The external structures of the heart include the ventricles, atria, arteries and veins. Arteries carry blood away from the heart while veins carry blood into the heart. The vessels colored blue indicate the transport of blood with relatively low content of oxygen and high content of carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen and low content of carbon dioxide.
Let’s take a closer look inside the heart. The yellow objects are not nerves. They’re actually specialized cardiac muscle cells in the walls of the heart. Their job is to send signals to the rest of the heart muscle and cause a contraction. Together, this group of cells is called the Cardiac conduction system. The main components of the Cardiac conduction system are the SA node, AV node, Bundle of His, Bundle branches, and Purkinje fibers. Let’s follow a signal through the contraction process. The SA node starts the sequence by causing the atrial muscles to contract. That’s why doctors sometimes call it the anatomical pacemaker. From there, the signal travels to the AV node, through the Bundle of His, down the Bundle branches, and through the Purkinje fibers, causing the ventricles to contract. This signal creates an electrical current that can be seen on a graph called an Electrocardiogram, or EKG. Doctors us an EKG as a way of seeing how well the Cardiac conduction system works. Any changes to the EKG can mean serious problems.
The coronary arteries supply blood to the heart muscle. The right coronary artery supplies both the left and the right heart; the left coronary artery supplies the left heart.
The intrinsic conduction system sets the basic rhythm of the beating heart by generating impulses which stimulate the heart to contract.
The heart has four chambers and four main blood vessels that either bring blood to the heart, or carry blood away. The four chambers are the right atrium and right ventricle and the left atrium and left ventricle. The blood vessels include the superior and inferior vena cava. These bring blood from the body to the right atrium. Next is the pulmonary artery that carries blood from the right ventricle to the lungs. The aorta is the body's largest artery. It carries oxygen-rich blood from the left ventricle to the rest of the body. Beneath the tough fibrous coating of the heart, you can see it beating. Inside the chambers are a series of one-way valves. These keep the blood flowing in one direction. Dye injected into the superior vena cava, will pass through all the heart's chambers during one cardiac cycle. Blood first enters the heart's right atrium. A muscle contraction forces the blood through the tricuspid valve into the right ventricle. When the right ventricle contracts, blood is forced through the pulmonary semilunar valve into the pulmonary artery. Then it travels to the lungs. In the lungs, the blood receives oxygen then leaves through the pulmonary veins. It returns to the heart and enters the left atrium. From there, blood is forced through the mitral valve into the left ventricle. This is the muscular pump that sends blood out to the rest of the body. When the left ventricle contracts, it forces blood through the aortic semilunar valve and into the aorta. The aorta and its branches carries the blood to all the body's tissues.
Atrial fibrillation (AF) is the most common sustained arrhythmia in adults. It affects more than 2 million individuals in the United States, and as many as 160,000 new cases are diagnosed each year. The incidence of atrial fibrillation increases with age, and it is often associated with hypertension, valvular and pulmonary disease, metabolic disorders, and coronary artery disease. It is usually triggered by rapid firing from the pulmonary veins, followed by disorganized and asymmetrical impulse through the atria resulting in over 400 beats/min. The ventricles also respond in an irregular way. A serious consequence resulting from AF is clot formation in the atrium, especially when the atria have enlarged and have areas of pooling blood, which subsequently leads to embolism. Risk of thromboembolism is greater in people with diabetes, hypertension, history of embolism, diseases of the valves, and heart failure. In atrial flutter, regular atrial rates range from 250 to 350 beats/min. Most people with atrial flutter have some type of underlying heart problem such as hypertension, coronary artery disease, pericarditis, or valvular heart disease. It can also be caused by a congenital heart defect. Atrial flutter increases the patient’s risk of thromboembolism by 3% per year. Prevention and treatment of atrial flutter should be approached as described for atrial fibrillation. Long-term anticoagulation therapy is recommended for both conditions to reduce the risk of thromboembolism. Radiofrequency catheter ablation is very effective and has minimal risks. It can even be considered as an alternative to drug therapy.
A lot of things can make your heart beat faster, like kissing the person you love or watching a scary movie. But sometimes, your heart beats not only faster but also out of rhythm. That can be a problem if this continues over a long period of time and isn't treated. Let's talk about a condition called atrial fibrillation. If you can listen to your heart through a stethoscope, your heart beat should sound something like this, or lub dub, lub dub, lub dub. If you have atrial fibrillation, the top two chambers of your heart contract too quickly, and in an irregular pattern. So what you'd hear if you listened through a stethoscope would be more like this. Atrial fibrillation doesn't just sound funny, this irregular beat can prevent your heart from pumping enough blood out to the rest of your body. Age may cause atrial fibrillation. As you get older, it's more common to have an irregular heartbeat. You're also more likely to have atrial fibrillation if you've had another heart problem, like valve disease, coronary artery disease, or heart failure. Some people get atrial fibrillation because they drink too much alcohol or take certain medicines. To find out you may have atrial fibrillation. You'll feel your heart race and flutter-and not just once in a while, but often. You may also have trouble breathing and feel tired and dizzy. Your doctor can listen for fluttering while listening to your heart with a stethoscope. You may also need a test that records your heart's rhythms, like an ECG, which you have in your doctor's office, or a Holter monitor that you wear around for a day. Your doctor may also prescribe imaging tests to look at your heart and check whether its electrical system is working properly. If you do have atrial fibrillation, your doctor can give you medicine to slow your racing heart. Often, the next step is to restore the normal heart rhythm with an electric shock, a process called Cardioversion. However, if the atria haven't been contracting well for 48 hours or more, blood clots may have formed there. These patients are usually given anti-coagulant medicines before Cardioversion to prevent the clots from moving to the brain and causing a stroke when normal rhythm is restored. If Cardioversion doesn't solve the problem, a procedure called Cardiac ablation can be done to destroy the bad areas of your heart that are causing your heart to beat abnormally. Usually doctors can treat atrial fibrillation so that it becomes a minor nuisance, instead of a big problem. But, the condition can come back, even after it's been treated. If it continues, atrial fibrillation can lead to heart failure. To avoid complications from atrial fibrillation, call your doctor if you're feeling flutters in your chest, and they don't go away.
Causes
`When working well, the 4 chambers of the heart contract (squeeze) in an organized way.
Electrical signals direct your heart to pump the right amount of blood for your body's needs. The signals begin in an area called the sinoatrial node (also called the sinus node or SA node).
In atrial fibrillation, the electrical impulse of the heart is not regular. This is because the sinoatrial node no longer controls the heart rhythm.
- Parts of the heart cannot contract in an organized pattern.
- As a result, the heart cannot pump enough blood to meet the body's needs.
In atrial flutter, the ventricles (lower heart chambers) may beat very rapidly, but in a regular pattern.
These problems can affect both men and women. They become more common with increasing age.
Common causes of atrial fibrillation include:
- Alcohol use (especially binge drinking)
- Coronary artery disease
- Heart attack or heart bypass surgery
- Heart failure or an enlarged heart
- Heart valve disease (most often the mitral valve)
- Hypertension
- Medicines
- Overactive thyroid gland (hyperthyroidism)
- Pericarditis
- Sick sinus syndrome
Symptoms
You may not be aware that your heart is not beating in a normal pattern.
Symptoms may start or stop suddenly. This is because atrial fibrillation may stop or start on its own.
Symptoms may include:
Exams and Tests
The health care provider may hear a fast heartbeat while listening to your heart with a stethoscope. Your pulse may feel fast, uneven, or both.
The normal heart rate is 60 to 100 beats per minute. In atrial fibrillation or flutter, the heart rate may be 100 to 175 beats per minute. Blood pressure may be normal or low.
An ECG (a test that records the electrical activity of the heart) may show atrial fibrillation or atrial flutter.
If your abnormal heart rhythm comes and goes, you may need to wear a special monitor to diagnose the problem. The monitor records the heart's rhythms over a period of time.
- Event monitor (3 to 4 weeks)
- Holter monitor (24-hour test)
- Implanted loop recorder (extended monitoring)
Tests to find heart disease may include:
- Echocardiogram (ultrasound imaging of the heart)
- Tests to examine the blood supply of the heart muscle
- Tests to study the heart's electrical system
Treatment
Cardioversion treatment is used to get the heart back into a normal rhythm right away. There are two options for treatment:
- Electric shocks to your heart
- Drugs given through a vein
These treatments may be done as emergency methods, or planned ahead of time.
Daily medicines taken by mouth are used to:
- Slow the irregular heartbeat -- These drugs may include beta-blockers, calcium channel blockers, and digoxin.
- Prevent atrial fibrillation from coming back -- These drugs work well in many people, but they can have serious side effects. Atrial fibrillation returns in many people, even while they are taking these medicines.
A procedure called radiofrequency ablation can be used to scar areas in your heart where the heart rhythm problems are triggered. This can prevent the abnormal electrical signals that cause atrial fibrillation or flutter from moving through your heart. You may need a heart pacemaker after this procedure. All people with atrial fibrillation will need to learn how to manage this condition at home.
People with atrial fibrillation will most often need to take blood thinner medicines. These drugs tare used to reduce the risk of developing a blood clot that travels in the body (and that can cause a stroke, for example). The irregular heart rhythm that occurs with atrial fibrillation makes blood clots more likely to form.
Blood thinner medicines include heparin, warfarin (Coumadin), apixaban (Eliquis), rivaroxaban (Xarelto), edoxaban (Savaysa) and dabigatran (Pradaxa). Antiplatelet drugs such as aspirin or clopidogrel may also be prescribed. However, blood thinners increase the chance of bleeding, so not everyone can use them.
Another stroke prevention option for people who cannot safely take these medicines is the Watchman Device, which has recently been approved by the FDA. This is a small basket-shaped implant that is placed inside the heart to block off the area of the heart where most of the clots form. This limits clots form forming.
Your provider will consider your age and other medical problems when deciding which stroke prevention methods are best for you.
Outlook (Prognosis)
Treatment can often control this disorder. Many people with atrial fibrillation do very well with treatment.
Atrial fibrillation tends to return and get worse. It may come back in some people, even with treatment.
Clots that break off and travel to the brain can cause a stroke.
When to Contact a Medical Professional
Contact your provider if you have symptoms of atrial fibrillation or flutter.
Prevention
Talk to your provider about steps to treat conditions that cause atrial fibrillation and flutter. Avoid binge drinking.
References
Calkins H, Tomaselli GF, Morady F. Atrial fibrillation: clinical features, mechanisms, and management. In: Libby P, Bonow RO, Mann DL, Tomaselli GF, Bhatt DL, Solomon SD, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Philadelphia, PA: Elsevier; 2022:chap 66.
Heidenreich PA, Estes NAM 3rd, Fonarow GC, et al. 2020 Update to the 2016 ACC/AHA Clinical Performance and Quality Measures for adults with atrial fibrillation or atrial flutter: A report of the American College of Cardiology/American Heart Association Task Force on Performance Measures. J Am Coll Cardiol. 2021;77(3):326-341. PMID: 33303319
January CT, Wann LS, Calkins H, et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society in collaboration with the Society of Thoracic Surgeons. Circulation. 2019;140(6)e285. PMID: 30686041
Lip GYH, Banerjee A, Boriani G, et al. Antithrombotic therapy for atrial fibrillation: CHEST Guideline and Expert Panel Report. Chest. 2018;154(5):1121-1201. PMID: 30144419
Meschia JF, Bushnell C, Boden-Albala B, et al. Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45(12):3754-3832. PMID: 25355838
Zimetbaum P. Supraventricular cardiac arrhythmias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 58.
Version Info
Last reviewed on: 1/9/2022
Reviewed by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
