Atrial Fibrillation

Atrial Fibrillation

Atrial fibrillation (Afib) occurs when the upper two chambers of the heart (the atria) flutter and/or beat out of rhythm with the bottom two chambers of the heart (the ventricles). Afib is fairly common, affecting between 2.7 and 6 million people in the United States. Because the population of the U.S. is aging, the numbers of people with atrial fibrillation is expected to increase. Atrial fibrillation is more common in people age 65 or older, affecting about 9% of this age group. Among people younger than 65, only about 2% have Afib.1 There is no "typical" atrial fibrillation patient outside of age; it affects men and women equally.

Symptoms of Atrial Fibrillation

Some people with atrial fibrillation have no symptoms and are completely unaware that their heart rate is not regular. Others may experience what feels like a fluttering or a fast, pounding or irregular heartbeat, usually over 140 beats a minute. A normal heart rate should be between 60 and 100 beats a minute at rest. You can determine your heart rate by feeling the pulse in your wrist or neck, counting the beats for 10 seconds, and then multiplying that number by six to calculate the number of beats per minute.

People who have atrial fibrillation may also experience these symptoms:

  • Fatigue or tiredness
  • Shortness of breath
  • Lightheadedness
  • Chest pain (angina)

Atrial Fibrillation and Stroke Risk

By itself, Afib is not life threatening, but it can lead to serious complications, and the most serious complication is stroke. People with atrial fibrillation have a five times higher risk of experiencing a stroke, and one out of every six strokes is caused by atrial fibrillation.3 When the atria (the top two chambers of the heart) are not beating efficiently and in rhythm with the ventricles, they do not empty completely of all the blood passing through. This can lead to blood pooling in the atria, which can cause blood clots. If the clots travel to the brain, they can block the blood flowing to the brain, causing a stroke. Within minutes of the blood flow becoming blocked, the brain cells begin to die, and damage can be permanent. Very few people ever come back 100% from a stroke.

People with Afib are also at a higher risk of developing heart failure. Uncontrolled Afib can weaken the heart over time and lead to heart failure, a condition where the heart is simply unable to pump enough blood to meet the body's needs.

Getting an Atrial Fibrillation Diagnosis

A physician will use blood testing (to check for a thyroid disorder), a chest x-ray, a person's medical history, and an electrocardiogram (ECG) to evaluate a patient for atrial fibrillation. An ECG is conducted by attaching small stickers, called electrodes, to the arms and legs to measure the heart's electrical activity. The physician will sometimes want the patient to wear a mobile heart monitor for several days or weeks to measure and analyze the heart's rhythm over a longer period of time. This type of monitoring helps the doctor to finalize the diagnosis of atrial fibrillation and develop a treatment plan.

Types of Atrial Fibrillation

Afib in its early stages can occur sporadically, meaning it can come and go, lasting for just a few minutes or hours, with the heart rhythm returning to normal on its own. This is called occasional or paroxysmal Afib.

Persistent atrial fibrillation is defined as an irregular heart rate that does not return to a normal rhythm on its own.

Longstanding persistent atrial fibrillation lasts for longer than a year, and usually requires treatment (see more about treatment for Afib in the section below).

Treatment of Atrial Fibrillation

The doctor and Afib patient will determine the most appropriate treatment based on how long a person has had Afib, the underlying cause (if known), and the severity of symptoms. Atrial fibrillation treatment has two objectives: to reduce the risk of blood clotting (and thereby reduce the risk of stroke), and to normalize or control the heart rate (how fast it beats) and heart rhythm (how regularly it beats). Medication is available to help with both of these treatment goals, but some people will require what is called electrical cardioversion to return their heart to a normal rhythm. Cardioversion is an electric shock delivered to the heart to reset the rhythm. The treatment plan will also be based on whether the patient has any other issues with their heart, such as having had a previous heart attack. Most people with Afib, and especially those with persistent Afib, should be offered medication called anticoagulants to reduce the risk of blood clots forming. For some people, this medication will be needed for the rest of their lives.

What Causes Atrial Fibrillation?4

Damage to the structure of the heart, or other abnormalities of the heart are the most common cause of atrial fibrillation. Other possible causes include:

  • High blood pressure
  • Atherosclerosis
  • Previous heart attack or heart surgeries
  • Heart valve abnormalities
  • Congenital heart disease (heart disease already present at birth)
  • Hyperthyroidism (overactive thyroid gland)
  • Cardiomyopathy (the heart muscle is diseased and cannot pump effectively)
  • Pericarditis (inflammation of the lining surrounding the heart)
  • Lung diseases, including pneumonia, chronic obstructive pulmonary disease, and lung cancer
  • Sleep apnea
  • Ingestion of stimulants such as medications, caffeine, tobacco, alcohol, or narcotics such as cocaine

Who is Most at Risk For Atrial Fibrillation?

  • Age 65+: approximately 70% of individuals with Afib are between the ages of 65 and 85.2
  • Adults with a family history of atrial fibrillation
  • People with heart disease
  • People with high blood pressure
  • People experiencing chronic conditions such as sleep apnea, thyroid problems, previous heart attack or heart surgeries, diabetes, chronic kidney disease, or lung diseases
  • People who practice binge drinking of alcohol
  • People who are obese, particularly those with a BMI of 25 or higher. You can calculate your BMI here.

Prevention of Atrial Fibrillation4

Living a heart-healthy lifestyle is important to reduce your risk of developing any heart disease, including atrial fibrillation. This includes:

  • Maintaining a healthy weight, and eating a heart-healthy diet along the lines of the DASH diet, which is described here.
  • Cautiously using over the counter medications for colds and coughs, as some contain stimulants that can cause atrial fibrillation episodes
  • Limiting consumption of caffeine and alcohol
  • Do not smoke cigarettes or cigars
  • Reduce stress—intense anger and stress can cause heart rhythm problems


1 Centers for Disease Control and Prevention, Division for Heart Disease and Stroke Prevention,

2 Feinberg WM, Blackshear JL, Laupacis A, Kronmal R, Hart RG. Prevalence, Age Distribution, and Gender of Patients With Atrial Fibrillation: Analysis and Implications. Arch Intern Med. 1995;155(5):469–473. doi:10.1001/archinte.1995.00430050045005;

3 National Blood Clot Alliance,

4 Mayo Clinic, Symptoms and Causes of Atrial Fibrillation,