About atrial fibrillation (afib)

What is atrial fibrillation (afib)?

Atrial fibrillation (AFib) facts

  • Atrial fibrillation (also referred to as AFib) is the most common type of abnormal heart rhythm.
  • AFib is caused by abnormal electrical discharges (signals) that generate chaotically throughout the upper chambers of the heart (atria).
  • AFib reduces the ability of the atria to pump blood into the ventricles, and usually causes the heart to beat too rapidly.
  • One-half million new cases of atrial fibrillation are diagnosed every year in the U.S., and billions of dollars are spent annually on its diagnosis and treatment.
  • Symptoms of atrial fibrillation include:
    • palpitations,
    • dizziness,
    • fainting,
    • weakness,
    • fatigue,
    • shortness of breath, and
    • chest pain.
    • Some people have no AFib symptoms, however.
  • Complications of atrial fibrillation include heart failure and stroke.
  • Atrial fibrillation can be diagnosed by physical examination, electrocardiogram, Holter monitor, or patient-activated event recorder.
  • Treatment of AFib is directed toward controlling underlying causes, slowing the heart rate and/or converting the heart to normal rhythm, and stroke prevention using blood-thinning medications.
  • Medications are commonly used in the longer term to control or prevent recurrence of AFib, but medications may not be effective and may have intolerable side effects.
  • Electrical cardioversion is successful in over 95% of patients with AFib, but 75% of patients have a recurrence of AFib within 1 to 2 years.
  • Some doctors may leave patients in AFib for the longer term provided the heart rate is under control, blood flow is adequate, and blood is adequately thinned with medications.
  • Non-medication treatments of atrial fibrillation include pacemakers, AV node ablation, atrial defibrillators, and the Maze procedure.
  • Pulmonary vein isolation shows promise for the treatment of atrial fibrillation and has a high rate of success; however, longer-term experience is necessary.

What are the symptoms for atrial fibrillation (afib)?

Atrial fibrillation may be:

  • Occasional (paroxysmal atrial fibrillation). A-fib symptoms come and go, usually lasting for a few minutes to hours. Sometimes symptoms occur for as long as a week and episodes can happen repeatedly. Symptoms might go away on their own. Some people with occasional A-fib need treatment.
  • Persistent. With this type of atrial fibrillation, the heart rhythm doesn't go back to normal on its own. If a person has A-fib symptoms, cardioversion or treatment with medications may be used to restore and maintain a normal heart rhythm.
  • Long-standing persistent. This type of atrial fibrillation is continuous and lasts longer than 12 months.
  • Permanent. In this type of atrial fibrillation, the irregular heart rhythm can't be restored. Medications are needed to control the heart rate and to prevent blood clots.

What are the causes for atrial fibrillation (afib)?

To understand the causes of A-fib, it may be helpful to know how the heart typically beats.

The typical heart has four chambers — two upper chambers (atria) and two lower chambers (ventricles). Within the upper right chamber of the heart (right atrium) is a group of cells called the sinus node. The sinus node is the heart's natural pacemaker. It produces the signal that starts each heartbeat.

In a regular heart rhythm:

  • The signal travels from the sinus node through the two upper heart chambers (atria).
  • The signal passes through a pathway between the upper and lower chambers called the atrioventricular (AV) node.
  • The movement of the signal causes your heart to squeeze (contract), sending blood to your heart and body.

In atrial fibrillation, the signals in the upper chambers of the heart are chaotic. As a result, the upper chambers shake (quiver). The AV node is then bombarded with signals trying to get through to the lower heart chambers (ventricles). This causes a fast and irregular heart rhythm.

The heart rate in atrial fibrillation may range from 100 to 175 beats a minute. The normal range for a heart rate is 60 to 100 beats a minute.

Causes of atrial fibrillation

Problems with the heart's structure are the most common cause of atrial fibrillation. Possible causes of atrial fibrillation include:

  • Coronary artery disease
  • Heart attack
  • Heart defect that you're born with (congenital heart defect)
  • Heart valve problems
  • High blood pressure
  • Lung diseases
  • Physical stress due to surgery, pneumonia or other illnesses
  • Previous heart surgery
  • Problem with the heart's natural pacemaker (sick sinus syndrome)
  • Sleep apnea
  • Thyroid disease such as an overactive thyroid (hyperthyroidism) and other metabolic imbalances
  • Use of stimulants, including certain medications, caffeine, tobacco and alcohol
  • Viral infections

Some people who have atrial fibrillation have no known heart problems or heart damage.

What are the risk factors for atrial fibrillation (afib)?

Things that can increase the risk of atrial fibrillation (A-fib) include:

  • Age. The older a person is, the greater the risk of developing atrial fibrillation.
  • Heart disease. Anyone with heart disease — such as heart valve problems, congenital heart disease, congestive heart failure, coronary artery disease, or a history of heart attack or heart surgery — has an increased risk of atrial fibrillation.
  • High blood pressure. Having high blood pressure, especially if it's not well controlled with lifestyle changes or medications, can increase the risk of atrial fibrillation.
  • Thyroid disease. In some people, thyroid problems may trigger heart rhythm problems (arrhythmias), including atrial fibrillation.
  • Other chronic health conditions. People with certain chronic conditions such as diabetes, metabolic syndrome, chronic kidney disease, lung disease or sleep apnea have an increased risk of atrial fibrillation.
  • Drinking alcohol. For some people, drinking alcohol can trigger an episode of atrial fibrillation. Binge drinking further increases the risk.
  • Obesity. People who have obesity are at higher risk of developing atrial fibrillation.
  • Family history. An increased risk of atrial fibrillation occurs in some families.

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