Diseases & Conditions

Atrial Fibrillation


Overview, Causes, & Risk Factors

Atrial fibrillation is an abnormal heart rhythm that starts in the upper chambers of the heart.

What is going on in the body?

The top chambers of the heart are called the atria. They feed blood into the lower chambers, called ventricles. In some people, the atria begin to fibrillate, or twitch. This causes the normal, regular beating of the heart to change to a random, chaotic rhythm. This is called atrial fibrillation.

What are the causes and risks of the disease?

Atrial fibrillation is the most common heart rhythm disturbance for which people seek medical attention. It is most common in elderly individuals. It is more common in men than in women.

Risk factors for atrial fibrillation include the following:

  • congestive heart failure, in which the weakened heart fails to pump blood effectively throughout the body
  • coronary artery disease
  • diabetes
  • heart attack
  • heart valve disorders
  • herbal remedies, including ephedra and ginseng
  • high blood pressure
  • hyperthyroidism, or an overactive thyroid gland
  • open heart surgery
  • pulmonary embolism, which is a blockage in the blood supply to the lungs
  • too much alcohol intake

  • Symptoms & Signs

    What are the signs and symptoms of the disease?

    Following are some of the signs and symptoms of atrial fibrillation:

  • chest pain
  • dizziness
  • fainting
  • falling blood pressure
  • fatigue
  • palpitations, or an abnormal awareness of the heart beating in the chest
  • poor exercise tolerance
  • shortness of breath

  • Diagnosis & Tests

    How is the disease diagnosed?

    The diagnosis of atrial fibrillation begins with a medical history and physical exam. The healthcare provider may order tests, including the following:

  • blood tests to rule out problems causing the irregular heart rate
  • chest X-ray, to detect problems in the lungs
  • echocardiogram, which uses ultrasounds to look at blood flow in the heart
  • electrocardiogram, or ECG, which measures the electrical activity of the heart

  • Prevention & Expectations

    What can be done to prevent the disease?

    Atrial fibrillation cannot always be prevented. Medications such as verapamil or diltiazem can be used to control the heart rate once the condition is diagnosed.

    What are the long-term effects of the disease?

    Atrial fibrillation can lead to congestive heart failure. The abnormal atrial rhythm also increases a person's risk for blood clots. The clots can travel to the brain and cause a stroke.

    What are the risks to others?

    Atrial fibrillation is not contagious and poses no risk to others.


    Treatment & Monitoring

    What are the treatments for the disease?

    Treatment of atrial fibrillation depends on many factors. These include duration, underlying causes, and the severity of the person's symptoms. In many cases, atrial fibrillation returns to a normal rhythm within 24 hours without treatment.

    The two main goals of treatment are to control the heart rate and to prevent blood clot problems.

    One treatment for atrial fibrillation is called cardioversion. The healthcare provider uses paddles to deliver an electrical shock to the person's chest. The shock is synchronized with the person's electrical heart activity. Cardioversion can restore the normal heart rhythm. This is typically a planned procedure. Sedation is used for the procedure, but the person will usually be awake.

    Medications such as ibutilide and adenosine given may be given to convert the heart rhythm back to normal. If the normal heart rhythm cannot be restored, other medications can be used to control the more dangerous rhythms. These medications include the following:

  • amiodarone
  • beta-blockers, such as metoprolol or atenolol
  • calcium channel blockers, such as verapamil or diltiazem
  • digitalis
  • procainamide
  • propafenone
  • quinidine
  • Anticoagulants, or blood thinners, may be prescribed to prevent blood clots. If the person is unresponsive to medications, a pacemaker may be inserted.

    If medications are not effective for an individuals' atrial fibrillation, another procedure may be tried. Radiofrequency ablation is used to destroy the small portion of the atria that is causing the abnormal rhythmn. This procedure involves guiding a catheter, or narrow tube, to the problem area. Radiofrequency waves, similar to microwaves, are used to destroy the problem tissue. A permanent pacemaker is then inserted to maintain a normal heart rhythmn.

    What are the side effects of the treatments?

    Beta-blockers can worsen asthma. Calcium channel blockers can cause swelling of the legs, as well as a higher risk of heart attack and congestive heart failure. Anticoagulants can cause excess bleeding.

    How is the disease monitored?

    A person with atrial fibrillation will have regular visits with the healthcare provider. The provider may order regular ECGs and blood tests to monitor treatment. Any new or worsening symptoms should be reported to the healthcare provider.


    Attribution

    Author:Bill Harrison, MD
    Date Written:
    Editor:Ballenberg, Sally, BS
    Edit Date:05/31/01
    Reviewer:Barbara Mallari, RN, BSN, PHN
    Date Reviewed:09/24/01