Atrial Fibrillation

Atrial fibrillation is a type of arrhythmia in which the two upper chambers of the heart, called the atria, quiver instead of beating effectively. This may result in rapid and irregular impulses in the atrium — as fast as 300 per minute — which typically causes a faster than normal and irregular ventricular rhythm.

The "normal" number of heartbeats per minute, called pulse rate, varies with age. The heart beats about 140 times a minute in a newborn, compared to 70 times a minute in an older child at rest. Heart rate is not constant and changes in response to many factors, such as activity, fever and fear. In atrial fibrillation the heart cannot fill completely with blood, preventing the body from receiving the blood volume it needs to function properly.

Atrial fibrillation may cause the following symptoms:

  • Chest pressure or pain
  • Fainting, also known as syncope, or near-syncope
  • Fatigue
  • Lightheadedness or dizziness
  • Palpitations, which can be skipping, fluttering or pounding in the chest
  • Shortness of breath

It is important to note that some children may not know how to describe what they are feeling during a period of atrial fibrillation. They may have trouble keeping up with other children or realize they are having "spells" and want to sit down and rest. Sometimes, a child does not experience any symptoms at all.

Atrial fibrillation often occurs spontaneously and with unpredictable timing. Therefore, in many cases, the condition requires specialized tests to acquire an accurate diagnosis. If your doctor suspects that your child has an arrhythmia, such as atrial fibrillation, he or she will order one or more of the following diagnostic tests to determine the source of your child's symptoms.

  • Electrocardiogram (ECG or EKG) — An electrocardiogram records the heart's electrical activity. Small patches called electrodes are placed on your child's chest, arms and legs, and are connected by wires to the ECG machine. The electrical impulses of your child's heart are translated into a graph or chart, enabling doctors to determine the pattern of electrical current flow in the heart and to diagnose arrhythmias.
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Treatment for your child's atrial fibrillation will depend on the type and severity of your child's condition and the results of their various diagnostic tests, such as the electrophysiology (EP) study. You and your doctor will decide which treatment is right for your child.

The following treatments may be considered:


Certain anti-arrhythmic drugs change the electrical signals in the heart and help prevent irregular or rapid heart rhythms from occurring. Medication may be used to convert atrial fibrillation to a normal rhythm, slow down the heart rate or prevent recurrences. If medication is ineffective, the doctor may try to stop the atrial fibrillation with pacing or with an electrical cardioversion.

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Reviewed by health care specialists at UCSF Benioff Children's Hospital.

Related Information

UCSF Clinics & Centers

Heart Center

Arrhythmia Center
1825 Fourth St., Sixth Floor
San Francisco, CA 94158
Phone: (415) 514-2783
Fax: (415) 353-4144
Appointment information

Pediatric Heart Center Clinic at Mission Bay
1825 Fourth St., Sixth Floor
San Francisco, CA 94158
Phone: (415) 353-2008
Fax: (415) 353-4144
Appointment information

Cardiac Intensive Care Unit
1975 Fourth St., Fourth Floor
San Francisco, CA 94158
Phone: (415) 353-1955
Fax: (415) 353-9144