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Arrhythmia is an abnormal heart rhythm created by a disturbance in the heart's electrical system. During an arrhythmia, the heart may beat too fast, too slow or in an irregular pattern. Certain abnormal heart rhythms can be very dangerous, and in some cases even fatal. On the other hand, some arrhythmias are common, so-called benign arrhythmias, and aren't associated with health problems.

Years ago, the only treatments for abnormally fast heart rhythms, known as tachycardias, was medication or, in extreme cases, open heart surgery. Today, radiofrequency catheter ablation — a procedure pioneered by UCSF cardiologists — destroys the abnormal electrical pathway that causes the condition. The procedure delivers a pinpoint of heat inside the heart. Another procedure, called cryoablation, destroys the abnormal cells or electrical pathway by freezing.

Our pediatric specialists in electrophysiology are leaders in the diagnosis of these conditions and in developing treatments for all forms of abnormal heart rhythms in children.

UCSF Benioff Children's Hospitals medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your child's doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your child's provider.

Where to get care (2)

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Arrhythmia Center

Arrhythmia Center

San Francisco / Oakland

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Cardiothoracic Surgery Program

Cardiothoracic Surgery Program

San Francisco / Oakland

Our research initiatives

Awards & recognition

  • Best in Northern California for cardiology & heart surgery

  • Ranked among the nation's best in 10 specialties

Fetal surgery firsts

The first open fetal surgery in the world was performed at UCSF in the early 1980s.