An irregular heartbeat is an arrhythmia. The most common irregularity occurs during breathing. When a child breathes in, the heart rate normally speeds up for a few beats. When the child breathes out, it slows down again. This variation with breathing is called sinus arrhythmia. It's completely normal.

Sometimes a doctor may find other kinds of arrhythmia. Then he or she may want to perform some tests. The doctor may also recommend that a pediatric cardiologist (a doctor specializing in children's heart problems) examine your child.

Knowing your child's history
Arrhythmias (also called dysrhythmias) may occur at any age. Many times they have no symptoms. Often parents and children never suspect an arrhythmia and are surprised when a doctor finds one during a routine physical exam. Rhythm abnormalities are usually evaluated much like other health problems. Your child's history — or what you and your child report about the problem — is very important. You may be asked questions like:

• Is your child aware of unusual heartbeats?
• Does anything bring on the arrhythmia? Is there anything your child or the family can do to make it stop?
• If it's a fast rate, how fast?
• Does your child feel weak, lightheaded or dizzy?
• Has your child ever fainted?

Some medicines may make arrhythmias worse. Be sure to tell your doctor about all the prescribed and over-the-counter medications that your child takes. If your child has an arrhythmia, discuss this with the doctor and ask what to look for.

This content is reviewed regularly. Last updated 01/15/09.