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What is electrocardiography?

Your child’s heart is a large muscle that pumps blood through their body. Their heart works because electrical current moves through the heart to make it beat. An electrocardiogram [ih-LEK-trow-KAR-dee-oh-GRAM] test measures this current to see how the heart is working.

How does electrocardiography work?

To pump blood to the body, the heart must fill with blood and then squeeze it out. The electrical system of the heart tells the heart when to beat by sending a very small electrical current through the

muscle. If there is no electrical current, the heart will not beat.

An ECG measures those electric currents. This test helps the doctor find out if your child has an irregular heartbeat, if the heart is bigger than normal, or if the heart’s electrical system is working correctly.

The technician will put leads (sticky patches) on your child’s chest that sense the electrical current in the heart. The technician will use several leads to test the heart from different angles.

Sensitive machines detect the electrical current on the skin’s surface as the current passes through your child’s heart. An ECG puts out a paper printout that shows how electricity moves through your child’s heart. A cardiologist [kahr-dee-OL-uh-jist], a doctor who specializes in the heart and blood system, will read and interpret the results.

What are the risks and/or side effects?

The main risk to the test is a skin allergy to the adhesive used to attach the leads. This may result in temporary redness and skin irritation where the leads are placed.

The ECG machine also gives off a tiny amount of radiation, which can slightly increase your lifetime cancer risk. (For more information, see Intermountain Healthcare’s Guide to Understanding Radiation).

What are the benefits?

An electrocardiogram is a simple, easy test that can measure the health of your child’s heart. An ECG checks for:

  • Problems with your child’s heart rate
  • Problems with your child’s heart rhythm
  • Damaged heart muscle
  • Increased thickness in the heart muscle
  • Lack of good blood flow to the heart muscle

How do I prepare?

Your child does not need to do anything to prepare for an electrocardiogram. However, to help the technician place the leads correctly, do not put baby oil or lotion on your child before the test. These products can stop the electrodes from sticking to your child’s skin.

How is it done or administered?

You and your child will go into a private room with the ECG machine. You will remove your child’s shirt so that painless, sticky pads can be placed on their chest. These pads are then connected to wires that run to the ECG machine.

The technician will push the record button on the machine, and the machine will print a piece of paper with spiky ECG lines. Then the sticky patches will be removed, and your child may get dressed. The electrical recording takes 1 minute. The entire procedure takes less than 10 minutes.

During the exam, your child will need to hold still. They may sit on your lap to be more comfortable. The test is not painful.

When will I know the results?

After the test, the ECG results will be given to your child’s doctor. Your child’s doctor or a heart doctor (cardiologist) will review and interpret the ECG tracing. You will get the results at a follow-up appointment or sometimes during the same appointment.

What are follow-up requirements and options?

If the ECG shows there might be a problem with your child’s heart, they might need to have other tests or procedures. Your child’s doctor will tell you if this is the case.