What is it? 

An electrocardiogram – often abbreviated, as EKG or ECG – is a test that measures the electrical activity of the heartbeat.  With each beat, an electrical impulse (or “wave”) travels through the heart.  This wave causes the muscle to squeeze and pump blood from the heart.

Why is it done? 

An EKG gives two major kinds of information.  First, by measuring time intervals on the EKG, a doctor can determine how long the electrical wave takes to pass through the heart.  Finding out how long a wave takes to travel from one part of the heart to the next shows if the electrical activity is normal or slow, fast or irregular.  Second, by measuring the amount of electrical activity passing through the heart muscle, a pediatric cardiologist may be able to find out if parts of the heart are too large or are overworked.

How is it done? 

Several sensors called electrodes will pick up the electrical activity in the heart.  Your child will lie down, and technicians will put several patches (electrodes) on the chest, arms and legs.  Usually the electrodes are soft and don’t cause any discomfort when they’re put on or taken off by the technician.  The electrodes are connected to wires called leads, which are connected to the EKG machine.  The electrical activity of the heart then is recorded on a moving strip of paper in the EKG machine.  If your child is young or anxious, you or a second technician may be needed to help provide reassurance.  During the EKG recording, your child must lie quietly for 10-20 seconds, because the electrocardiograph will detect any muscle or body movement.

Does it hurt? 

No.  There’s no pain or risk associated with having an electrocardiogram.

Is it harmful? 

No.  The machine only records the EKG.  It doesn’t send electricity into the body.