Electrocardiogram (ECG or EKG)

An electrocardiogram, also called an ECG or EKG, is a quick and painless test that measures the heart’s electrical activity.


The specialists at Norton Children’s Heart Institute, affiliated with the University of Louisville, perform EKGs at multiple locations around Louisville and Southern Indiana so you and your child can stay close to home for this routine test.


What is an EKG?

The EKG can show the heart’s rhythm, as well as the size of its chambers and their position.


Electrodes with wires are used to capture the heartbeat information. The electrodes are painless and attached to the child’s chest with sticky pads. The child’s skin should not have any baby oil or lotion on it, so the adhesive on the electrodes can stick.


Once the technician starts the EKG, the test takes about a minute. The technician or doctor may ask the child to get up and briefly exercise.


The EKG produces a graph that shows the heart’s activity in several waves. The height, length and frequency of the waves show important information, such as:


  • Heart rate: The number of waves per minute
  • Heart rhythm: The distance between the waves
  • Heart function: The shape of the waves shows electrical impulses, the heart’s size and how well the various parts of the heart work together
  • Heart damage: The consistency of the waves can show if there is damage in the heart


Types of EKGs

Different types of EKG tests can provide important information as to how a child’s heart is working.


  • Routine EKG:The most common type of EKG records the heart’s electrical activity for 10 seconds. This type of EKG evaluates the heart from 12 to 15 different directions at the same time. It can provide detailed information about the underlying heart rhythm at the time of the recording and evidence for other conditions that might affect how the heart is functioning. During this test, 12 to 15 electrode patches are placed on the chest, arms and legs. For best results, the patient should stay still while the EKG machine records the heart.
  • Holter monitor:This type of EKG uses fewer skin electrodes than the routine EKG but can record the heart rhythm for a much longer time, up to 48 hours. A Holter monitor can help find out many different things about the heart rhythm, such as:
    • Abnormalities that come and go, causing periods of irregular, fast or slow heart rhythms that might not be seen on a 10-second EKG
    • The slowest, fastest and average heart rates over the recording period
    • The patient’s underlying heart rhythm should the patient have any symptoms (such as palpitations or chest pain)


How the EKG is used

The board-certified and fellowship-trained specialists at Norton Children’s Heart Institute use EKGs to look for heart rates that are too slow or too fast, abnormal rhythms and inconsistent rhythms between the upper and lower heart chambers.


Physicians can use an EKG to diagnose four types of heart damage:


  • Ventricular hypertrophy: An abnormal thickening of the heart muscle
  • Ischemia: Blood supply that is lower than it should be
  • Cardiomyopathy: Abnormalities in the heart muscle
  • Electrolyte disorders: Changes to the heart’s electrochemicals that can be caused by medications


At Norton Children’s Heart Institute, pediatric cardiologists often combine EKGs with other tests to get a more complete picture of the cause of a child’s heart issue. For example, they may be perform an echocardiogram, which uses sound waves (ultrasound) to produce images of the heart and blood vessels’ structures on a screen. It can show the structure and function of the heart, which, combined with the EKG showing the heart’s electrical activity, gives a more complete understanding of what is going on with the heart.


Why Norton Children’s Heart Institute?

Norton Children’s Heart Institute, affiliated with the University of Louisville, is a comprehensive pediatric heart surgery, heart failure and heart transplant program serving families from Kentucky, Southern Indiana and beyond.


The goal of the full-service Norton Children’s Heart Institute is to provide care for the child and the whole family. Our specialists are prepared to repair even the most complex congenital and acquired heart conditions.


Our heart team includes:

  • Pediatric cardiothoracic surgeons
  • Pediatric transplant surgeons
  • Pediatric cardiologists
    • Fetal cardiologists
    • Adult congenital heart cardiologists
    • Heart failure/heart transplant cardiologists
    • Pediatric electrophysiologists
    • Pediatric cardiac catheterization cardiologists
  • Pediatric cardiovascular anesthesiologists
  • Pediatric intensive care physicians
  • Cardiac critical care nurses
  • Critical care pharmacists
  • Family support team
  • Child life specialists
  • Rehabilitation specialists
  • Social workers
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Norton Children’s Heart Institute

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(502) 629-2929

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