(Atrioventricular [AV] Block—Child)
The heart has two upper chambers called atria and two lower chambers called ventricles. Electrical signals move through special nerve bundles to the atria then to the ventricle. When the electrical signals pass through as expected the heart pumps rhythmically.
Heart block occurs when the electrical signals do not travel normally through the heart. The heart can still pump blood, but it beats much slower and less efficiently than normal.
There are three types of heart block, ranging from mild to serious:
- First-degree heart block—mildest form of heart block. Electrical signals reach all parts of the heart but move more slowly than normal. There are usually no symptoms, and heartbeat is normal.
- Second-degree heart block—some of the electrical signals are not reaching the ventricles. This means that sometimes the ventricles do not pump when they should.
- Third-degree, or complete, heart block—most serious type of heart block. No electrical signals are able to reach the ventricles. Cells in the ventricles act as a back up and create their own electrical signals. This allows the ventricles to keep pumping, but it is slower and out of rhythm with the rest of the heart. .
|Anatomy of the Heart
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The causes of heart block in children may include:
- Heart defect caused by genetics
- Certain medications
- Damage from surgery
Infections such as
in the mother
- Electrolyte abnormalities
- Autoimmune disorder
Factors that may increase your child's chance of heart block include:
- Previous heart problems like heart failure or heart attack
- Heart valve problems
- Certain medications
- Exposure to toxic substances
Your child may not have any symptoms at all. If your child has any of the following, see the doctor.
- Chest pain
- Shortness of breath
- Rapid or slow heart beat
- Weakness or fatigue
Be aware that your child may feel these symptoms, but may not be able to tell you or know how to describe them. Watch for signs, like:
- Trouble keeping up with other children when playing
- Needing to take resting breaks from playing
You will be asked about your child’s symptoms and medical history. A physical exam will be done.
The electrical activity of your child's heart may need to be tested. This can be done with an
The course of treatment will depend on the type of heart block. Generally, treatment is not needed for first-degree heart block.
may be needed for some cases of second-degree heart block and all cases of third-degree heart block. The pacemaker will send regular electrical signals to the heart. It will keep the heart beating in a more efficient rhythm.
Unfortunately, there is no way to prevent heart block in your child.
CardioSource—American College of Cardiology
Heart Rhythm Society
Canadian Cardiovascular Society
Heart and Stroke Foundation of Canada
Atrioventricular (AV) conduction. EBSCO DynaMed Plus website. Available at:
http://www.dynamed.com/topics/dmp~AN~T907302/Atrioventricular-AV-conduction-disorders. Updated September 9, 2016. Accessed September 29, 2016.
Heart block. Heart Rhythm Society website. Available at:
http://www.hrsonline.org/Patient-Resources/Heart-Diseases-Disorders/Heart-Block. Accessed November 3, 2014.
Second degree atrioventricular nodal block (non-Wenckebach). EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed. Updated April 18, 2013. Accessed November 3, 2014.
University of California San Francisco. Heart block. UCSF Benioff Childrens’ Hospital website. Available at:
http://www.ucsfchildrenshospital.org/conditions/heart%5Fblock/. Accessed November 3, 2014.
What is heart block? National Heart, Lung and Blood Institute website. Available at:
http://www.nhlbi.nih.gov/health/health-topics/topics/hb/. Updated July 9, 2012. Accessed November 3, 2014.