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 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.
- Dizziness or light-headedness
- Fainting (syncope)
- Chest pain
- Shortness of breath
- 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 out for signs, like:
- Child has trouble keeping up with other children when playing
- Child has “spells” during play and needs to sit down and rest
If your child has any of these symptoms, do not assume it is due to heart block. These symptoms may be caused by other, less serious health conditions.
The doctor will ask about your child’s symptoms and medical history. A physical exam will be done.
shows the heart's electrical activity. The doctor will be able to see a heart block with this test.
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.
If your child is diagnosed with heart block, follow the doctor's instructions.
Unfortunately, there is no way to prevent heart block in your child.
First-degree AV nodal block. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed/what.php. Updated June 14, 2013. Accessed June 20, 2013.
Heart block. Heart Rhythm Society website. Available at:
http://www.hrsonline.org/Patient-Resources/Heart-Diseases-Disorders/Heart-Block. Accessed on June 20, 2013.
Second degree atrioventricular nodal block (non-Wenckebach). EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed/what.php. Updated April 18, 2013. Accessed June 20, 2013.
Third degree atrioventricular nodal block. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed/what.php. Updated January 21, 2011. Accessed June 20, 2013.
University of California San Francisco. Heart block. UCSF Benioff Childrens’ Hospital website. Available at:
http://www.ucsfchildrenshospital.org/conditions/heart_block/. Accessed on June 20, 2013.
What is heart block? National Heart, Lung and Blood Institute website. Available at:
http://www.nhlbi.nih.gov/health/health-topics/topics/hb/. Accessed on June 20, 2013.
Last reviewed December 2013 by Kari Kassir, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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