First-Degree AV Block in Children

Your child’s heart has a natural electrical system that tells it when to beat. Part of this system is called the AV node, or atrioventricular node. The AV node helps send the signal from the top part of the heart (the atria) to the bottom part (the ventricles), so the heart can beat in a steady, healthy rhythm. 

What is a first-degree AV block?

First-degree AV block means that the signal takes a little longer than normal to travel through the AV node. It’s like a small delay in the heart’s electrical message. This is usually found during an electrocardiogram (ECG), a test that records how the heart’s electrical system is working. Most of the time, it’s found by accident when a child is getting checked for something else.

Why does it happen? 

In many healthy kids, this kind of delay can be totally normal. It can happen when the vagus nerve (a major nerve that helps the body relax) is more active, like during sleep or calm times. The vagus nerve can slow the heart’s signal just a little. This isn’t dangerous and doesn’t mean anything is wrong.

Sometimes, a first-degree AV block can be an early sign that the heart’s electrical system is slowing down over time. In those cases, your child’s doctor may want to watch things more closely.

Does it cause symptoms?

First-degree AV blocks don’t cause any symptoms. Kids feel normal and healthy. Most children with a first-degree AV block won’t need any treatment.

How do we monitor it?

Your child’s doctor may order tests to see if the delay changes with activity or rest.

• ECG – A short test that shows the heart’s rhythm.
• Holter monitor – A 24-hour test that watches the heart over a full day.
• Exercise (stress) test – A test to see how the heart reacts during activity.

What about treatment?

Usually, no treatment is needed. If your child’s heart rhythm is normal except for this small delay, they may not need follow-up. If there are signs of other changes in the heart’s rhythm, the cardiologist may want to check in from time to time to make sure everything is still working well.

In summary:

• First-degree AV block is a mild delay in the heart’s electrical signal.
• It’s often normal, especially in healthy kids, during sleep or rest.
• It doesn’t cause symptoms.
• Most kids don’t need any treatment.
• Your child’s doctor may check the heart rhythm occasionally just to be safe.