Question:medium
What is the most common cause of complete heart block (acquired complete AV block) in infants and children?
What is the most common cause of complete heart block (acquired complete AV block) in infants and children?
Show Hint
Think of trauma to the AV node during cardiac repair in children.
Updated On: Jun 24, 2026
- SLE
- Surgery for congenital heart disease
- Viral myocarditis
- Rheumatic fever
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: When a child develops a permanent acquired third-degree AV block, the leading explanation is injury sustained while correcting a congenital cardiac defect surgically. Therefore option b is correct.
Step 2: During repair the AV node or its surrounding conduction pathway can be damaged by bleeding, reduced blood supply, tissue death, swelling, or mechanical cutting, any of which interrupts the normal electrical relay between atria and ventricles.
Step 3: Ranking second is congenital heart disease that comes packaged with congenital complete heart block, a distinct entity from the post-operative form.
Step 4: Inflammatory causes such as viral myocarditis, acute rheumatic fever, Lyme disease and drug toxicity (digitalis) can block AV conduction too, yet they tend to resolve and occur less often, so none outranks surgical trauma.
\[\boxed{\text{Surgery for congenital heart disease}}\]
Step 2: During repair the AV node or its surrounding conduction pathway can be damaged by bleeding, reduced blood supply, tissue death, swelling, or mechanical cutting, any of which interrupts the normal electrical relay between atria and ventricles.
Step 3: Ranking second is congenital heart disease that comes packaged with congenital complete heart block, a distinct entity from the post-operative form.
Step 4: Inflammatory causes such as viral myocarditis, acute rheumatic fever, Lyme disease and drug toxicity (digitalis) can block AV conduction too, yet they tend to resolve and occur less often, so none outranks surgical trauma.
\[\boxed{\text{Surgery for congenital heart disease}}\]
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