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[Congenital atrio-ventricular blocks in infants. Histological study of the conduction system]
Insights
Congenital heart block in infants is rare. This study reveals that the cause is often an interruption or absence of the His bundle, not other heart abnormalities.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease
- Electrophysiology
Background:
- Complete congenital atrio-ventricular block is a rare and serious condition in infants.
- Understanding the underlying causes is crucial for diagnosis and management.
Observation:
- Three infant cases of complete congenital atrio-ventricular block were studied.
- One case had a familial component with a macroscopically normal heart.
- Two cases presented with associated cardiac anomalies (aortic arch discontinuity, situs inversus with PDA and VSD).
Findings:
- Pathological examination revealed interruption or absence of the penetrating portion of the bundle of His as the cause of the block.
- In one case, agenesis of the atrio-ventricular node was also noted.
- Associated cardiac abnormalities were not the primary cause of the conductive defect.
Implications:
- This study highlights the critical role of the His bundle in congenital atrio-ventricular block.
- Accurate pathological assessment is vital for identifying the specific etiology.
- Further research into the genetic and developmental factors is warranted.
Abstract:
The authors present a clinico-pathological study of three cases of complete congenital atrio-ventricular block in the infant. In one case the disorder was familial, and the heart was macroscopically normal. In the other two cases, the associated abnormalities (complete discontinuity of the aortic arch in one, and situs inversus with a patent ductus and high VSD in the other) were not responsible for the conductive defect. This was explained after study of serial sections of the inter-atrio-ventricular septum; these showed an interuption or absence of the penetrating portion of the bundle of His associated, in one case, with agenesis of the atrio-ventricular node.