Related Experiment Videos
Dysplasia of the atrioventricular valves associated with conduction system anomalies
Insights
Two siblings with atrial septal defects and valve dysplasia exhibited abnormal heart electrical activity due to an accessory pathway. This suggests a congenital malformation complex affecting cardiac development.
Area of Science:
- Cardiology
- Developmental Biology
- Pathology
Background:
- Atrial septal defects and valvular dysplasia can present with complex cardiac anomalies.
- Understanding the electrophysiological consequences of congenital heart malformations is crucial for diagnosis and treatment.
Observation:
- Two siblings presented with atrial septal defects and mitral/tricuspid valve dysplasia.
- Vectorcardiography revealed abnormal ventricular activation with posterior initial electrical forces.
- Necropsy in one sibling showed incomplete leaflet differentiation resembling "mitral arcade."
Findings:
- Histological examination identified an abnormal atrioventricular node location and hypoplastic central fibrous body and membranous septum.
- An accessory nodoventricular pathway was identified, likely causing the observed abnormal ventricular activation.
- These findings suggest a congenital malformation complex involving cardiac valves and the conduction system.
Implications:
- The study highlights a potential link between valvular and conduction system anomalies in a congenital malformation complex.
- Identifying accessory pathways is critical for understanding unusual ventricular activation patterns in congenital heart disease.
- This case provides insights into the developmental origins of complex cardiac defects.
Abstract:
Clinical, vectorcardiographic, and echocardiographic data from two siblings with atrial septal defects and dysplasia of the mitral and tricuspid valves are reported. Vectorcardiograms showed that both siblings had abnormal ventricular activation with initial electrical forces directed posteriorly. One sibling died after surgery, and necropsy showed incomplete differentiation of the leaflets and tensor apparatus producing anomalies resembling "mitral arcade." Serial histological examination of the conducting tissue showed that the atrioventricular node was located on the left side of the atrial septum, that the central fibrous body and the membranous septum were hypoplastic, and that an accessory nodoventricular pathway originating in the compact node joined the left side of the ventricular septum. This accessory pathway was probably the cause of the unusual ventricular activation. Dysplasia of the mitral and tricuspid valves together with hypoplasia of the central fibrous body and the presence of accessory pathways are probably part of a malformative complex caused by incomplete differentiation of both the cardiac atrioventricular valves and the junctional area.