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Morphology of the posterior junctional area in atrioventricular septal defects
1Department of Paediatrics, National Heart and Lung Institute, London, United Kingdom.
Insights
In hearts with atrioventricular septal defects, the coronary sinus location varies but the atrioventricular conduction axis remains consistently positioned. This study clarifies anatomical relationships for surgical planning.
Area of Science:
- Cardiovascular Anatomy
- Congenital Heart Disease Research
- Cardiac Electrophysiology
Background:
- Atrioventricular septal defects (AVSD) present complex cardiac morphology.
- Understanding the spatial relationship between the coronary sinus and the atrioventricular conduction axis is crucial for surgical interventions in AVSD patients.
Observation:
- The study examined 40 hearts with AVSD, noting variations in coronary sinus drainage and termination.
- In 5 hearts, the coronary sinus received drainage from a persistent left superior caval vein.
- Four hearts showed the coronary sinus terminating abnormally in the left atrium.
Findings:
- Despite variations in coronary sinus anatomy, including drainage anomalies and atrial termination, the atrioventricular conduction axis consistently occupied its typical position.
- The conduction axis was located at the junction of the ventricular septum and the atrioventricular junction, irrespective of coronary sinus disposition.
- Septal malalignment relative to the crux cordis did not alter the fundamental location of the conduction axis.
Implications:
- The findings reinforce the principle that the atrioventricular node and penetrating bundle's location are predictable in AVSD.
- This anatomical understanding is vital for minimizing risks of heart block during surgical repair of atrioventricular septal defects.
- Accurate localization of the conduction axis aids in improving surgical outcomes and patient safety in congenital heart defect management.
Abstract:
The location and size of the coronary sinus in hearts with atrioventricular septal defect were investigated in relation to the known disposition of the atrioventricular conduction axis. We examined the morphology in 40 hearts and supplemented this series with two other hearts that had been serially sectioned previously. The coronary sinus received drainage from a persistent left superior caval vein in 5 hearts. Six cases of 40 had malalignment of the septal structures relative to the crux of the heart. In these, the conduction axis was anticipated to course in the position where the inlet ventricular septum met the atrioventricular junction. The coronary sinus terminated in the left atrium in 4 hearts: 2 in the morphological series and 2 that were sectioned for histological studies. The sectioned hearts showed the atrioventricular conduction axis in the usual position for the defect, unrelated to the coronary sinus. The principle that the node and penetrating bundle are located at the intersection of the ventricular septum with the atrioventricular junction holds good despite the variability of the coronary sinus.