Divided left atrium with totally anomalous drainage of normally connected pulmonary veins

Area of Science:

• Pediatric Cardiology
• Congenital Heart Disease
• Cardiac Anatomy

Background:

• A rare congenital cardiac malformation involves pulmonary venous return to the morphologically right atrium despite normal pulmonary vein connection to the morphologically left atrium.
• This anomaly is characterized by a shelf dividing the morphologically left atrium, directing venous return to the right atrium without superior interatrial fold formation or obstruction.

Purpose of the Study:

• To discuss the interpretation of a specific congenital cardiac malformation involving an atrial septum anomaly.
• To address the question of whether the observed shelf is a deviated primary atrial septum.
• To highlight the challenges in classifying this condition within existing medical coding systems.

Main Methods:

• Review and commentary on a case study published in Cardiology in the Young.
• Analysis of the anatomical features described in the case, including atrial connections and septal morphology.
• Discussion of existing interpretations and the limitations of current diagnostic and coding frameworks.

Main Results:

• The case describes pulmonary veins connected to the morphologically left atrium, but venous return is directed to the morphologically right atrium by an atrial shelf.
• There was no evidence of superior interatrial fold formation, indicating no obstruction to systemic venous circulation.
• The precise nature of the atrial shelf (e.g., deviated primary atrial septum) remains indeterminate.

Conclusions:

• The anatomical arrangement presents a diagnostic and classification dilemma.
• Current international coding systems, including The International Paediatric and Congenital Cardiac Code (IPCCC) and ICD-11, cannot accurately code this specific congenital cardiac malformation.
• Further research and potential revisions to classification systems are needed to address such complex congenital heart defects.