Right Juxtaposition of the Left Atrial Appendage in Complex Double Outlet Right Ventricle: Taussig-Bing Type, Associated with Overriding and Straddling of the Mitral Valve: A Morphological Study

Background: The morphologic analysis of 82 postmortem cases (DHM 1974–1992) demonstrated complete juxtaposition of the atrial appendages (JAA) in 5 cases (6.1%). Conotruncal anomalies were associated in all. Left-sided JAA of the right atrial appendage (JRAA) occurred in three cases, with solitus atria in two, and inversus atria in one. Right-sided JAA of the left atrial appendage (JLAA) was found in two cases with inversus atria and solitus atria one each. The anatomical findings of the patient with right JLAA with solitus atria(s), D-ventricular loop (D), and DORV – Taussig-Bing (S, D, D) are presented.

Method: We examined the heart specimen with emphasis on the anatomy of the atria and atrial appendages. The position of the aortic roots, infundibulum, VSD and VSD arterial root relationship, position/orientation of the infundibular septum, outflow obstruction, AV valves, ventricles, and additional associated malformations were assessed.

Results: Variations of the classical anatomic characteristics of the DORV–Taussig-Bing or new anatomical findings in our study patient included subaortic infundibular stenosis with hypoplastic aortic ostium and interrupted aortic arch (IAA) due to the rightward and subaortic malalignment of the infundibular septum. Severe overriding and straddling of the mitral valve through the infundibular septal VSD resulted in stenosis of the VSD and double inlet RV, hypoplasia of the mitral orifice/LA outlet stenosis, and small LV. Right-sided complete JLAA was associated. The small LAA was anterior and adjacent to the right of the aorta, side by side with the enlarged RAA at the right. The atrial septum secundum was deviated rightward and anteriorly. An atrial septal defect II was present.

Conclusion: Right-sided complete JLAA with rightward and anteriorly deviated septum secundum in DORV–Taussig-Bing (S, D, D) has not been described previously to our knowledge. The associated anatomical findings were essentially opposite of those found in our three patients with left-sided JRAA, and of the posterior deviation of the septum secundum reported in 2D echocardiography. The precise diagnosis of the juxtaposed atrial appendage has important implications before diagnostic or interventional and surgical procedures that involve the atrial septum such as the Cox-maze procedure in redo-Fontan patients, BAS, atrial septectomy, or Mustard-Senning procedure.

Publication History

Article published online:
28 January 2023