Juxtaposition of the Atrial Appendages: A Large Echocardiographic Series.

Juxtaposition of the atrial appendages is known to occur in specific congenital heart lesions. Recognition of these variants is critical in balloon atrial septostomy and atrial switch operations. There remains little clinical data on the prevalence and associations of these lesions. This is the largest echocardiographic study of juxtaposition of the atrial appendages. This is a retrospective study using the Mt. Sinai echocardiogram database (EchoLAN), which contains echocardiogram reports performed or reviewed at Mt. Sinai Hospital (New York, NY) between 1992 and 2019. Each report was reviewed for associated intracardiac and extracardiac anomalies and the prevalence of juxtaposed atrial appendage among specific diagnosis, including tricuspid atresia, transposition of the great arteries, and double outlet right ventricle, was calculated. Descriptive and analytical statistics were performed as applicable, including Fisher's exact test, with p value < 0.05 considered statistically significant. Forty-nine patients had juxtaposed atrial appendages (1.2/1000 patients): Thirty-eight had LJRAA (0.9 per 1000 patients) and eleven had RJLAA (0.3 per 1000 patients). LJRAA was seen in 22% of tricuspid atresia, 6% of d-TGA, 1% of l-TGA, and 5% of DORV. RJLAA was seen in 2% of DORV, and none of the other lesions. Of associated lesions, dextrocardia, mesocardia, transposition, tricuspid atresia, double inlet left ventricle, and pulmonary valve stenosis were more likely to be present in LJRAA, while bicuspid aortic valve and left ventricular hypoplasia were more likely to be present in RJLAA. This study reaffirms our understanding of juxtaposition of the atrial appendages, its prevalence, and clinical importance.