In our series, 2 of the 4 patients were diagnosed as having right isomerism associated with complex cardiac anomalies.
Often, dextrocardia, complete atrioventricular septal defect, and transposed great arteries occur in both right atrial and left atrial isomerism.
It is more accurate, therefore, to speak of isomerism of the appendages.
It is the pulmonary veins, however, which most accurately reflect the presence of isomerism, and serve as discriminant markers of the right and left patterns.
Morphological considerations pertaining to recognition of atrial isomerism.
In left isomerism, the venous sinus fails to incorporate into the right-sided atrium.
Other persons may have discordance between the thoracic organs, which are usually arranged, and the abdominal organs, which are mirror-imaged, but no evidence of isomerism.
These are 'right (or left) ventricular isomerism' and 'ambiguous ventriculoarterial connections'.
