Isomeric arrangement of the left atrial appendages and visceral heterotaxy: two atypical cases.

We present two cases in which there was isomeric arrangement of the left atrial appendages in association with multiple spleens and complete heart block. In both of these, the venous connections were normal. In one case the arrangement of the bronchial tree and the lungs was normal, the liver was left-sided, and the stomach was right-sided. In the other case, there was left isomeric broncho-pulmonary morphology, and both liver and stomach were right-sided. These unusual combinations show the need for full description of the morphology of other organs, and the venoatrial connections, in cases with isomeric arrangement of the atrial appendages. They also demonstrate that connection of the inferior caval vein cannot be taken as a reliable marker of an atrium having a morphologically right appendage.