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 at rial appendages in association with multiple spleens and complete heart blo ck. In both of these, the venous connections were normal. In one case the a rrangement of the bronchial tree and the lungs was normal, the liver was le ft-sided, and the stomach was right-sided. In the other case, there was lef t isomeric broncho-pulmonary morphology, and both liver and stomach were ri ght-sided. These unusual combinations show the need for full description of the morphology of other organs, and the venoatrial connections, in cases w ith isomeric arrangement of the atrial appendages. They also demonstrate th at connection of the inferior caval vein cannot be taken as a reliable mark er of an atrium having a morphologically right appendage.