Aortic aneurysms after subclavian angioplasty repair of coarctation of the aorta.

tive examination. Internal morphology of the left appendage revealed a smooth endocardium without a crista terminalis and was of the left atria1 type. The presence of left atria1 isomerism associated with a common atrium led to the diagnosis of ambiguous AV connection. Surgical correction involved rerouting the systemic venous return to the tricuspid valve. This was achieved with a “mirror image” Mustard operation. The Senning operation was not indicated because of a lack of tissue in the atria1 septum. Localization of the conductive tissue is difficult. Two AV nodes may be presente4 A similar pattern is found in AV and ventricular discordance (corrected transposition). The posterior node is hypoplastic, and the His bundle originates from the anterior node. Anderson et al5 showed that the posterior node could be connected with the His bundle. In situs inversus the posterior node is predominant, but not always so. A sling of conductive tissue could be found with fibers around the anterior and posterior margins of the ventricular septal defect. Uncertainty of the correct location of the conducting tissue explains the high frequency of complete AV dissociation following surgical repair when an AV septal defect is present.6 Suturing the interatrial baffle into place with a beating heart could help to avoid damage to the His bundle; however, in small patients, as was ours, this can be difficult to achieve.