Corrected transposition of the great arteries involving situs inversus {I, D, D} and mild pulmonary stenosis: conduction system identified during preoperative investigations for a double-switch operation.

The atrioventricular (AV) conduction system in corrected transposition of the great arteries (cTGA) involving situs inversus remains unclear. A case of cTGA involving situs inversus, mild pulmonary stenosis, and ventricular septal defect (VSD) is reported. An electrophysiologic study using the CARTO system and angiography was performed to identify the AV conduction system before a double-switch operation with VSD enlargement. The His bundle was located at the anteroseptum of the left-sided RA. It descended along the posteroinferior margin of the VSD with cTGA involving situs inversus and a normal-sized pulmonary trunk. No AV block occurred after surgery. The combination of the CARTO system and angiography could be useful for identifying the conduction system.