A 49-year-old woman with dextrocardia and situs inversus underwent catheter ablation of paroxysmal atrial fibrillation. A contrast injection into the left atrium revealed that the left atrial appendage (LAA) was adjacent to the right-sided (anatomic left) superior pulmonary vein (PV). After successful isolation of that PV, LAA potentials were recorded from several electrode pairs of a circular PV mapping catheter. LAA may cause similar difficulties during PVI of the right-sided superior PV in a dextrocardia patient, as during PVI of the left superior PV in a normal heart. © The Author 2008.