A 70-year-old woman with situs inversus totalis underwent catheter ablation for atrial fibrillation and atrial flutter. Although her morphologic left atrium (LA) was enlarged, we performed cryoballoon ablation and liner radiofrequency ablation of the cava-tricuspid isthmus without mapping atrial arrhythmias. However, a different form of atrial tachycardia (AT) recurred. We performed catheter ablation a second time using a three-dimensional electroanatomic mapping system. AT was not terminated by the liner ablation at the roof of morphologic LA and mitral isthmus but sustained by changing the atrial activation sequence and cycle length. Multipolar mapping catheter revealed that fractionated low-amplitude potentials were densely located in a limited area of the anterior morphologic LA, and an activation map demonstrated the presence of small-circuit reentry with an extremely slow conduction at the anterior morphologic LA. A single energy application targeting the fragmented potentials successfully terminated the AT. We successfully treated multiple ATs with a complex anatomy using a three-dimensional electroanatomic mapping system.
Keywords: cryoballoon ablation; multiple atrial tachycardia; situs inversus totalis; small closely spaced electrodes; three-dimensional electroanatomic mapping system.