A Case of Radiofrequency Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia Using Transseptal Approach, Guided by Electro-Anatomical Mapping System

A 65 year-old female was admitted to our hospital because of syncope. She has been previously diagnosed with dilated cardiomyopathy. Twelve-lead electrocardiogram (ECG) presented narrow QRS tachycardia. Electrophysiological study and radiofrequency catheter ablation was performed. Under isoproterenol infusion, supraventricular tachycardia (SVT) was easily induced followed by critical AH interval. The mechanism of SVT was diagnosed with slow-fast atrioventricular nodal reentrant tachycardia (AVNRT). We tried slow-pathway ablation from venous approach targeted at the triangle of Koch using electrogram guide and anatomical approach. Slow-pathway conduction was not eliminated, however, and SVT still could be easily induced. Therefore we delivered radiofrequency (RF) from the left atrial (LA) septum by transseptal approach using an electro-anatomical mapping (EAM) system. After RF application at mid-septum from the LA, the slow-pathway conduction was modified and SVT could not be induced.