Electrophysiologic study
All of the antiarrhythmic drugs were stopped five lifetimes before the study. Five electro catheters were inserted into the heart, three via the left femoral vein and two via the right femoral vein. Three quadripolar catheters from the left femoral vein were placed in RA-RV-HIS location, and one decapolar catheter from the right femoral vein was placed into the CS. An ablation catheter was inserted into the right atrium to map and ablate the slow pathway.