Fig. 3.

Catheter mapping for radiofrequency catheter ablation and a 12-lead ECG while delivering radiofrequency energy. (A) Activation mapping for spontaneous trigger PVBs showed the earliest ventricular activation, which included presystolic Purkinje potentials (PSPp) 32 ms prior to the QRS onset. Paced mapping at the right ventricular inferior septum, which was the EAS, showed a QRS morphology nearly identical to that of spontaneous PVBs. (B) A representation of an ablation catheter placed on the EAS and other catheters or leads. (C) A representative intracardiac electrocardiogram recording that recorded Purkinje potentials (Pp, black arrows) at the EAS during sinus rhythm. His potentials (Hp, red arrows) were also recorded at the proximal His bundle (HBp) catheter. PSPp=presystolic Purkinje potential, HRA=high right atrium, HBp=proximal His bundle, HBd=distal His bundle, CSp=proximal coronary sinus, CSd=distal coronary sinus, RVa=right ventricular apex, ABL=ablation catheter, LAO=left anterior oblique, RAO=right anterior oblique, Pp=Purkinje potential, and Hp=His potential.