Figure 2.

A: Fluoroscopic image (anterior-posterior view) of the coronary sinus (CS) and branch of the vein of Marshall (VOM), and the intracardiac electrocardiogram (ICE) recordings. By a contrast injection from the tip of the irrigated ablation catheter (ABL), the VOM was identified. Ao = electrode catheter as a reference in the aortic cusp; Eso = thermometer in the esophagus; LAA = ring catheter in the left atrial appendage; RV = right ventricle. B, C, D: The intracardiac electrograms for measuring the post pacing interval (PPI) at CS proximal (B) and left atrial (LA) ridge (C) and during the termination with ablation (D). The PPI at both sites (B and C) matched the tachycardia cycle length. D: Before the ablation the earliest activation site was at the CS mid (red arrow). After the atrial tachycardia terminated, the sequence of the CS potentials changed from proximal to distal.