Figure 1. A: Surface electrocardiogram during atrial tachycardia. B, C: Catheter locations in right anterior oblique (RAO, B) and left anterior oblique (LAO, C) views. A 20-pole electrode catheter was placed on the tricuspid annulus (TA) with distal electrodes inside the coronary sinus, and another catheter was parallelly placed on the right atrial lateral wall (LW) close to the crista terminalis (CT). D: The schema of electrode locations. CS, coronary sinus; IVC, inferior vena cava; SVC, superior vena cava.