Figure 3. A: Activation during entrainment pacing from the lateral tricuspid annulus (TA). Pacing (star) directly captured the anterior circuit (arrow a) on the TA and the posterior circuit (arrow b) around the block line on the posterior wall later. B: Activation during entrainment pacing from the proximal coronary sinus (CS). Pacing captured the anterior circuit (arrow c) and posterior circuit (arrow d) simultaneously. The letters on the arrows correspond to those in Fig. 2. IVC, inferior vena cava; SVC, superior vena cava.