Open‐Window Mapping for Accessory Pathway Ablation: Influence of Catheter Design on Mapping Performance

Figures

• 

  FIGURE 1. Representative case of open‐window mapping using an 8‐spline high‐density catheter in a patient with a concealed accessory pathway. (A–D) Open‐window mapping (OWM) performed during left ventricular pacing identified a posterolateral accessory pathway (AP) along the mitral annulus. The AP conduction gap was visualized by adjusting the lower extended early‐meets‐late (EEML) threshold to 19% to align with the propagation map (Supplementary Video 1). (E) Local electrograms recorded from the distal bipoles of the ablation catheter positioned within the EEML gap demonstrated the earliest atrial activation during ventricular pacing. (F) The first radiofrequency (RF) application at this site resulted in termination of atrioventricular reentrant tachycardia (AVRT) within 1 s. Small discontinuous white lines occasionally observed within the EEML gap represent either incomplete conduction block or threshold‐dependent segmentation artifacts and do not indicate separate APs. ABL, ablation catheter; AVRT, atrioventricular reentrant tachycardia; CS, coronary sinus; dist, distal; LV, left ventricle; prox, proximal; RA, right atrium; RF, radiofrequency.

• 

  FIGURE 2. Representative case of open‐window mapping using an 8‐spline high‐density catheter (Octaray) in a patient with a concealed accessory pathway located at the lateral tricuspid annulus. (A–D) Open‐window mapping performed during right ventricular pacing identified a lateral accessory pathway (AP) along the tricuspid annulus. The AP conduction gap was visualized by adjusting the lower extended early‐meets‐late (EEML) threshold to 22% to align with the propagation map, which delineates oblique ventriculoatrial conduction across the tricuspid annulus (Supplementary Video 2). (E) Local electrograms recorded from the distal bipoles of the ablation catheter positioned within the EEML gap demonstrated the earliest atrial activation during ventricular pacing. (F) Following the first radiofrequency (RF) application, separation of previously fused atrial and ventricular components was observed at the distal bipoles, indicating successful elimination of AP conduction within 2 s.

• 

  FIGURE 3. Representative case of open‐window mapping using an 8‐spline high‐density catheter (Octaray) in a patient with a concealed accessory pathway located at the septal tricuspid annulus. (A–D) Open‐window mapping performed during atrioventricular reentrant tachycardia identified an inferoseptal accessory pathway (AP) along the tricuspid annulus. The AP conduction gap was visualized by adjusting the lower extended early‐meets‐late (EEML) threshold to 22% to align with the propagation map (Supplementary Video 3). (E) Local electrograms recorded from the distal bipoles of the ablation catheter positioned within the EEML gap demonstrated the earliest atrial activation during tachycardia. (F) The first radiofrequency (RF) application at this site resulted in immediate elimination of AP conduction within 2 s.

• 

  FIGURE 4. Representative comparison of open‐window mapping between 8‐spline and 5‐spline catheter designs. Representative examples of mapping density obtained using the 8‐spline catheter (Octaray) (A) and the 5‐spline catheter (Pentaray) (B) under comparable mapping durations. The 8‐spline catheter demonstrates higher point density and more detailed visualization of the extended early‐meets‐late (EEML) gap, with a narrower apparent accessory pathway (AP) width compared with the 5‐spline catheter.