Clinical Characteristics and Timing of Accessory Pathway Reconduction During Catheter Ablation of Accessory Pathways

Figures

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  FIGURE 1. Representative case of a broad accessory pathway. (A) Baseline 12‐lead ECG exhibited no delta waves, consistent with a concealed AP. (B) During RV apex pacing, the earliest atrial activation was broadly observed between the 4 and 5 o'clock positions on the MVA. (C) Left panel shows intracardiac electrograms (IECG) during baseline RV pacing at a cycle length of 500 msec. The earliest atrial activation was observed at CS 2–3, corresponding to the 4–5 o'clock position on the MVA. The stimulus‐to‐VA interval was 129 msec, consistent with a concealed AP. Right panel shows a fluoroscopic image of the ablation catheter positioned at the initial ablation site, indicated by the red arrow. (D) Left panel shows an IECG recorded after multiple RF applications during RV pacing at a cycle length of 500 msec. The earliest atrial activation was still observed at CS 2–3, similar to pre‐ablation findings; however, the stimulus‐to‐VA interval was prolonged to 140 msec compared to baseline. Right panel shows a fluoroscopic image of the ablation catheter positioned at the final ablation site, indicated by the red dotted arrow. CS, coronary sinus; dis, distal; His, his bundle region; HRA, high right…

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  FIGURE 2. Representative case of multiple accessory pathways. (A) The baseline 12‐lead ECG showed no delta waves, consistent with a concealed AP. (B) A dual‐chamber activation map obtained during AVRT. The red arrow indicates the successful ablation site at the 7 o'clock position on the MVA, along with the corresponding fluoroscopic image showing the catheter position at the time of AP interruption. (C) A dual‐chamber map obtained during RV pacing, demonstrating a second AP at the 3 o'clock position on the MVA. The red dotted arrow marks the successful ablation site for this AP, along with the fluoroscopic image showing the catheter position at the time of pathway elimination. (D) IECG during AVRT, in which the earliest atrial activation was observed at the 7 o'clock position on the MVA. Although RF energy was delivered to this site, the tachycardia did not terminate; however, the site of earliest atrial activation shifted from MVA 7 o'clock (*) to MVA 3 o'clock (⁑). Abbreviations are as in Figure 1.

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  FIGURE 3. Representative case of an oblique accessory pathway. (A) The baseline 12‐lead ECG demonstrated manifest preexcitation, suggesting a septal AP. (B) The red arrow indicates the site of the earliest ventricular activation and its corresponding local electrogram during antegrade AP activation mapping. The red dotted arrow denotes the site of the earliest atrial activation during retrograde AP mapping as well as the ablation point. The linear distance between these two sites was 12 mm, and the curved distance measured on the 3D mapping surface was 12.4 mm. (C) IECGs recorded during ablation are shown. RF energy was delivered during RV pacing, resulting in successful interruption of the AP conduction within 1 s. (D) Fluoroscopic images demonstrate the catheter position at the site of successful ablation. Abbreviations are as in Figures 1 and 2.

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  FIGURE 4. Representative case requiring a complex ablation approach. (A) The baseline 12‐lead ECG demonstrated manifest preexcitation, suggesting a right AP. (B) Ablation tags are displayed on the 3D mapping system. The red dotted arrows indicate the ablation tags created via the transfemoral approach, during which AP reconduction was observed during the procedure. In contrast, the red arrow shows the ablation tag delivered from the subvalvular aspect via the transjugular approach, which successfully achieved complete interruption of AP conduction. (C) IECGs recorded during successful ablation are shown. Radiofrequency energy was delivered during high right atrium pacing, resulting in successful interruption of AP conduction within 1.5 s. Abbreviations are as in Figures 1 and 2.

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  FIGURE 5. Temporal distribution of accessory pathway (AP) reconduction during the 30 min waiting period after apparent elimination of AP conduction. (A) Kaplan–Meier–style curve illustrating freedom from AP reconduction. Time was measured from the apparent elimination of AP conduction to the first detection of reconduction during the waiting period. (B) Histogram showing the distribution of the time to AP reconduction. Reconduction events occurred throughout the 30 min waiting period, with the highest frequency between 20 and 24 min.