High-risk accessory pathway associated with a rare right atrial diverticulum: a case report

Figure 1. The baseline twelve-lead electrocardiogram reveals the presence of a right posteroseptal accessory pathway. AP, accessory pathway.

Figure 2. Pre-procedural and procedural characteristics of the ablation. (A) Selective coronary sinus venogram reveals a giant right atrial diverticulum situated immediately proximal to the coronary sinus ostium (arrow). (B–C) High-resolution 3D electro-anatomical mapping in left-lateral (B) and left anterior oblique (C) views precisely confirms the location of the diverticulum (arrows). It is situated between the tricuspid valve and the coronary sinus ostium, extending posteriorly and inferiorly, away from His-detected potentials (marked in yellow) and the superior vena cava. (D) The accessory pathway potential (red arrow) with unipolar QS signal (blue arrow) is identified at the tip of the diverticulum and targeted for radiofrequency ablation. (E) Successful radiofrequency ablation results in the disappearance of the accessory pathway potentials (red arrow), with confirmation of pathway elimination (blue arrow). TV, tricuspid valve; CS, coronary sinus; SVC, superior vena cava.

Figure 3. The post-ablation twelve-lead electrocardiogram demonstrated the resolution of pre-excitation, accompanied by T-wave inversions in the inferior leads, consistent with electrical memory.

Figure 4. Post-procedural cardiac magnetic resonance. Sagittal T2-TRUFI sequence confirms the localization of the diverticulum within the right atrial wall and provides precise size quantification, measuring approximately 20 × 16 mm.

Figure 5. Timeline of events from the initial identification of the accessory pathway on 12-lead electrocardiogram to the ablation procedure, including the discovery of a right atrial diverticulum, and the one-year follow-up. AP, accessory pathway.