Radiofrequency catheter ablation for Wolff-Parkinson-White syndrome associated with a coronary sinus diverticulum

The case of a patient with Wolff-Parkinson-White syndrome undergoing attempted radiofrequency catheter ablation of a left posterior paraseptal accessory pathway is described. Coronary sinus venography revealed the presence of a large diverticulum attaching near the os. The electrogram recorded from a catheter placed in the narrow neck of the diverticulum revealed a very short atrioventricular time during sinus rhythm. The pathway was easily ablated using radiofrequency energy applied in the neck of the diverticulum, after multiple failed attempts at catheter ablation from the endocardial surface of the mitral annulus. Our report emphasizes the importance of searching for a coronary sinus diverticulum in all patients with posterior accessory pathways undergoing catheter ablation.