Remaining challenges in catheter ablation of accessory pathways: rare entity of coronary sinus diverticulum-associated pathways

A limited number of case reports of coronary sinus (CS) diverticula complicating catheter ablation have been published. We retrospectively analysed 2245 patients who underwent ablation of an accessory pathway (AP) at our institution between 1/11/1993 and 31/10/2016. Eight patients (0.36%) were found to have a CS diverticulum in venography. APs showed a mean antegrade conduction time of 276 ± 23 ms (range 220–310 ms) and a mean retrograde conduction of 301 ± 45 ms (230–350 ms). Four patients had 1 (n = 2), 2 (n = 1), or 3 (n = 1) previously failed ablation attempts. Pathways could not be ablated with a conventional 4 mm tip catheter in 7 of 8 cases. In seven patients, ablation was successful, in two using an 8-mm ablation catheter, in two using cryoablation, and in the remaining three with an irrigated tip ablation catheter. After failed femoral approach, one 9-year-old female was successfully ablated via the right jugular vein. In one 75-year-old female, ablation was not successful. During a mean follow-up of 8.9 ± 6.4 years, all patients remained free of recurrences. In inferoseptal pathways, especially with previous failed ablation attempts, venographies of the CS should be performed. After successful ablation long-term prognosis is excellent.