The Effects of a Bidirectional Cavo-Tricuspid Isthmus Block in Persistent Atrial Fibrillation

PURPOSE: Hybrid therapy with catheter ablation of the cavo-tricuspid isthmus (CTI) and continuation of anti-arrhythmic drugs (AAD), or electrical cardioversion with AADs might be alternative treatments for patients with persistent atrial fibrillation (AF). The goal of study was to assess the long term success rate of hybrid therapy for persistent AF compared to antiarrhythmic medication therapy after electrical cardioversion and identify the independent risk factors associated with recurrence after hybrid therapy. MATERIALS AND METHODS: A total of 32 patients with persistent AF who developed atrial flutter after the administration of a class Ic or III anti-arrhythmic drug were enrolled. This group was compared with a group (33 patients) who underwent cardioversion and received direct current cardioversion with AADs. Baseline data were collected, and electrocardiogram and symptom driven Holter monitoring were performed every 2-4 months. RESULTS: There was no significant difference in the baseline characteristics between the groups. The 12 month atrial arrhythmia free survival was better in the hybrid group, 49.0% vs. 33.1%, p=0.048. However, during a mean 55.7+/-43.0 months of follow up, the improved survival rate regressed (p=0.25). A larger left atrium size was an independent risk factor for the recurrence of AF after adjusting for confounding factors. CONCLUSION: Despite favorable outcome during 12 month, the CTI block with AADs showed outcomes similar to AAD therapy after electrical cardioversion over a 12 month follow up period. Minimal substrate modification with AADs might be an alternative treatment for persistent AF with minimal atrial remodeling.