Introduction: Radiofrequency ablation of some right-sided accessory pathways continues to be challenging. The purpose of this study was to evaluate the efficacy of introducing a multielectrode microcatheter in the right coronary artery to localize accessory pathways when conventional mapping was unsuccessful.
Methods and results: A retrospective study was conducted of all right-sided accessory pathway radiofrequency ablation procedures in which a multielectrode microcatheter as a reference in the right coronary artery was used to assist mapping. Between January 1998 and January 2002, 10 patients (5 males) underwent mapping of 11 accessory pathways with this technique at mean age of 12.3 +/- 3.8 years. Five patients had Ebstein's anomaly of the tricuspid valve. Accessory pathways were identified in the following locations: right anterior 3, right anterolateral 2, right lateral 1, right posterolateral 2, and right posterior 3. Mean procedure time was 285 +/- 70.3 minutes, and fluoroscopy time was 68.7 +/- 21 minutes. Average mapping duration prior to microcatheter insertion in the right coronary artery was 136 +/- 40 minutes. After microcatheter placement in the right coronary artery, the time to successful ablation of accessory pathways was 38 +/- 11 minutes. All 11 (100%) accessory pathways were successfully ablated.
Conclusion: Mapping in the right coronary artery with a microcatheter is an effective method to improve localization and successful ablation of difficult right-sided accessory pathways.