Effective Approaches to Successful Target Sites in Catheter Ablation of the Right-side Accessory Pathways

Cho, Jeong Gwan; Park, Woo Suck; Bae, Youl; Ahn, Young Keun; Rhew, Jay Young; Kim, Nam Ho; Lee, Sang Hyun; Park, Hyung Wook; Park, Joo Hyung; Jeong, Myung Ho; Park, Jong Chun; Kang, Jung Chaee

Abstract

BACKGROUND: Although radiofrequency catheter ablation (CA) of the accessory pathway (AP) is very effective and safe, it has been reported that CA is more difficult in the right-side AP than the left-side AP, requiring the refinement of the conventional CA technique for the right-side AP. This study was, therefore, aimed to develop an effective technique for CA of the right-side AP.
METHODS
Fifty right-side APs in 45 patients which underwent CA were included in this study. The locations of APs were divided into 8 regions (anteroseptal, mid septal, posteroseptal, posterior, posterolateral, lateral, anterolateral, and anterior). After localizing APs, CA of the APs was attempted via the inferior vena cava (IVC) in all patients. If CA attempt via the IVC for more than 1 hour was failed, then CA was tried via the superior vena cava (SVC). Successful CA was defined as permanent loss of AP conduction even during infusion of isoproterenol (1-4microg/min). The ways of approaching the ablation catheter to the successful target sites were classified into over-the-tricuspid valve approach (OV) via the IVC (IVC-OV), OV via the SVC (SVC-OV), under-the-tricuspid valve (UV) approach via the IVC (IVC-UV), and UV via the SVC (SVC-UV) and evaluated according to the AP locations.
RESULTS
The locations of the APs were anteroseptal in 5 APs, mid septal in 6, posteroseptal in 12, posterior in 3, posterolateral in 5, right lateral in 11, anterolateral in 4, and anterior in 4. Forty-eight (96.0%) of 50 APs were successfully ablated; 35 (70.0%) with primary IVC approaches and 13 (26.0%) with secondary SVC approaches. As a successful approach, IVC-OV was 26 (54.2%); IVC-UV, 9 (18.8%); SVC-OV, 4 (8.3%), and SVC-UV, 9 (18.8%). Secondary SVC approaches were required 7 (70.0%) in the lateral APs, 2 (50.0%) in the anterolateral APs, 1 (25.0%) of the posterolateral APs, 1 (25.0%) in the anterior APs, 1 (20.0%) of the anteroseptal APs, and 1 (8.3%) in the posteroseptal APs but none in the midseptal and posterior APs. SVC-UV approach was used in 9 (69.2%) in 13 APs which were ablated with SVC approach.
CONCLUSIONS
The ways of approach to successful target site in CA of the right-side APs are different according to the location and SVC approaches are frequently required in ablation of the lateral or anterolateral APs. Therefore, SVC approaches should be considered in these locations if the initial IVC approaches are not successful.