Objectives Limited data exists about long term success rate after ablation of right ventricular outflow tract (RVOT) ventricular arrhythmias (VA) guided by the non-contact mapping system (NCM). In this study, we aim to investigate long term outcomes following NCM guided RVOT VA ablation.
Methods From June 2006 to December 2011, consecutive patients with RVOT VA underwent mapping and ablation using NCM (group A, n = 136) or 3-D contact mapping system (control group B, n = 18). Within group A, ablation was randomised to be initiated at either the site of earliest electrical activity (EA site) or the break-out site from which rapid centrifugal electrical propagation originated from (BO site). Clinic visits, ECGs and 24 hour Holters were conducted monthly for the first three months and then in six months intervals.
Results 154 (60 male, mean age 41.8 ± 13.5 years old) consecutive patients were enrolled. With follow up of 36.2 ± 17.5 months, the long term success rate after a single procedure without anti-arrhythmic agents was 86.8% (118/136) in the NCM cohort. Baseline characteristics, acute and long term success rates, complications were similar between Groups A and B. A learning curve of 20 cases was associated with the use of NCM. The initial ablation is more successful when directed at the EA sites rather than the BO sites identified by NCM (p < 0.01).
Conclusions NCM-guided RVOT VA ablation is highly effective and associated with long term clinical outcomes comparable to ablation guided by 3-D mapping systems. Ablation is more successful when directed at the EA sites identified by the NCM.