Indian Pacing and Electrophysiology Journal (Aug 2008)
Importance of the relationship between sinus cycle length and junctional rhythm cycle length (occured during radiofrequency ablation) in predicting the successful modification of the slow pathway in Atrioventricular Nodal Re-entrant Tachycardias
Abstract
Background: In atrioventricular nodal re-entrant tachycardias (AVNRT), the achievement of Junctional Rhythms (JR) during Radiofrequency Ablation (RF) is a sensitive but non-specific marker of success. Our aim is to analyze prospectively the predictors of non-inducibility of AVNRT, focusing on the characteristics of the JR.Methods: We included 75 patients with reproducibly inducible AVNRT. Ablation was performed following an electro-anatomical approach. After each application, the induction protocol was repeated. Results: A total of 341 applications were performed. Although the achievement of ≥1 JR was necessary to obtain the non-inducibility, and the cumulative number of junctional beats (CJB) was higher in effective applications, no CJB cut-off was associated with a success rate higher than 75%. After the observation of a significant correlation between the sinus cycle length (CL) pre-RF and the CL of the JR (JR-CL) (c=0.52; p<0.001), the sinus CL pre-RF/JR-CL ratio (CL-ratio) adequately differentiated the successful vs. unsuccessful applications: 1.41±0.23 vs. 1.17±0.2 (p<0.001). In a multivariate analysis, a CBJ 11 (p<0.001) and a CL-ratio 1.25 (p<0.001) were found to be the only independent predictors of success. The combination of ≥ 11 of CJB with a CL ratio ≥ 1.25 achieved non-inducibility in 97% of our patients. Conclusions: 1) The specificity of the occurrence of JR as a marker of the successful ablation of AVNRT is increased by the CL-ratio. 2) The achievement of ≥ 11 of CJB with a CL ratio ≥ 1.25 predicts non-inducibility in almost all patients.
