Endpoints for Successful Slow Pathway Catheter Ablation in Typical and Atypical Atrioventricular Nodal Re-Entrant Tachycardia A Contemporary, Multicenter Study

OBJECTIVES This study sought to investigate markers of success following slow pathway ablation for atrioventricular nodal re-entrant tachycardia (AVNRT). BACKGROUND Published data are conflicting. METHODS The authors studied 1,007 patients with typical AVNRT and 77 patients with atypical AVNRT. RESULTS Following ablation, tachycardia was rendered not inducible in all patients. One case of transient (0.09%) and 1 of permanent (0.09%) atrioventricular (AV) block were encountered. At a 3-month follow-up, arrhythmia recurrence was noted in 21 (2.10%) patients in the typical and 3 (3.90%) patients in the atypical group (odds ratio: 0.525; 95% confidence interval [CI]: 0.153 to 1.802; p = 0.298). To predict absence of recurrence in 3 months, the induction of junctional rhythm (95.70% in typical and 96.10% in atypical groups) had sensitivity of 95.9% (95% CI: 94.6% to 97.0%) and specificity of 4.20% (95% CI: 0.11% to 21.10%), while the absence of dual AV nodal conduction post-ablation had sensitivity of 65.2% (95% CI: 62.2% to 68.1%) and specificity of 33.30% (95% CI: 15.60% to 55.30%). Neither junctional rhythm nor residual dual AV nodal pathway conduction were predictive of arrhythmia recurrence by univariate analysis. In long-term follow-up data available for 239 patients, arrhythmia-free survival was not associated with the induction of junctional rhythm or the absence of residual dual AV nodal conduction (log-rank test, p = 0.819 and p = 0.226, respectively). CONCLUSIONS Induction of a junctional rhythm during ablation is a sensitive but not a specific marker of success. Residual dual AV nodal conduction is not predictive of recurrence. Noninducibility of the arrhythmia, usually after ablation-induced junctional rhythm, and despite isoproterenol challenge, is the most credible endpoint for success. (C) 2019 by the American College of Cardiology Foundation.