Atrioventricular nodal reentrant tachycardia with multiple discontinuities in the atrioventricular node conduction curve: Immediate success rates of radiofrequency ablation and long-term clinical follow-up results as compared to patients with single or no AH-jumps

Background: Some patients with atrioventricular nodal reentrant tachycardia (AVNRT) demonstrate multiple discontinuities (AH jump) in their antegrade AV node conduction curves. We evaluated and compared the immediate success rates, procedure-related complications, long-term clinical follow-up results and recurrence rates after slow pathway ablation in patients with multiple versus single or no AH jumps. Methods: The study group consists of 278 consecutive patients (mean age 36.6 ± 15.7) who underwent ablation for typical AVNRT, divided into three categories according to the number of AH jumps (≥50 ms) before ablation: Group-1 consisted of 63 patients (23%) with continuous AV node function curves; Group-2 of 183 patients (66%) with a single jump and Group-3 of 32 (12%) patients showing more than one AH jumps. Results: Age was significantly higher in Group-3 as compared to Group-1 (43 ± 18 years vs. 34 ± 16 years, p = 0.020). The electrophysiological features of AVNRT did not differ among groups. Before ablation, the maximum AH interval was significantly longer in Group-3 as compared to Groups-1 and -2 (p< 0.001 for both). AV node antegrade ERP was significantly shorter in Group-3 than in Group-2, both before and after ablation (p<0.050 for both). AV node Wenckebach cycle length (WCL) was shorter in Group-3 as compared to both Groups-1 and -2, before and after ablation (p < 0.050 for all). AV node WCL was prolonged significantly in all groups after ablation (p < 0.001 for all). Residual dual pathways were present in 37 of 278 patients (13%) after ablation and were significantly more frequent in Group-3 than Group-2 (31% vs. 15%, p = 0.023). Conclusions: Patients with multiple AH jumps are older and more often have residual dual atrioventricular nodal pathway physiology after successful ablation but these features do not affect the immediate and long-term success rates of slow pathway ablation as compared to patients with single or no AH jumps.