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Ablation of atrioventricular nodal reentrant tachycardia: predictors of long-term success.

BACKGROUND
Atrioventricular nodal reentrant tachycardia (AVNRT) is the commonest regular supraventricular tachyarrhythmia. Ablation in the area of slow pathway (SP) has been successfully implemented in everyday clinical electrophysiological practice for more than 20 years. Although the procedure is generally regarded as effective and safe, data on long-term effects and predictors of success or failure are incomplete.


AIM
To identify predictors of successful AVNRT ablation.


METHODS
The study group consisted of 359 patients (105 males, mean age 51.1 ± 16.7 years) who underwent AVNRT radiofrequency ablation using typical combined electrophysiological and anatomical approach.


RESULTS
Acute success was achieved in 342 (95%) patients, including 187 (52%) with SP ablation and 155 (43%) with SP modification. Patients with SP modification were younger, had shorter AVNRT cycle length, less often had typical echo, and had more frequent isoproterenol usage after ablation. Long-term follow-up data was available for 308 patients (86% of the total study group). During the mean follow-up of 52.9 ± 27.3 months (median 48, range 12-130 months), 22 patients experienced AVNRT recurrences (long-term efficacy 93%). These patients had less often complete SP abolition than SP modification (27% vs. 56%, p < 0.001) and typical jump (vs. no jump or multiple jumps) at baseline (74% vs. 89%, p < 0.06) than patients without recurrences. Multivariate Cox regression analysis showed that typical jump was associated with a favourable outcome (HR 5.8, 95% CI 0.44-3.1, p = 0.0089). There were no significant differences in the use of 2 or > 2 electrode approaches between patients with or without AVNRT recurrences.


CONCLUSIONS
Typical jump and complete SP elimination are associated with a better outcome. A 2-electrode approach is as effective as > 2 electrode approach. The electrophysiological profile of patients in whom complete SP elimination was achieved may differ from that of patients in whom only SP modification was possible.