Long-term follow-up after catheter ablation for atrioventricular nodal reentrant tachycardia: a comparison of cryothermal and radiofrequency energy in a large series of patients

BACKGROUND: Radiofrequency (RF) catheter ablation for atrioventricular nodal reentrant tachycardia (AVNRT) is highly successful but carries a risk for inadvertent atrioventricular block. Cryoablation (cryo) has the potential to assess the safety of a site before the energy is applied. PURPOSE: The aim of this study was to evaluate the long-term efficacy and safety of cryothermal ablation in a large series of patients and compare it to RF. METHODS: All consecutive routinely performed AVNRT ablations from our centre between 1999 and 2007 were retrospectively analysed. RESULTS: In total, 274 patients were elegible: 150 cryoablations and 124 RF. Overall procedural success was 96% (262/274), and equal in both groups, but nine patients were crossed to another arm. Mean fluoroscopy time was longer in the group treated with RF (27 ± 22 min vs. cryo 19 ± 15 min; p = 0.002). Mean procedure time was not different (RF 138 ± 71 min vs. cryo 146 ± 60 min). A permanent pacemaker was necessary in two RF patients. The questionnaire revealed a high incidence of late arrhythmia related symptoms (48%), similar in both groups, with improved perceived quality of life. The number of redo procedures for AVNRT over 4.3 ± 2.5-years follow-up was not statistically different (11% after cryo and 5% after RF). CONCLUSIONS: Our data confirm that cryo and RF ablation with 4-mm tip catheters for AVNRT are equally effective, even after long-term follow-up.