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Treatment of atrioventricular nodal re-entrant tachycardia by cryoablation with a 6 mm-tip catheter vs. radiofrequency ablation.

AIMS
To compare recurrence rate and other procedural characteristics in patients undergoing atrioventricular nodal re-entrant tachycardia (AVNRT) treatment with catheter cryoablation (CRYO) delivered by 6 mm-tip catheter or radiofrequency (RF) ablation.


METHODS AND RESULTS
This is a retrospective case-control study including 80 patients with AVNRT treated with CRYO from March 2002 to June 2008. They were compared with another 80 consecutive patients who underwent RF ablation for AVNRT within the same period. Procedural success of 97.5 and 95% were achieved in CRYO and RF group, respectively. There was no permanent atrioventricular block (AVB) in the CRYO group, whereas two (2.5%) patients developed permanent first-degree or second-degree AVB in RF group (P = 0.155). Higher recurrence was found in the CRYO group (9 vs. 1.3%; P = 0.032) with no difference in the composite endpoint of procedural failure and recurrence between the groups (P = 0.263). There was significantly shorter fluoroscopy time (18.6 +/- 10.8 vs. 25.9 +/- 17.0 min; P = 0.002) and more energy applications required (3.1 +/- 1.7 vs. 1.9 +/- 1.1; P < 0.001) in the CRYO than the RF group.


CONCLUSION
Compared with RF ablation, CRYO with 6 mm-tip catheter for treating AVNRT results in higher recurrence and potentially lower incidence of permanent AVB. Fluoroscopy time has been shown to be reduced by CRYO.