Comparison of Cryo- vs. Radio-Frequency-Current-Ablation in Patients with AV-Nodal-Reentry-Tachycardia

Introduction: Cryo-ablation [CrA] is a safe treatment for av-nodal-reentry-tachycardia [AVNRT] concerning the development of heart block, but may have a lower efficacy as radiofrequency-ablation [RFA].

Methods: We analyzed efficacy and safety of CrA vs. RFA in pts with AVNRT. End points were non-inducibility of tachycardia, absence of dual av-nodal physiology [DAVNP], (ah-jump>50ms during atrial extra pacing), and/or absence of sustained slow pathway conduction [SSPC].

Results: From 2003 to 2013 we treated n=98 pts with AVNRT by RFA (n=62) or CrA (n=36). Mean age was 12.6±3.4 ys in the CrA- and 12.5±3.6 ys in the RFA-group, mean follow up 4.9±1.5 and 5.5±3.5 ys, respectively. CrA was effective in 32/36 pts (89%) and in all with RFA. In four pts which could not be treated by CrA we switched to RFA during the procedure, so n=66 pts were ablated by RFA. Two out of 62 pts (3.2%) in the RFA group and one of the four pts in whom we switched to RFA got complete heart block. Thus the risk for heart block is 3/66 (4.5%) for all RFA pts. None of the pts treated with CrA developed heart-block. Seven of the 32 pts (22%) after CrA and 2/66 pts (3%) in the RFA-group had recurrence of AVNRT. Two pts in the CrA group were definitely treated by another CrA and three by a RFA. Two got recurrance after another CrA and were finally treated by RFA. Two recurrences in the RFA-group were treated by a second RFA. All together 9/32 pts (28%) could not be treated by CrA , but by RF-energy.

Conclusions: CrA is very safe for the ablation of AVNRT , but has a lower efficacy and a higher recurrence rate. In contrast, RFA is highly effective but associated with a risk for complete heart block. Switching from CrA to RFA is probably associated with a higher risk for complete heart block.