The purpose of this retrospective study is to describe why and when we used cryo and why we crossed over when we used both RFA and cryo. It is also to determine if there is some predictor that would make us say one patient would be better served with one technique than another and to describe our overall acute success rate and then our 6-month recurrence rate with cryo ablation and compare it to our known success rate with RFA.

Cryotherapy (Cryo) is a new ablation energy source used instead of the radiofrequency (RFA) method for ablation of septal pathways. In the past year, we have used cryo approximately 50 times, however 50% of the cryo procedures crossed over from RFA to cryo or cryo to RFA. It appears to me that cryo use should be as an adjunct therapy to RFA instead of replacement of RFA.

I would like to describe why and when we used cryo and why we crossed over when we used both RFA and cryo. I would like to determine if there is some predictor that would make us say one patient would be better served with one technique than another. I would also describe our overall acute success rate and then our 6-month recurrence rate with cryo ablation and compare it to our known success rate with RFA. All of this can be done with a chart review.

This will be done through a retrospective study.

Inclusion Criteria:

• charts between January 1 and 2004 to December 31, 2004
• pediatric population
• those who were ablated

Exclusion Criteria:

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