Originally, it was conceived for for two types of pathologies, additional foci or reentrant circuits. Reentrant circuits can be highly localized, as in ventricular tachycardia postinfarction or AV node reentry, and these were out first target. It is believed (from open chest cardio ablation results) that cryoabalation scar tissue does not have a tendency to become a new arrhytmogenic focus as do most thermal 9and RF are thermal as well). The additional big advantage is the mapping enabled before the procedure, since cooling the target tissue to about 5 centrigrade stops the electrical activity (sodium channels narrowing, I believe), thus enabling the positioning of the active catheter "head" before ablation (you target a suspected tissue, cool to 5 C, if arrhytmia stops, you are at the right spot, if not, you "guess" another spot, no damage done). I believe that since then, the technology of electrical mapping of the heart by independent means has advanced, but this device still allows you a single secure way to make sure you are ablating the right tissue.
Zeev
Zeev |
