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Strategies & Market Trends : Zeev's Turnips - No Politics -- Ignore unavailable to you. Want to Upgrade?

To: charles shaw who wrote (11102)	12/6/2001 11:57:32 AM
From: Zeev Hed	Read Replies (3) \| Respond to of 99280

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

To: charles shaw who wrote (11102)	12/6/2001 6:11:24 PM
From: Ausdauer	Respond to of 99280

Charley, discrete foci are responsible for AFib... ...in only a small minority of the millions of patients with this disorder. Radiofrequency ablation or cryoablation of the pulmonary veins is a technically demanding procedure which is pursued in those will foci in those locations. I don't expect this will ever be a high volume procedure for most operators and there are complications to such procedures which can be difficult to manage. The question of whether there percutaneous cryoablation will replace radiofrequency ablation is an interesting one. I guess I would have to ask a colleague as to practice trends. At the present time most practitioners were trained with RF devices, so acceptance will be slow unless there are distinct advantages to cryoablation. FWIW, Aus