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Publication Date: 2008-Jul-01
Document File: 5 page(s) / 289K

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The Prior Art Database

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Disclosure No. 07-D1183




    Cryogenic catheters are used to treat, among other things, cardiac arrhythmias. For example, atrial fibrillation of the heart may be treated by application of very cold temperatures to selected portions of heart tissue. Typically, the cryogenic temperatures are delivered via a catheter or the like that has a balloon or the like disposed on a distal end thereof. Atrial fibrillation, or Afib, is the most common cardiac arrhythmia and affects approximately 6 million patients around the globe.

    Cryoablation catheters generally include an elongate member that has a balloon disposed at a distal end. The balloon receives a cryogenically cooled fluid or gas that creates very cold temperatures on the surface of the balloon. The freezing temperatures create an electrical block by damaging the cellular tissue. The damaged area creates scar tissue that prevents an electrical pathway. It is this electrical pathway that causes the heart to beat. Aberrant electrical pathways cause aAfib and are isolated or treated by selective ablation of heart tissue.

    Tissue damage to a single spot seldom creates the correction required for the heart to correct itself with regards to Atrial Fibrillation (i.e., to change from an irregular heartbeat to one that will efficiently drive the blood). Many times a RF catheter will be dragged to create a linear, U-shaped, or circular shaped burn. This again will damage the tissue to create an electrical block. Freezing the tissue with a cryoablation catheter will result in similar damage. The electrical pathway will either end or find a new pathway. This procedure may result in correction of the heart beat.


Page 2 of 5

Disclosure No. 07-D1183

    There is a need for a single cryoablation catheter that has a balloon that has the ability to secure itself to a location on the treated tissue without movement. Once the balloon is secured, the tissue of interest can be treated without worrying about the balloon moving around and contacted other surrounding tissues. There is also a need for balloons having the appropriate size and shape. For example, the balloon could adhere to a contact area and the fill in the remaining area. Such a system makes sense if the balloon is designed so that it does not slip out of place.


    FIG. 1 illustrates a schematic illustration of a cryogenic catheter 10. The cryogenic catheter 10 includes an inflatable member 12 or balloon 12 disposed on the distal end thereof that is used to form the cold contact surface for contact with the treated tissue. Cryogenic fluid (e.g., nitrous oxide) is pumped or otherwise delivered to the balloon 12 to create the freezing contact surface. In one aspect of the invention, the balloon 12 has one or more surface features 14 disposed about al...