COAXIAL CATHETER INSTRUMENTS FOR ABLATION WITH RADIANT ENERGY

摘要

Ablation methods and instruments are disclosed for creating lesions in tissue, especially cardiac tissue for treatment of arrhythmias and the like. Percutaneous ablation instruments in the form of coaxial catheter bodies are disclosed having at least one central lumen therein and having one or more balloon structures at the distal end region of the instrument. The instruments include an energy emitting element which is independently positionable within the lumen of the instrument and adapted to project radiant energy through a transmissive region of a projection balloon to a target tissue site. An ablative fluid can also be employed outside of the instrument to ensure efficient transmission of the radiant energy when the instrument is deployed. In another aspect of the invention, mechanisms are disclosed for determining whether the instrument has been properly seated within the heart. This contact-sensing feature can be implemented by an illumination source situated within the instrument and an optical detector that monitors the level of reflected light. Measurements of the reflected light can thus be used to determine whether contact has been achieved and whether such contact is continuous over a desired ablation path.