Non-contact tissue ablation device and methods thereof

Abstract

A catheter for ablating body tissue of the interior regions of the heart includes a handle assembly, a shaft, and a distal tip section coupled to the distal end of the shaft. The distal tip section has a non-compliant and non-porous cap that has a tubular wall that defines a bore, and an ablation element that is housed inside the bore and spaced apart from the wall of the cap.

1 . A catheter for ablating body tissue of the interior regions of the heart, comprising:
 a handle assembly;   a shaft having a main lumen, a proximal end coupled to the handle assembly, and a distal end; and   a distal tip section coupled to the distal end of the shaft, the distal tip section having:
 a non-compliant and non-porous cap that has a tubular wall that defines a bore; and 
 an ablation element that is housed inside the bore and spaced apart from the wall of the cap. 
   
   
   
       2 . The catheter of  claim 1 , wherein the ablation element is a transducer. 
   
   
       3 . The catheter of  claim 1 , further including irrigation fluid in the bore between the tubular wall and the ablation element. 
   
   
       4 . The catheter of  claim 1 , wherein the cap has a closed distal tip that has an opening provided thereat. 
   
   
       5 . The catheter of  claim 1 , further including an irrigation tube extending through the lumen and having a distal end that terminates in the bore. 
   
   
       6 . The catheter of  claim 1 , further including a plurality of ring electrodes provided in spaced-apart manner about the outer surface of the shaft adjacent the distal tip section. 
   
   
       7 . The catheter of  claim 1 , further including an inner sleeve secured in the main lumen at the distal end of the shaft. 
   
   
       8 . The catheter of  claim 1 , further including an inner supporting member that extends through the main lumen of the shaft and the bore of the cap. 
   
   
       9 . The catheter of  claim 8 , wherein the inner supporting member is provided in the form of a coil, a flat wire, or a rod composed of metal, alloy or a polymer. 
   
   
       10 . The catheter of  claim 8 , further including an outer supporting member that extends through the inner sleeve and into the bore, with the inner supporting member housed in the outer supporting member. 
   
   
       11 . The catheter of  claim 1 , further including a plurality of thermocouple wires that are connected to the cap. 
   
   
       12 . The catheter of  claim 1 , further including a steering mechanism that extends in the main lumen of the shaft and which terminates at the distal end of the shaft before the location of the distal tip section. 
   
   
       13 . A method of ablating tissue at a selected treatment site, comprising:
 a. providing a catheter comprising:   a shaft having a distal end; and   a distal tip section coupled to the distal end of the shaft, the distal tip section having a non-compliant and non-porous cap that has a tubular wall that defines a bore, and an ablation element that is housed inside the bore and spaced apart from the wall of the cap;   b. positioning the distal tip section of the catheter at a desired treatment site;   c. flowing irrigation fluid to the bore between the ablation element and the cap;   d. delivering ultrasound energy to the ablation element; and   e. radiating acoustic energy in a radial manner from the ablation element, and through the irrigation fluid and the cap towards the tissue at the treatment site.   
   
   
       14 . The method of  claim 13 , wherein step (c) further includes:
 varying the flow rate of the irrigation fluid.