Ablation catheter having flexible tip with multiple flexible electrode segments

Abstract

A catheter apparatus comprises an elongated catheter body having a distal end, a proximal end, and at least one fluid lumen extending longitudinally therein; and a plurality of flexible electrode segments on a distal portion of the catheter body adjacent the distal end, each pair of neighboring flexible electrode segments being spaced from each other longitudinally by a corresponding electrically nonconductive segment. Each flexible electrode segment comprises a sidewall provided with one or more elongated stiffness reductions extending through the sidewall, the one or more elongated stiffness reductions providing flexibility in the sidewall for bending movement relative to a longitudinal axis of the catheter body. The electrically nonconductive segment is substantially smaller in length than each of the corresponding pair of neighboring flexible electrode segments.

1 .- 21 . (canceled) 
     
     
         22 . A catheter apparatus comprising:
 an elongated catheter body having a distal portion, a proximal end, and at least one fluid lumen extending longitudinally therein;   a first flexible electrode segment on the distal portion of the catheter body, the first flexible electrode segment energizable to form a first ablation zone;   a second flexible electrode segment spaced apart longitudinally from the first flexible electrode segment on the distal portion of the catheter body, the second flexible electrode segment energizable to form a second ablation zone that overlaps with the first ablation zone to form a continuous lesion, wherein each of the first and second flexible electrode segments comprises a sidewall provided with one or more elongated stiffness reductions extending through the sidewall; and   a third electrode positioned longitudinally between the first and second flexible electrode segments.   
     
     
         23 . The catheter apparatus of  claim 22 , wherein the third electrode is a band electrode. 
     
     
         24 . The catheter apparatus of  claim 22 , further comprising an electrically nonconductive segment positioned between the first and second flexible electrode segments. 
     
     
         25 . The catheter apparatus of  claim 24 , wherein the corresponding electrically nonconductive segment is not as flexible as the neighboring flexible electrode segments. 
     
     
         26 . The catheter apparatus of  claim 24 , wherein the electrically nonconductive segment is sufficiently small in length to provide substantially continuous flexibility across the flexible electrode segments and the corresponding electrically nonconductive segment. 
     
     
         27 . The catheter apparatus of  claim 22 , wherein the first and second flexible electrode segments are biased to stretch lengthwise. 
     
     
         28 . The catheter of  claim 22 , wherein the at least one fluid lumen includes a lumen extension member extending at least partially through the first and second flexible electrode segments, the lumen extension member having a plurality of openings configured and arranged to produce a predetermined fluid flow from the lumen extension member through the first and second flexible electrode segments. 
     
     
         29 . The catheter of  claim 22 , further comprising a measurement circuit coupled with the third electrode. 
     
     
         30 . The catheter of  claim 29 , wherein the measurement circuit is coupled to the first and second flexible electrode segments. 
     
     
         31 . The catheter of  claim 22 , wherein the third electrode is a diagnostic electrode. 
     
     
         32 . The catheter of  claim 22 , wherein a ratio between a length of the first and second flexible electrode segments and a diameter of the distal portion is less than 1.7. 
     
     
         33 . The catheter of  claim 24 , wherein the electrically nonconductive segment is less than 1.09 times of a diameter of the distal portion. 
     
     
         34 . A distal portion for a catheter, the distal portion comprising:
 a first flexible electrode segment energizable to form a first ablation zone;   a second flexible electrode segment spaced longitudinally from the first flexible electrode segment, the second flexible electrode segment energizable to form a second ablation zone that overlaps with the first ablation zone to form a continuous lesion, wherein each of the first and second flexible electrode segments comprises a sidewall provided with one or more elongated stiffness reductions extending through the sidewall; and   a third electrode positioned longitudinally between the first and second flexible electrode segments.   
     
     
         35 . The distal portion of  claim 34 , further comprising an electrically nonconductive segment that is positioned between the first and second flexible electrode segments. 
     
     
         36 . The distal portion of  claim 35 , wherein the electrically nonconductive segment is not as flexible as the neighboring flexible electrode segments. 
     
     
         37 . The distal portion of  claim 35 , wherein the electrically nonconductive segment is sufficiently small in length to provide substantially continuous flexibility across the flexible electrode segments and the electrically nonconductive segment. 
     
     
         38 . The distal portion of  claim 34 , wherein the third electrode is a band electrode. 
     
     
         39 . The distal portion of  claim 34 , wherein the third electrode is configured to be coupled with a measurement circuit. 
     
     
         40 . The distal portion of  claim 39 , wherein the first and second flexible electrode segments are configured to be coupled with the measurement circuit. 
     
     
         41 . The distal portion of  claim 34 , wherein the third electrode is a diagnostic electrode.