Bi-modal linear and loop ablation catheter, and method

Abstract

Medical devices, systems, and methods for treating patients with tissue ablation include catheter systems having hi-modal steering mechanisms, which are capable of both linear and loop ablation. In other words, the catheter system may have two different steering modes: two-dimensional and three-dimensional. In the first and second steering modes, the steering actuator may cause one or more portions of the catheter shaft to bend in different planes. A steerable ablation catheter may include treatment elements such as electrodes at its distal end and along the catheter shaft, each of which may map, pace, and ablate. Optional features include a series of thermocouples for monitoring local temperatures.

What is claimed is: 
     
         1 . A method of medical treatment, the method comprising:
 providing a medical device including a catheter body, at least one steering actuator, and a plurality of treatment elements;   directing the plurality of treatment elements toward a tissue region;   selecting one of a first steering mode and a second steering mode:
 in the first steering mode, manipulating the at least one steering actuator in a first direction from an initial position to cause a first portion of the catheter body to bend from an initial shape to a first arc shape along a first plane; 
 in the second steering mode, manipulating the at least one steering actuator in a second direction from the initial position to cause the first portion to bend from the initial shape to a second arc shape, and to cause a second portion of the catheter body to bend along a second plane; and 
   activating the plurality of treatment elements.   
     
     
         2 . The method of  claim 1 , wherein the catheter body has a first portion with a first plane of preferential bending and a second portion with a second plane of preferential bending, the first portion being distal to the second portion. 
     
     
         3 . The method of  claim 2 , wherein the first portion has a higher flexibility than the second portion. 
     
     
         4 . The method of  claim 1 , wherein the medical device further includes a guide plate within the catheter body, the guide plate having a proximal portion, a distal portion, and a transition portion. 
     
     
         5 . The method of  claim 4 , wherein the guide plate distal portion is within the first portion of the catheter body and the guide plate proximal portion is within the second portion of the catheter body. 
     
     
         6 . The method of  claim 5 , wherein, in the first steering mode, the at least one steering actuator is manipulated from the initial position to cause the guide plate distal portion to bend in a first direction in the first plane of preferential bending. 
     
     
         7 . The method of  claim 6 , wherein, in the second steering mode, the at least one steering actuator is manipulated from the initial position to cause:
 the guide plate distal portion to bend in a second direction in the first plane of preferential. bending; and   the guide plate proximal portion to bend in the second plane of preferential bending.   
     
     
         8 . The method of  claim 7 , wherein the guide plate further has:
 a first outer edge;   a second outer edge;   a longitudinal axis;   a width that extends direction from the first outer edge directly to the second outer edge and that is perpendicular to the longitudinal axis;   a length that is located along the longitudinal axis; and   a transition portion between the proximal portion and the distal portion, the proximal portion having:
 a distal section; 
 a proximal section; and 
 a middle section located directly between the distal section and the proximal section, the middle section having a width that extends directly from the first outer edge of the guide plate directly to the second outer edge of the guide plate. 
   
     
     
         9 . The method of  claim 8 , wherein:
 the distal section and the proximal section are linear and located along the guide plate longitudinal axis; and   an entirety of the middle section has an arc of curvature when the catheter body is in an at least substantially linear configuration.   
     
     
         10 . The method of  claim 5 , wherein the medical device further includes a stiffening element longitudinally movable within the catheter body between a proximal position and a distal position. 
     
     
         11 . The method of  claim 10 , further comprising moving the stiffening element to the distal position in the first steering mode. 
     
     
         12 . The method of  claim 11 , wherein the stiffening element is configured to oppose bending of the proximal portion of the guide plate in the first steering mode. 
     
     
         13 . The method of  claim 11 , further comprising moving the stiffening element to the proximal position in the second steering mode. 
     
     
         14 . The method of  claim 2 , wherein the at least one steering actuator includes a first steering actuator and a second steering actuator and the catheter body further has a third portion proximal to the second portion, the method further comprising:
 manipulating the second steering actuator from an initial position to cause the third portion to bend from an initial shape to an arc shape.   
     
     
         15 . The method of  claim 1 , further comprising mapping electrical activity of the tissue region with the plurality of treatment elements. 
     
     
         16 . The method of  claim 1 , wherein the medical device further includes a plurality of thermocouples, the method further comprising monitoring a temperature of each of the plurality of treatment elements with the plurality of thermocouples. 
     
     
         17 . A method of medical treatment, the method comprising:
 providing a medical device including:
 a catheter body, the catheter body having a first portion with a first plane of preferential bending and a second plane of preferential bending, the first portion being distal to and more flexible than the second portion; 
 a steering actuator; 
 a plurality of treatment elements; and 
 a guide plate having a proximal portion, a distal portion, and a transition portion, the guide plate distal portion being within the first portion of the catheter body and the guide plate proximal portion being within the second portion of the catheter body; 
   directing the treatment elements toward a tissue region;   selecting one of a first steering mode and a second steering mode:
 in the first steering mode, manipulating the at least one steering actuator in a first direction from an initial position to cause the guide plate distal portion to bend in a first direction in the first plane of preferential bending; 
 in the second steering mode, manipulating the at least one steering actuator in a second direction from the initial position to cause the guide plate distal portion to bend from in a second direction in the first plane of preferential bending and to cause the guide plate proximal portion to bend along the second plane of preferential bending; 
   directing the plurality of treatment elements such that at least one of the plurality of treatment elements is in contact with the tissue region; and   activating the plurality of treatment elements.   
     
     
         18 . The method of  claim 17 , wherein the guide plate further has:
 a first outer edge;   a second outer edge;   a longitudinal axis;   a width that extends direction from the first outer edge directly to the second outer edge and that is perpendicular to the longitudinal axis; and   a length that is located along the longitudinal axis,   the proximal portion further having:
 a linear distal section; 
 a linear proximal section; and 
 a middle section located directly between the distal section and the proximal section, the middle section having a width that extends directly from the first outer edge of the guide plate directly to the second outer edge of the guide plate, an entirety of the middle section having an arc of curvature when the catheter body is in an at least substantially linear configuration. 
   
     
     
         19 . The method of  claim 17 , wherein the medical device further includes a stiffening element longitudinally movable between a proximal position and a distal position, the method further comprising:
 moving the stiffening element to the distal position in the first steering mode; and   moving the stiffening element to the proximal position in the second steering mode.   
     
     
         20 . A method of medical treatment, the method comprising:
 providing a medical device including:
 a steerable catheter body having a first portion with a first plane of preferential bending and a second portion with a second plane of preferential bending, the first portion being distal of the second portion; 
 a steerable outer sheath at least partially surrounding and being movable with respect to the steerable catheter body; 
 a first steering actuator in mechanical communication with the steerable catheter body; 
 a second steering actuator in mechanical communication with the steerable outer sheath; and 
 a plurality of treatment elements on the steerable catheter body; 
   directing the plurality of treatment elements toward a tissue region;   selecting one of a first steering mode and a second steering mode:
 in the first steering mode, manipulating the first steering actuator in a first direction from an initial position to cause a first portion of the catheter body to bend from a first shape to a second shape along a first plane; 
 in the second steering mode, manipulating the first steering actuator in a second direction from the initial position to cause the first portion to bend from the first shape to a third shape, and to cause a second portion of the catheter body to bend along a second plane; 
   manipulating the second steering actuator from an initial position to cause a portion of the steerable outer sheath to bend from a first shape to a second shape; and   activating the plurality of treatment elements to ablate the tissue region.