[ 0023 ] fig1 a to 1 c are three perspective views 10 a , 10 b and 10 c , respectively , of a portion of a telescoping tip electrode catheter 11 with a steerable portion 14 of the main catheter body 16 just proximal of the telescoping tip portion 18 according to an embodiment of the present invention . more particularly , fig1 a shows the catheter 12 including a main body portion 16 and a telescoping tip portion 18 . the telescoping tip portion of this fig1 a also shows the tip electrode 20 . fig1 b shows the steerable portion 14 of the main catheter body 16 just proximal of the telescoping tip portion 18 . the portion 18 includes a partially extended mandrel 22 which extends from and retracts to the main catheter body 16 and to which the telescoping tip electrode 20 attaches . fig1 c shows the steerable portion 14 engaged in a curve with a greater degree of curvature than the catheter portion 10 b and the mandrel 22 extended to a greater length than the mandrel 22 in the catheter portion 10 b . in alternative embodiments of the present invention , the tip electrode 22 can be retracted inside the catheter main body 16 rather than being external to the catheter main body 16 when the mandrel 22 is retracted to its full extent . [ 0024 ] fig2 is a side view of the handle portion 30 and the distal portion of the catheter main body 16 including the telescoping tip electrode 20 and the steerable portion 14 of the catheter main body 16 according to the fig1 a to 1 c embodiments . the handle portion 30 includes a slider mechanism 32 which operates the telescoping tip 18 . the mechanism 32 moves in increments along the longitudinal axis of the catheter 10 and is connected in the interior ( not shown ) of the catheter 10 to the mandrel 22 for the telescoping tip 20 . movement of the slider mechanism 32 in either direction similarly causes the mandrel 22 to move in the same direction in order to extend or retract the tip electrode 20 . for example , movement of the slider mechanism 32 proximally causes the mandrel 22 and the tip electrode 20 to retract and movement of the slider mechanism 32 distally causes the mandrel 22 and the tip electrode 20 to extend . the mechanism 32 can also be manipulated to cause partial movement of the mandrel 22 and tip electrode 20 so that partial extension at varying lengths of the tip electrode 20 can be achieved . a slider mechanism which can be used for an embodiment of the present invention is also disclosed in u . s . pat . no . 6 , 178 , 354 , to charles gibson arid issued on jan . 23 , 2001 , which is incorporated herein in its entirety by reference . the handle portion 30 also includes a thumbwheel 34 which operates the steerable portion 14 of the catheter main body . the thumbwheel 34 and operation of the steerable portion 14 is described in u . s . pat . no . 5 , 611 , 777 , to bowden et al . and issued on mar . 18 , 1997 , which is incorporated herein in its entirety by reference . the handle portion 30 also connects to a generator device 36 which is proximal of the portion 30 . the generator device portion 36 is used in a conventional manner to connect to a wire which carries power to the tip electrode 20 . such device 36 and operation is well known to those of ordinary skill in the art and therefore will not be further described herein . [ 0025 ] fig3 is an exploded perspective view of the telescoping tip electrode 20 according to the fig1 a to 1 c embodiments . in this embodiment , a bipolar electrode 20 is used , including three interlocking portions 38 , 40 and 42 . portions 38 and 42 provide an elliptical shape to the electrode 20 and are the conducting portions . portion 40 can be an electrical insulation . exemplary materials for the construction of the electrode 2 are platinum , platinum / iridium or gold , etc . an exemplary size of the electrode 20 is 9 french with a length which can vary between about 4 to 8 mm . in alternative embodiments , the electrode 20 size can be smaller than the outer diameter of the main catheter body 16 so that the electrode 20 can retract inside the catheter 10 . in further alternative embodiments , the electrode 20 can be a split electrode or any other type of shape ( e . g ., square , rectangular or circular ) electrode 20 operable to treat tissue in a cardiac or arterial passageway . [ 0026 ] fig4 is a first partial cross sectional view of the telescoping tip electrode 20 according to the fig1 a to 1 c embodiments . the electrode 20 includes conductors 44 and 46 which provide power to the portions 38 and 42 . conductors 44 and 46 extend through the mandrel 22 to the generator device 36 ( shown in fig2 ). also shown is a soldering bonding junction 48 between the electrode 20 and the mandrel 22 . [ 0027 ] fig5 is a second partial cross sectional view of the telescoping tip electrode 22 according to the fig1 a to 1 c embodiments . shown are a temperature sensor 50 and circumferential grove 52 around the electrode 20 for sensor placement . the soldering junction 48 is also shown between the electrode 20 and the mandrel 22 . referring also to fig1 c and 2 , an exemplary material for the mandrel 22 is nitinol , mp35n and sst . in alternative embodiments , where the mandrel 22 is not the electrical conductor , the material choices can be expanded to include non - conductive plastics that are durable but flexible , such as polyimide , peek or nylon , etc . in one embodiment , the length of the mandrel 22 and telescoping tip 20 portion 18 which extends or retracts from the main catheter body 16 can range in length from greater than 0 cm to about 6 cm or more in length . the diameter of the mandrel 22 can be 7 french for example . in alternative embodiments , the mandrel 22 diameter can be just smaller than the inner diameter of the main catheter body 16 shaft . [ 0028 ] fig6 is a side view of the telescoping tip portion 18 including the mandrel 22 on which the telescoping tip electrode 20 is mounted ( not shown ) and the portion of the catheter main body 16 just proximal of the telescoping tip portion 18 according to the fig1 a to 1 c embodiments . the portion of the main catheter body 16 includes a bonding area 60 in which the mechanisms to add in the steerability of the catheter 10 reside . also shown in this embodiment is a ring electrode 62 for use in bipolar recordings , as is conventional . fig7 is a partial cross section of the proximal portion of the main catheter body 16 according to the fig1 a to 1 c embodiments which shows the bonding area 60 in more detail . more particularly , the area 60 includes a steering anchor 64 and a threaded core assembly 66 for use in controlling the steerable portion 14 of the main catheter body 16 . [ 0029 ] fig8 is a partial cross section of the telescoping tip electrode catheter 10 showing the steering cables 70 and 72 for the steerable catheter portion 14 . in this embodiment , the steerable portion 14 is located proximal of the distal end of the main catheter body 16 . however , in alternative embodiments , the steerable portion 14 can extend to the distal end of the catheter main body 16 . curve directional arrows 74 show the potential direction of curvature for the steerable portion 14 in this embodiment . also shown is mandrel 22 extending through the main catheter body 16 to connect to the slider mechanism 32 , as described in u . s . pat . no . 6 , 178 , 354 , as cited above . [ 0030 ] fig9 is a partial cross section of the telescoping tip electrode catheter 10 showing the steering cables 70 and 72 and the steerable catheter portion 14 engaged in a curve 76 according to the fig1 a to 1 c embodiments . [ 0031 ] fig1 is a perspective view of the telescoping tip electrode catheter 10 with the steerable portion 14 engaged in a curve and the telescoping tip 20 being extended and contacting a treatment site 78 according to the fig1 a to 1 c embodiments . as a result of the curvature in the steerable portion 14 , additional pressure is applied to the electrode 20 to improve the contact between the electrode 20 and the treatment site 78 .
a medical device including a catheter and a telescoping mandrel with a tip electrode extending therethrough , the telescoping mandrel being moveable relative to the catheter shaft to extend from the catheter shaft distal end , thereby positioning the tip electrode at a distance from the catheter shaft distal end .