Mechanism for adjusting the exposed surface area and position of an electrode along a lead body

Abstract

An endocardial pacing and/or cardioversion/defibrillation lead having a plurality of electrodes and a mechanism for adjusting the exposed surface area of one or more electrode and/or the position and/or angular orientation of an electrode along a lead body. A fixed exposed, flexible, elongated commutator surface is provided extending along the lead body intermediate the proximal and distal lead body ends coupled by an electrical lead conductor extending to the proximal end of the lead body. A movable electrode assembly is provided that fits over and slides along the lead body, including the fixed commutator surface, that supports an exposed movable electrode on it. The movable electrode assembly includes at least one flexible, elongated, movable commutator surface within it that is electrically connected with the movable electrode. Electrical contact is established between the movable electrode and the lead connector end through contact of the fixed and movable commutator surfaces in a contact segment of contact area that varies with the relative movement of the movable contact surface with respect to the fixed contact surface. The position and exposed surface area of the movable electrode may be adjusted even further by use of a further electrode adjustable area outer insulating sheath positioned over the movable electrode assembly.

I claim: 
     
       1. An elongated implantable lead having a proximal lead end and a distal lead end comprising: an elongated lead body extending between said proximal lead end and said distal lead end;   a connector assembly located at the proximal end of said lead body;   a first electrical conductor having a proximal conductor end coupled with said connector assembly and extending through a proximal portion of said lead body to a distal conductor end;   an elongated outer lead sheath extending between said proximal and distal conductor ends for insulating said first electrical conductor through its length from body fluids and tissue;   means for providing an elongated, flexible, fixed commutator surface exposed to body fluids and tissue extending along said lead body;   means for coupling said elongated fixed commutator surface to said first electrical conductor distal to said proximal conductor end; and   a movable electrode assembly fitted over said fixed commutator surface adapted to be moved proximally and distally with respect to said fixed commutator surface and said elongated outer lead sheath, said movable electrode assembly further comprising:   an exposed, movable electrode supported by said movable electrode assembly;   means for defining a movable commutator surface within said movable electrode assembly adapted to be moved with movement of said movable electrode assembly while making contact with said fixed commutator surface in a contact segment;   means for electrically connecting said exposed, movable electrode with said movable commutator surface; and   means for electrically insulating said fixed commutator surface from exposure to body fluids and tissue.   
     
     
       2. The lead of claim 1, wherein said movable electrode is shaped in a band surface having a predetermined band width defining an electrode surface area, and further comprising: means for selectively insulating a portion of said electrode surface area to thereby vary the exposed surface area or position of the electrode.   
     
     
       3. The lead of claim 2, wherein said selectively insulating means further comprises a movable, tubular insulating sheath fitted over said movable electrode assembly and adapted to be moved proximally and distally with respect to said movable electrode and fixed at a selected position to expose a selected distal or proximal segment, respectively, of said exposed, movable electrode thereby varying the exposed surface area and position of the electrode. 
     
     
       4. The lead of claim 2, wherein said selectively insulating means further comprises a movable, tubular insulating sheath fitted over said movable electrode assembly having a window opening formed therein and adapted to be rotated about said movable electrode and be to fixed at a selected angular orientation with respect thereto expose a selected segment of the movable electrode, thereby allowing the angular orientation of the movable electrode to be adjusted. 
     
     
       5. The lead of claim 1, wherein said movable electrode is shaped in a band surface having a predetermined band width defining an electrode surface area, and further comprising: means for selectively varying said electrode exposed surface area or position.   
     
     
       6. The lead of claim 5, wherein said selectively varying means further comprises a movable, tubular insulating sheath fitted over said movable electrode assembly and adapted to be moved proximally and distally with respect to said movable electrode band surface and fixed at a selected position to expose a selected distal or proximal band segment, respectively, of said exposed, movable electrode thereby selectively varying said electrode surface area and position. 
     
     
       7. The lead of claim 5, wherein said selectively insulating means further comprises a movable, tubular insulating sheath fitted over said movable electrode assembly having a window opening formed therein and adapted to be rotated about said movable electrode and be to fixed at a selected angular orientation with respect thereto expose a selected segment of the movable electrode, thereby allowing the angular orientation of the movable electrode to be adjusted. 
     
     
       8. The lead of claim 1, wherein said fixed commutator surface is formed of a spiral wound conductor extending along said lead body to present a flexible conductive commutator surface. 
     
     
       9. The lead of claim 8, wherein said movable electrode assembly further comprises a tubular body having proximal and distal ends and a body lumen dimensioned to fit over said elongated outer lead sheath, wherein said movable commutator surface is formed as a further spiral wound conductor extending within said body lumen intermediate the proximal and distal ends thereof. 
     
     
       10. The lead of claim 1, wherein said movable electrode assembly further comprises a tubular body having a body lumen dimensioned to fit over said elongated outer lead sheath, and wherein said movable commutator surface is formed as a tubular, electrically conductive, surface within said body lumen. 
     
     
       11. The lead of claim 1, wherein said movable electrode assembly further comprises a tubular body having a body lumen dimensioned to fit over said elongated outer lead sheath and extends proximally to said connector assembly. 
     
     
       12. A method of adjusting the position of an electrode along the length of an elongated implantable lead having a proximal lead end and a distal lead end, the lead of the type comprising: an elongated lead body extending between said proximal lead end and said distal lead end;   a connector assembly located at the proximal end of said lead body;   a first electrical conductor having a proximal conductor end coupled with said connector assembly and extending through a proximal portion of said lead body to a distal conductor end; and   an elongated outer lead sheath extending between said proximal and distal conductor ends for insulating said first electrical conductor through its length from body fluids and tissue; the method further comprising the steps of:   providing an elongated, flexible, fixed commutator surface coupled to said first electrical conductor and extending along said lead body exposed to body fluids and tissue;   moving a movable electrode assembly fitted over said fixed commutator surface proximally and distally with respect to said fixed commutator surface, said movable electrode assembly bearing an exposed, movable electrode supported by said movable electrode assembly, a movable commutator surface within said movable electrode assembly adapted to be moved with movement of said movable electrode assembly while maintaining contact with said fixed commutator surface in a contact segment; and   fixing said movable electrode assembly in the selected position and electrically insulating said fixed commutator surface from body fluids and tissue.   
     
     
       13. The method of claim 12, wherein said movable electrode is shaped in a band surface having a predetermined band width defining an electrode surface area, and further comprising the step of: selectively insulating a portion of said electrode surface area to thereby vary the exposed surface area or position of the electrode.   
     
     
       14. The method of claim 13, wherein said selectively insulating step further comprises: fitting a movable, tubular insulating sheath over said movable electrode assembly;   moving said tubular insulating sheath proximally or distally with respect to said movable electrode to a selected position to expose a selected distal or proximal segment, respectively, of said exposed, movable electrode thereby varying the exposed surface area and position of the electrode; and   fixing said tubular insulating sheath in said selected position to electrically insulate the un-selected proximal or distal segment of said movable electrode from body fluids and tissues.   
     
     
       15. The method of claim 13, wherein said selectively insulating step further comprises: fitting a movable, tubular insulating sheath over said movable electrode assembly, said tubular insulating sheath having a window opening formed therein;   moving said tubular insulating sheath with respect to said movable electrode to a selected position to expose a selected window of said exposed, movable electrode thereby varying the exposed surface area and position of the electrode; and   fixing said tubular insulating sheath in said selected position to electrically insulate the un-selected proximal or distal segment of said movable electrode from body fluids and tissues.   
     
     
       16. The method of claim 13 wherein said moving step further comprises the step of: rotating said tubular insulating sheath about said movable electrode to a selected angular orientation of said window opening to orient said selected window of said exposed, movable electrode to a desired anatomical feature.   
     
     
       17. An elongated implantable lead having a proximal lead end and a distal lead end comprising: an elongated, tubular lead body extending between said proximal lead end and said distal lead end;   a connector assembly located at the proximal end of said lead body;   an electrical conductor having a proximal conductor end coupled with said connector assembly and extending through a proximal portion of said lead body to a distal conductor end proximal to said distal lead end;   an elongated, tubular outer lead sheath extending between said proximal and distal conductor ends for insulating said first electrical conductor through its length from body fluids and tissue having an outer lead sheath diameter;   an elongated inner lead sheath having a proximal sheath section extending within said outer lead sheath between said proximal conductor end and said distal conductor end and a distal sheath section extending from said distal conductor end to said distal end of said lead body;   a first wire conductor wound into an elongated exposed coil over said inner lead sheath and extending distally of said distal conductor end providing an elongated, flexible, fixed commutator surface of relatively constant commutator diameter extending along said lead body intermediate said proximal and distal ends thereof;   means for coupling said elongated exposed coil to said distal conductor end; and   a movable, tubular electrode assembly having an outer surface and an inner surface of an inner diameter for making sliding contact with said outer diameter of said outer lead sheath and said commutator diameter when moved over it, said tubular electrode assembly adapted to be moved proximally and distally with respect to said fixed commutator surface and over said elongated outer lead sheath to a selected position, said movable electrode assembly further comprising: an exposed electrode supported by the outer surface of said movable electrode assembly;   a second wire conductor wound into a second elongated exposed coil and positioned along said inner surface providing an elongated, flexible, movable commutator surface of relatively constant inner diameter for making contact with said fixed commutator surface in said contact segment;   means for electrically connecting said exposed electrode with said second wire conductor movable commutator surface; and   means for electrically insulating said coiled fixed commutator surface except for said contact segment.     
     
     
       18. The lead of claim 17, wherein said movable electrode assembly further comprises a tubular body having a body lumen dimensioned to fit over said elongated outer lead sheath and extends proximally to said connector assembly. 
     
     
       19. The lead of claim 17, wherein said movable electrode is shaped in a band surface having a predetermined band width defining an electrode surface area, and further comprising: means for selectively insulating a portion of said electrode surface area to thereby vary the exposed surface area or position of the electrode.   
     
     
       20. The lead of claim 19, wherein said selectively insulating means further comprises a movable, tubular insulating sheath fitted over said movable electrode assembly and adapted to be moved proximally and distally with respect to said movable electrode and fixed at a selected position to expose a selected distal or proximal segment, respectively, of said exposed, movable electrode thereby varying the exposed surface area and position of the electrode. 
     
     
       21. The lead of claim 19, wherein said selectively insulating means further comprises a movable, tubular insulating sheath fitted over said movable electrode assembly having a window opening formed therein and adapted to be rotated about said movable electrode and be to fixed at a selected angular orientation with respect thereto expose a selected segment of the movable electrode, thereby allowing the angular orientation of the movable electrode to be adjusted. 
     
     
       22. The lead of claim 17, wherein said movable electrode is shaped in a band surface having a predetermined band width defining an electrode surface area, and further comprising: means for selectively varying said electrode exposed surface area or position.   
     
     
       23. The lead of claim 22, wherein said selectively varying means further comprises a movable, tubular insulating sheath fitted over said movable electrode assembly and adapted to be moved proximally and distally with respect to said movable electrode band surface and fixed at a selected position to expose a selected distal or proximal band segment, respectively, of said exposed, movable electrode thereby selectively varying said electrode surface area and position. 
     
     
       24. The lead of claim 22, wherein said selectively insulating means further comprises a movable, tubular insulating sheath fitted over said movable electrode assembly having a window opening formed therein and adapted to be rotated about said movable electrode and be to fixed at a selected angular orientation with respect thereto expose a selected segment of the movable electrode, thereby allowing the angular orientation of the movable electrode to be adjusted. 
     
     
       25. The lead of claim 17, wherein said fixed commutator surface is formed of a spiral wound conductor extending along said lead body to present a flexible conductive commutator surface. 
     
     
       26. The lead of claim 25, wherein said movable electrode assembly further comprises a tubular body having proximal and distal ends and a body lumen dimensioned to fit over said elongated outer lead sheath, wherein said movable commutator surface is formed as a further spiral wound conductor extending within said body lumen intermediate the proximal and distal ends thereof. 
     
     
       27. The lead of claim 17, wherein said movable electrode assembly further comprises a tubular body having a body lumen dimensioned to fit over said elongated outer lead sheath, and wherein said movable commutator surface is formed as a tubular, electrically conductive, surface within said body lumen.