Mri compatible tachycardia lead

Abstract

A medical device lead includes a proximal connector configured to couple the lead to a pulse generator, an insulative lead body extending distally from the proximal connector, and a conductor assembly extending distally from the proximal connector within the lead body. The conductor assembly includes a conductor having a proximal end electrically coupled to the connector and a distal end electrically coupled to a defibrillation coil. A first portion of the defibrillation coil is exposed at an outer surface of the medical device lead and a second portion of the defibrillation coil is insulated at the outer surface of the medical device lead.

We claim: 
     
         1 . A medical device lead comprising:
 a proximal connector configured to couple the lead to a pulse generator;   an insulative lead body extending distally from the proximal connector;   a conductor assembly extending distally from the proximal connector within the lead body and including a conductor having a proximal end electrically coupled to the connector and a distal end electrically coupled to a defibrillation coil, wherein a first portion of the defibrillation coil is exposed at an outer surface of the medical device lead and a second portion of the defibrillation coil is insulated at the outer surface of the medical device lead, wherein opposing ends of the first portion of defibrillation coil are short circuited.   
     
     
         2 . The medical device lead of  claim 1 , wherein the defibrillation coil is unifilar. 
     
     
         3 . The medical device lead of  claim 1 , wherein the conductor comprises a conductive cable. 
     
     
         4 . The medical device lead of  claim 3 , wherein the conductor further comprises one or more conductive coils in series with the conductive cable. 
     
     
         5 . The medical device lead of  claim 4 , wherein the conductor comprises two or more conductive coils in series with the conductive cable, and wherein a length of the conductive cable between adjacent conductive coils is less than one quarter wavelength of a signal carried by the conductive assembly. 
     
     
         6 . The medical device lead of  claim 1 , wherein the conductive assembly and the second portion have a total DC resistance of less than about 5 Ω. 
     
     
         7 . A medical device lead comprising:
 a first connector configured to couple the lead to a pulse generator;   an insulative lead body extending distally from the first connector;   a first conductor extending distally from the first connector within the lead body and having a proximal end electrically coupled to the first connector;   a first defibrillation coil exposed at an outer surface of the medical device lead; and   a first high impedance coil connected between the first conductor and the first defibrillation coil, wherein the first high impedance coil is insulated at the outer surface of the medical device lead and has an impedance greater than the first conductor, wherein opposing ends of the first defibrillation coil are short circuited.   
     
     
         8 . The medical device lead of  claim 7 , wherein the first defibrillation coil is unifilar. 
     
     
         9 . The medical device lead of  claim 7 , wherein the first conductor comprises a conductive cable. 
     
     
         10 . The medical device lead of  claim 9 , wherein the first conductor further comprises one or more conductive coils in series with the conductive cable. 
     
     
         11 . The medical device lead of  claim 10 , wherein the first conductor comprises two or more conductive coils in series with the first conductive cable, and wherein a length of the first conductive cable between adjacent conductive coils is less than one quarter wavelength of a signal carried by the first conductor. 
     
     
         12 . The medical device lead of  claim 7 , wherein the first high impedance coil and the first conductor have a total DC resistance of less than about 5 Ω. 
     
     
         13 . The medical device lead of  claim 7 , and further comprising:
 a second connector configured to couple the lead to the pulse generator;   a second conductor having a proximal end electrically coupled to the second connector;   a second defibrillation coil exposed at an outer surface of the medical device lead; and   a second high impedance coil connected between the conductor and the defibrillation coil, wherein the second high impedance coil is insulated at the outer surface of the medical device lead and has an impedance greater than the second conductor.   
     
     
         14 . The medical device lead of  claim 13 , wherein opposing ends of the second defibrillation coil are short circuited. 
     
     
         15 . A medical device lead comprising:
 one or more proximal connectors each configured to couple to a pulse generator;   an insulative lead body extending distally from the one or more proximal connectors;   one or more conductors each extending distally from and electrically connected to one of the one or more proximal connectors; and   one or more defibrillation coils each connected to a distal end of one of the one or more conductors, wherein a first portion of each defibrillation coil is exposed at an outer surface of the medical device lead and a second portion of each defibrillation coil is insulated at the outer surface of the medical device lead, wherein opposing ends of at least one of the one or more defibrillation coils are short circuited.   
     
     
         16 . The medical device lead of  claim 15 , wherein at least one of the one or more defibrillation coils is unifilar. 
     
     
         17 . The medical device lead of  claim 15 , wherein the one or more defibrillation coils consists of a plurality of defibrillation coils, and for each of the defibrillation coils, the opposing ends of the defibrillation coil are short circuited. 
     
     
         18 . The medical device lead of  claim 15 , wherein each of the one or more conductors comprises a conductive cable. 
     
     
         19 . The medical device lead of  claim 18 , wherein at least one of the one or more conductors further comprises one or more conductive coils in series with the conductive cable. 
     
     
         20 . The medical device lead of  claim 19 , wherein the at least one of the one or more conductors comprises two or more conductive coils in series with the conductive cable, and wherein a length of the conductive cable between adjacent conductive coils is less than one quarter wavelength of a signal carried by the conductor.