Methodology and apparatus to terminate abandoned active implantable medical device leads

Abstract

An energy management system facilitates the transfer of high frequency energy coupled into an implanted abandoned lead at a selected RF frequency or frequency band, to an energy dissipating surface. This is accomplished by conductively coupling the implanted abandoned lead to the energy dissipating surface of an abandoned lead cap through an energy diversion circuit including one or more passive electronic network components whose impedance characteristics are at least partially tuned to the implanted abandoned lead's impedance characteristics.

What is claimed is: 
     
         1 . A system for terminating an abandoned implanted lead to minimize heating in a high power electromagnetic field environment, comprising:
 an implanted abandoned lead having a proximal end and a distal end, and impedance characteristics at a selected RF frequency or frequency band;   an abandoned lead cap associated with the proximal end of the implanted abandoned lead, comprising an energy dissipating surface and a housing in which the proximal end of the implanted lead is disposed; and   an energy diversion circuit conductively coupling the implanted abandoned lead to the energy dissipating surface to facilitate transfer to the energy dissipating surface of high frequency energy induced on the implanted abandoned lead at the selected RF frequency or frequency band.   
     
     
         2 . The system of  claim 1 , wherein the energy diversion circuit comprises one or more passive electronic network components whose impedance characteristics are at least partially tuned to the implanted abandoned lead's impedance characteristics. 
     
     
         3 . The system of  claim 2 , wherein the selected RF frequency or frequency band comprises an MRI frequency. 
     
     
         4 . The system of  claim 2 , wherein the energy diversion circuit has a reactance and is vectorially opposite to the characteristic reactance of the implanted lead. 
     
     
         5 . The system of  claim 2 , wherein the energy diversion circuit has a capacitive reactance generally equal and opposite to the characteristic inductive reactance of the implanted lead. 
     
     
         6 . The system of  claim 2 , wherein the energy diversion circuit comprises at least one series resonant LC trap filter. 
     
     
         7 . The system of  claim 2 , wherein the energy dissipating surface comprises convolutions or fins, for increasing the surface area thereof. 
     
     
         8 . The system of  claim 2 , wherein the energy dissipating surface comprises a plurality of spaced-apart energy dissipating surfaces. 
     
     
         9 . The system of  claim 2 , wherein the energy diversion circuit includes at least one non-linear circuit element. 
     
     
         10 . The system of  claim 2 , wherein the energy diversion circuit comprises a high pass filter. 
     
     
         11 . The system of  claim 10 , wherein the high pass filter prevents low frequency gradient field-induced energy in the implanted lead or the leadwire from passing through the diversion circuit to the energy dissipating surface. 
     
     
         12 . The system of  claim 10 , wherein the high pass filter comprises a capacitor. 
     
     
         13 . The system of  claim 1 , wherein the energy diversion circuit comprises a short to the energy dissipating surface. 
     
     
         14 . The system of  claim 1 , including an RFID tag associated with the abandoned lead cap. 
     
     
         15 . The system of  claim 1 , wherein the energy dissipating surface comprises grade 5 or grade 23 titanium. 
     
     
         16 . The system of  claim 1 , wherein the energy dissipating surface includes one or more slots for reducing eddy current heating therein. 
     
     
         17 . The system of  claim 1 , wherein the proximal end of the implanted abandoned lead comprises an IS-1, IS-4 or DF-1 connector. 
     
     
         18 . The system of  claim 1 , wherein the energy diversion circuit comprises at least one discrete electronic network component taken from the group of an inductor, a capacitor, a resistor, a diode, or a pin diode. 
     
     
         19 . The system of  claim 1 , wherein the abandoned lead cap housing includes a seal which engages the lead to isolate the proximal end of the implanted abandoned lead from body fluid. 
     
     
         20 . The system of  claim 1 , wherein the energy dissipating surface comprises a material capable of being visualized during a magnetic resonance scan.