Electromagnetic shield for a passive electronic component in an active medical device implantable lead

摘要

A shielded component or network for an active medical device (AMD) implantable lead includes an implantable lead having a length extending from a proximal end to a distal end, all external of an AMD housing, a passive component or network disposed somewhere along the length of the implantable lead, the passive component or network including at least one inductive component having a first inductive value, and an electromagnetic shield substantially surrounding the inductive component or the passive network. The first inductive value of the inductive component is adjusted to account for a shift in its inductance to a second inductive value when shielded.

主权项

1. An implantable lead, comprising:
a) a lead body having an axial length extending from a proximal lead end to a distal lead end, where the proximal lead end is configured to be permanently or removably connectable to an active implantable medical device; b) a tip electrode configured to be contactable with biological cells, where the tip electrode is disposed at or adjacent to the distal lead end; c) a first conductor disposed within the lead body, the first conductor electrically coupled to the tip electrode and extending to or adjacent to the proximal lead end, wherein the first conductor comprises an insulated and self-resonant first inductive coil, where the first inductive coil is disposed physically and electrically in series with the first conductor, and where the first inductive coil is disposed proximal to the tip electrode in relation to the axial length of the lead body, wherein the first inductive coil comprises a first parasitic capacitance between its adjacent turns creating a first total capacitance wherein a first equivalent electrical circuit schematic comprises a first inductance in parallel with the first total capacitance and wherein the first inductive coil is self-resonant at or near an MRI RF pulsed frequency and presents a high impedance in series with the first conductor providing at least 10 dB of attenuation at its resonant center frequency, wherein the first inductive coil has a first overall circuit Q wherein the resultant 3 dB bandwidth is at least 100 kHz; d) a ring electrode configured to be contactable with biological cells, where the ring electrode is disposed near the distal lead end and proximal to the first inductive coil in relation to the axial length of the lead body; e) a second conductor disposed within the lead body and insulated from the first conductor, the second conductor electrically coupled to the ring electrode and extending to or adjacent to the proximal lead end, wherein the second conductor comprises an insulated and self-resonant second inductive coil, where the second inductive coil is disposed physically and electrically in series with the second conductor, and where the second inductive coil is disposed proximal to the ring electrode in relation to the axial length of the lead body, wherein the second inductive coil comprises a second parasitic capacitance between its adjacent turns creating a second total capacitance wherein a second equivalent electrical circuit schematic comprises a second inductance in parallel with the second total capacitance and wherein the second inductive coil is self-resonant at or near an MRI RF pulsed frequency and presents a high impedance in series with the second conductor providing at least 10 dB of attenuation at its resonant center frequency, wherein the second inductive coil has a second overall circuit Q wherein the resultant 3 dB bandwidth is at least 100 kHz; and f) a first electromagnetic shield at least partially surrounding the first inductive coil.