Band stop filter employing a capacitor and an inductor tank circuit to enhance MRI compatibility of active medical devices

摘要

A band stop filter is provided for a lead wire of an active medical device (AMD). The band stop filter includes a capacitor in parallel with an inductor. The parallel capacitor and inductor are placed in series with the lead wire of the AMD, wherein values of capacitance and inductance are selected such that the band stop filter is resonant at a selected frequency. The Q of the inductor may be relatively maximized and the Q of the capacitor may be relatively minimized to reduce the overall Q of the band stop filter to attenuate current flow through the lead wire along a range of selected frequencies. In a preferred form, the band stop filter is integrated into a TIP and/or RING electrode for an active implantable medical device.

主权项

1. An implantable lead, comprising:
a) at least one implantable lead wire extending from a proximal lead wire end to a distal lead wire portion having a distal lead wire end, wherein the proximal lead wire end is electrically connectable to electronic circuits of an implantable medical device; b) at least one electrode electrically connected to the distal lead wire portion or the distal lead wire end, wherein the electrode is configured to be placed in contact with biological cells inside a body; and c) a wound portion of the lead wire providing a self-resonant inductor disposed physically and electrically in series with the at least one electrode, d) wherein, along with a capacitive series resistance (Rc) and an inductor series resistance (RL), the self-resonant inductor has sufficient parasitic capacitance between adjacent turns of the wound lead wire so that at low frequencies of about 10 Hz to about 1 kHz, an inductive reactance and the inductor series resistance (RL) permit passage of biological signals from the electrode to the proximal lead wire end τ while a capacitive reactance and the capacitive series resistance (Rc) substantially act as an open circuit to the same biological signals that the inductive reactance and the inductor series resistance (RL) permit to pass, and e) wherein the capacitive series resistance (Rc) and the inductor series resistance (RL) provide a self-resonant inductor Q having a 3-dB bandwidth that is at least 100 kHz.