TANK FILTERS PLACED IN SERIES WITH THE LEAD WIRES OR CIRCUITS OF ACTIVE MEDICAL DEVICES TO ENHANCE MRI COMPATIBILITY

• US 20110213233A1
• Filed: 04/06/2011
• Published: 09/01/2011
• Est. Priority Date: 06/08/2006
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Frysz, Christine, Dabney, Warren S., Brendel, Richard L., Stevenson, Robert A.
• Granted Patent: US 8,649,857 B2
• Time in Patent Office: Days
• US Class Current: 600/373
• CPC Class Codes: A61B 2562/18 Shielding or protection of sensors from environmental influences, e.g. protection from mechanical damage
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3754 Feedthroughs

Abstract

A TANK filter is provided for a lead wire of an active medical device (AMD). The TANK 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 TANK 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 TANK filter to attenuate current flow through the lead wire along a range of selected frequencies. In a preferred form, the TANK filter is integrated into a TIP and/or RING electrode for an active implantable medical device.

Claims

1-93. -93. (canceled)

94. An implantable medical therapeutic or diagnostic device, comprising:

an active medical device including electronic circuitry for therapy delivery or detection of biological signals, an electrode and an at least partially coiled lead wire for connecting the electrode to the electronic circuitry; and

a capacitor disposed within a coiled portion of the lead wire, the lead wire being conductively coupled to the capacitor to form a tank filter having electrical inductance in parallel with capacitance;

wherein the tank filter attenuates current flow over a range of selected frequencies.

95. The device of claim 94, wherein the capacitor comprises a chip capacitor having a first set of electrode plates conductively coupled to a first metallization surface, and a second set of electrode plates conductively coupled to a second metallization surface, and wherein the lead wire is conductively coupled to the capacitor'"'"'s first and second metallization surfaces.

96. The device of claim 94, wherein the tank filter has an overall circuit Q resulting in a 3 dB bandwidth on the order of MHz.

97. The device of claim 94, wherein the range of selected frequencies comprise MRI RF pulsed frequencies.

98. The device of claim 94, wherein the capacitor is comprised of biocompatible materials.

99. The device of claim 94, wherein the active medical device comprises a bipolar pacemaker having the lead wire connected to a cardiac TIP electrode and a second lead wire connected to a RING electrode.

100. The device of claim 99, wherein the tank filter is formed with the first lead wire, the second lead wire, or both.

101. A medical therapeutic or diagnostic device, comprising:

an active medical device including electronic circuitry for therapy delivery or detection of biological signals, an electrode and an at least partially coiled lead wire for connecting the electrode to the electronic circuitry; and

a chip capacitor disposed within a coiled portion of the lead wire, the capacitor having a first set of electrode plates conductively coupled to a first metallization surface, and a second set of electrode plates conductively coupled to a second metallization surface;

wherein the lead wire is conductively coupled to the first and second metallization surfaces of the capacitor to form a tank filter having electrical inductance in parallel with capacitance; and

wherein the tank filter has an overall circuit Q resulting in a 3 dB bandwidth on the order of MHz such that the tank filter attenuates current flow over a range of selected frequencies.

102. The device of claim 101, wherein the range of selected frequencies comprise MRI RF pulsed frequencies.

103. The device of claim 101, wherein the capacitor is comprised of biocompatible materials.

104. The device of claim 101, wherein the active medical device comprises a bipolar pacemaker having the lead wire connected to a cardiac TIP electrode and a second lead wire connected to a RING electrode.

105. The device of claim 104, wherein the tank filter is formed with the first lead wire, the second lead wire, or both.

106. An implantable medical therapeutic or diagnostic device, comprising:

a bipolar pacemaker including electronic circuitry for therapy delivery or detection of biological signals, a first lead wire connected to a cardiac TIP electrode and the electronic circuitry, and a second lead wire connected to a RING electrode and the electronic circuitry; and

a chip capacitor comprised of biocompatible materials disposed within a coiled portion of the first or second lead wire, the capacitor having a first set of electrode plates conductively coupled to a first metallization surface, and a second set of electrode plates conductively coupled to a second metallization surface;

wherein the first or second lead wire is conductively coupled to the first and second metallization surfaces of the capacitor to form a tank filter having electrical inductance in parallel with capacitance; and

wherein the tank filter has an overall circuit Q resulting in a 3 dB bandwidth on the order of MHz such that the tank filter attenuates current flow over a range of selected MRI RF pulsed frequencies.