Extracorporeal Unit for Inspecting the Insulation of an Electrical Wire of an Implanted Medical Device

• US 20130310887A1
• Filed: 09/07/2012
• Published: 11/21/2013
• Est. Priority Date: 05/18/2012
• Status: Active Grant

• Current Assignee: Guy P. Curtis And Frances L. Curtis Trust
• Original Assignee: Guy P. Curtis And Frances L. Curtis Trust
• Inventors: Curtis, Guy P.
• Granted Patent: US 10,232,184 B2
• Time in Patent Office: Days
• US Class Current: 607/5
• CPC Class Codes: A61B 2560/0276 Determining malfunction
• CPC Class Codes: A61B 5/276 Protection against electrode failure
• CPC Class Codes: A61B 5/29 for permanent or long-term implantation
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/371 Capture, i.e. successful stimulation
• CPC Class Codes: A61N 1/3943 for threshold determination
• CPC Class Codes: G01R 31/1227 of components, parts or materials G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16

Abstract

A system is provided for testing the electrical integrity of an implanted pacemaker or defibrillator lead. The system includes a container holding an electrically conductive solution, such as a saline solution. A voltage source and two electrodes are provided to pass an electrical current through the solution. To use the system, the proximal end of the electrical lead is disconnected from the implanted electronic device, passed through the saline solution and then electrically connected to a device/monitor. During testing, the device/monitor sends a test pulse through the lead and monitors electrical activity in the lead. To test sequential locations along the length of the proximal segment, the segment is drawn through the saline solution and between the electrodes while test pulses are sent and monitored. The monitor detects abnormal electrical activity in the lead indicative of a break in lead insulation.

Claims

1. A system for testing the electrical integrity of an elongated lead when the lead is used with an implanted electronic device to stimulate/control heart muscle activity of a patient, wherein the elongated lead defines an axis and has insulated electrode wires extending between a proximal end and a distal end of the lead to establish an electrical connection between the electronic device and the heart muscle of the patient, the system comprising:

a monitor selectively connected to the proximal end of the lead for monitoring electrical activity in the lead;

an electrically conductive solution positioned to surround at least a portion of said lead; and

a voltage source having a cathode and an anode, the anode and cathode positioned to establish an electrical current through the solution and cause an interrupt signal that is received by the monitor when there is a break in the insulation of the lead.

2. A system as recited in claim 1 wherein the electrically conductive solution is a saline solution.

3. A system as recited in claim 1 wherein the electrode wires are cylindrically shaped and are coaxially aligned along the axis of the electrical lead.

4. A system as recited in claim 3 wherein the electrode wires of the electrical lead include an outer electrode wire and an inner electrode wire, and the monitor is electronically connected to the respective electrode wires of the electrical lead at the proximal end of the electrical lead.

5. A system as recited in claim 1 wherein the electrical lead is operationally implanted in the body of the patient to establish a distal segment of the electrical lead extending between a tie-down point to the heart muscle, and a proximal segment of the electrical lead extending between the electronic device and the tie-down point, and wherein the system tests the proximal segment of the electrical lead while the distal segment remains substantially undisturbed.

6. A system as recited in claim 5 wherein the proximal segment of the electrical lead includes an excess portion of the lead to provide for a required flexibility of the proximal segment, arid wherein the excess portion is implanted in a subcutaneous pocket between the electronic device and the tie-down point.

7. A system as recited in claim 1 wherein the electronic device is selected from a group of electronic devices consisting of a pacemaker pulse generator and a defibrillator pulse generator.

8. A system as recited in claim 1 further comprising a device connected to the proximal end of the lead for sending a test pulse through the lead and wherein the anode and cathode are positioned to establish an electrical current through the solution and cause an interrupt signal to be received by the monitor to indicate a defective lead when a break in the insulation of the lead causes the current in the solution to interfere with the test pulse from the device.

9. A system as recited in claim 1 further comprising a container having a wall surrounding a chamber for holding the electrically conductive solution therein with the cathode and the anode respectively connected to the wall of the container and wherein an access port is formed in the wall of the container for passing the lead through the solution.

10. A system as recited in claim 1 wherein the electrically conductive solution is disposed within a subcutaneous pocket of the patient.

11. A system as recited in claim 1 further comprising a retractor having a non-conductive tip, and with the anode and cathode disposed on the non-conductive retractor tip for insertion into the electrically conductive solution.

12. A system as recited in claim 11 wherein the tip of the retractor is L-shaped to align the anode and cathode in a direction substantially parallel to a plane containing a portion of the lead.

13. A system for testing the integrity of insulation in a proximal segment of an electrical lead while a distal segment of the lead remains attached to a patient'"'"'s heart, the system comprising:

a voltage source having a cathode and an anode;

an electrically conductive fluid surrounding at least a portion of the proximal segment of the lead, the fluid electrically connected to the cathode and anode to establish an electrical current through the fluid; and

a monitoring circuit connected to the lead and configured to output an alarm signal in response to an input from the lead indicating that the current in the fluid is generating an interrupt signal in the lead due to an insulation breach.

14. A system as recited in claim 13 further comprising a pulse generator connected to a proximal end of the lead for sending a test pulse through the lead with the monitoring circuit connected to the lead and configured to output an alarm signal in response to an input from the lead indicating that the current in the fluid is generating an interrupt signal in the lead interfering with the test pulse from the pulse generator due to an insulation breach.

15. A system as recited in claim 14 wherein the test pulse is above a capture threshold necessary to stimulate heart chamber contraction,

16. A system as recited in claim 14 wherein the test pulse has a pulse duration in the range of approximately 0.4 ms to 0.5 ms.

17. A system as recited in claim 13 wherein the voltage source produces a pulsed current in the electrically conductive fluid.

18. A system as recited in claim 17 wherein the pulsed current has a pulse duration in the range of approximately 1 ms to 2 ms.

19. A system as recited in claim 13 further comprising a container for holding the fluid, the container formed with an access port for passing the lead into the container and through the fluid.

20. A system as recited in claim 13 wherein the lead is a bipolar pacemaker lead.

21. A method for testing the integrity of insulation in a proximal segment of an electrical lead while a distal segment of the lead remains attached to a patients heart, the method comprising the steps of:

surrounding at least a portion of the proximal segment of the lead with an electrically conductive fluid;

passing an electrical current through the fluid;

monitoring an output from the lead; and

generating an alarm signal in response to an input from the lead indicating that the current in the fluid is generating an interrupt signal in the lead due to an insulation breach.

22. A method as recited in claim 21 further comprising the step of connecting a pulse generator to a proximal end of the lead and sending a test pulse through the lead and wherein the alarm signal is generated in response to an output from the lead indicating that the current in the fluid is interfering with the test pulse from the pulse generator due to an insulation defect.

23. A method as recited in claim 21 wherein the passing step is performed while a distal end of the lead is attached to a patient'"'"'s heart.

24. A method as recited in claim 21 wherein only a portion of the proximal segment of the lead is surrounded by the fluid at a time and further comprising the step of passing the proximal segment of the lead through the fluid to sequentially surround a plurality of proximal segment portions with the fluid.

25. A method as recited in claim 21 wherein the surrounding step is accomplished using a container formed with an access port.