STIMULATION SYSTEM, IN PARTICULAR A CARDIAC PACEMAKER

• US 20090024180A1
• Filed: 07/11/2008
• Published: 01/22/2009
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: Universitat Duisburg-Essen
• Original Assignee: Universitat Duisburg-Essen
• Inventors: KISKER, Erhard, WIENEKE, Heinrich
• Granted Patent: US 8,321,021 B2
• Time in Patent Office: Days
• US Class Current: 607/32
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

A stimulation system, an implantable electrode device and a method for operating an implantable electrode device are proposed. A simplified implantation, a simple construction and reliable control are made possible by the electrode device being supplied with energy, and controlled, in an exclusively wireless manner via a time-variable magnetic field. The magnetic field is generated by an implanted control device.

Claims

1. A stimulation system, in particular a cardiac pacemaker, comprising an implantable control device and an implantable electrode device for generating electrical impulses, which can be supplied with energy and/or controlled by the control device in an exclusively wireless manner by means of a time-varying magnetic field, the control device being configured such that the field strength of the magnetic field, at least during switch-on times, has a substantially ramp- or sawtooth-shaped time profile or is bipolar or pulsed.

2. The stimulation system according to claim 1, wherein the control device is configured such that the magnetic field is generated intermittently and/or wherein the control device is configured such that the magnetic field has a switch-on ratio of less than 0.5, in particular less than 0.25, particularly preferably substantially 0.1 or less.

3. The stimulation system according to claim 1, wherein the control device is configured in such a manner that the magnetic field is alternately generated with an opposite field direction for the alternate generation of an electrical impulse and activating the electrode device before generating the next electrical impulse, in particular wherein the activation takes place shortly before generation of the next electrical impulse.

4. The stimulation system according to claim 1, wherein the frequency of the magnetic field is less than 3 Hz, in particular corresponds to the desired frequency of the electrical impulses to be generated.

5. The stimulation system according to claim 1, wherein the stimulation system is configured in such a manner that in the switched-on state the magnetic field is formed by a plurality of unipolar or bipolar magnetic field pulses and/or that the respective switch-on duration of the magnetic field controls or determines the length of each electrical impulse of a stimulation generated by the electrode device and/or the magnetic field is utilized for energy recovery.

6. The stimulation system according to claim 1, wherein the control device is configured in such a manner that the field strength of the magnetic field in the region of the electrode device is substantially 1 to 20 mT, in particular 2 to 10 mT.

7. The stimulation system according to claim 1, wherein the control device in the implanted state can be charged inductively from outside.

8. An implantable electrode device for a stimulation system, specifically a cardiac pacemaker, for generating electrical impulses, wherein the electrode device is configured as a wireless and/or compact structural unit and can be supplied with energy and directly controlled exclusively by means of a varying magnetic field, the electrode device comprising only passive components and a rectifier.

9. The electrode device according to claim 8, wherein the electrode device is configured in such a manner that an electrical impulse is only generated when a first minimum field strength of the magnetic field is exceeded, preferably wherein the electrode device is configured in such a manner that it generates and delivers an electrical impulse each time the minimum field strength is exceeded, preferably only after a respective preceding activation.

10. The electrode device according to claim 9, wherein the electrode device is configured in such a manner that an electrical impulse can be generated in each case only following previous activation, in particular by exceeding a second minimum field strength of the magnetic field having the opposite field direction to the field direction for the generation of an electrical impulse, in particular wherein the second minimum field strength is greater than the first minimum field strength.

11. The electrode device according to claim 10, wherein the minimum field strength is substantially 0.5 to 20 mT, in particular 1 to 10 mT.

12. The electrode device according to claim 8, wherein the electrode device comprises a coil device which generates a pulse-like induction voltage when a first minimum field strength of the magnetic field is exceeded, in particular wherein the coil device has a coil core or a core element having a magnetization which varies abruptly depending on the acting magnetic field strength and/or having an, in particular, wire-like layer arrangement of soft and hard magnetic material.

13. The electrode device according to claim 8, wherein the electrode device comprises a coil device, wherein an electrical impulse having a voltage of at least 0.5 V and a time duration of at least 0.05 ms can be generated by the coil device by an external and/or varying magnetic field having a field strength in the region of the electrode device of at most 10 mT, in particular substantially 2 mT or less and/or wherein the coil device comprises at least 1,000 turns.

14. The electrode device according to claim 8, wherein the electrode device preferably comprises only a passively operating pulse forming device, in particular having an inductance, a capacitance and/or a resistance, and/or that the electrode device is configured as battery-less and/or amplifier-less, and/or that the electrode device comprises a coil device with a magnetic core, the core being magnetically soft or ultra-soft.

15. The electrode device according to claim 8, wherein the electrode device is configured such that each pulse-like induction voltage is output as an electrical impulse, in particular, via integrated electrodes.

16. An implantable stimulation device for a stimulation system, in particular a cardiac pacemaker, for electrical stimulation, wherein the stimulation device can be exclusively supplied with energy and in particular controlled by means of an external and/or varying magnetic field and/or wherein the stimulation device comprises a magnetisable, preferably coil-free element whose magnetization and magnetic leakage flux can be varied by variation of the magnetic field for indirect, in particular electrode-less electrical stimulation.

17. The stimulation device according to claim 16, wherein the element is ferromagnetic or has a magnetization which varies abruptly depending on the acting magnetic field strength.

18. The stimulation device according to claim 16, wherein the element comprises an, in particular, wire-like layer arrangement of soft and hard-magnetic material.

19. A method for operating an implantable electrode device, in particular a cardiac pacemaker for generating electrical impulses, wherein the electrode device is supplied with energy and directly controlled by means of a magnetic field to generate the electrical impulses, wherein the magnetic field in the switched-on state is formed by a plurality of unipolar or bipolar magnetic field pulses and that the respective switch-on time of the magnetic field controls or determines the length of the electrical impulse respectively generated by the electrode device or during a contiguous sequence of electrical impulses.

20. The method according to claim 19, wherein the number of magnetic field impulses is varied for variation of the duration of each electrical impulse or a contiguous sequence of electrical impulses and/or that the magnetic impulses have a substantially sawtooth-shaped profile.

21. The method according to claim 19, wherein the field strength of the magnetic field, at least during switch-on times, has a substantially ramp- or sawtooth-shaped time profile.

22. The method according to claim 19, wherein the magnetic field has a switch-on ratio of less than 0.5, in particular less than 0.25, particularly preferably substantially 0.1 or less.

23. A method for generating an electrical impulse in tissue, in particular for operating a cardiac pacemaker, wherein the magnetization of a magnetisable, preferably ferromagnetic element is varied by an external or varying magnetic field in order to vary the magnetic leakage flux of the element for direct electrical stimulation or generation of the electrical impulse.

24. A stimulation system, in particular a cardiac pacemaker, comprising an implantable control device and an implantable electrode device for generating electrical impulses, which can be supplied with energy and/or controlled by the control device in an exclusively wireless manner by means of a time-varying magnetic field, at least one of the control device and electrode device comprising a flexible housing.