Rate responsive leadless cardiac pacemaker

• US 20070088400A1
• Filed: 10/13/2006
• Published: 04/19/2007
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Nanostim, Inc (Abbott Laboratories)
• Inventors: Jacobson, Peter
• Granted Patent: US 7,937,148 B2
• Time in Patent Office: Days
• US Class Current: 607/21
• CPC Class Codes: A61M 25/0662 Guide tubes
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/0573 chacterised by means penetrating the heart tissue, e.g. helix needle or hook
• CPC Class Codes: A61N 1/0587 Epicardial electrode systems; Endocardial electrodes piercing the pericardium
• CPC Class Codes: A61N 1/059 Anchoring means
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371
• CPC Class Codes: A61N 1/3708 for power depletion
• CPC Class Codes: A61N 1/372 Arrangements in connection with the implantation of stimulators
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile
• CPC Class Codes: A61N 1/37252 Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: A61N 1/37288 : Communication to several implantable medical devices within one patient
• CPC Class Codes: A61N 1/37512 : Pacemakers
• CPC Class Codes: A61N 1/37518 : Anchoring of the implants, e.g. fixation
• CPC Class Codes: A61N 1/3756 : Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 1/3925 : Monitoring; Protecting
• CPC Class Codes: A61N 1/3956 : Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/39622 : Pacing therapy
• CPC Class Codes: A61N 2001/058 : Fixing tools
• CPC Class Codes: H04B 13/005 : Transmission systems in which the medium consists of the human body

Abstract

A leadless cardiac pacemaker comprises a housing, a plurality of electrodes coupled to an outer surface of the housing, and a pulse delivery system hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse delivery system configured for sourcing energy internal to the housing, generating and delivering electrical pulses to the electrode plurality. The pacemaker further comprises an activity sensor hermetically contained within the housing and adapted to sense activity and a processor hermetically contained within the housing and communicatively coupled to the pulse delivery system, the activity sensor, and the electrode plurality, the processor configured to control electrical pulse delivery at least partly based on the sensed activity.

Claims

1. A pacemaker comprising:

the pacemaker configured as a leadless cardiac pacemaker comprising;

a housing;

a plurality of electrodes coupled to the housing;

a pulse delivery system hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse delivery system configured for sourcing energy internal to the housing, generating and delivering electrical pulses to the electrode plurality;

an activity sensor hermetically contained within the housing and adapted to sense activity; and

a processor hermetically contained within the housing and communicatively coupled to the pulse delivery system, the activity sensor, and the electrode plurality, the processor configured to control electrical pulse delivery at least partly based on the sensed activity.

2. The pacemaker according to claim 1 further comprising:

the plurality of electrodes coupled on, within, or within two centimeters of the housing.

3. The pacemaker according to claim 1 further comprising:

the processor that controls electrical pulse delivery and application of the activity sensor according to at least one programmable parameter, the processor being programmable by communication signals transmitted via the electrode plurality.

4. The pacemaker according to claim 1 further comprising:

the activity sensor adapted for controlling rate-responsive pacing and selected from a group consisting of an accelerometer, a temperature sensor, and a pressure sensor.

5. The pacemaker according to claim 1 further comprising:

the activity sensor comprising an accelerometer and accelerometer amplifier configured to detect patient activity for rate-responsive pacing.

6. The pacemaker according to claim 4 further comprising:

the processor configured to sample signals from the accelerometer synchronously with a cardiac cycle determined by the pulse delivery system, compare acceleration signals acquired at relative times in multiple cardiac cycles, and distinguishes acceleration signals resulting from activity from signals resulting from cardiac wall motion.

7. The pacemaker according to claim 1 further comprising:

the activity sensor comprising a temperature transducer, the temperature transducer comprising a thermistor and a signal conditioning amplifier connected to the processor.

8. The pacemaker according to claim 1 further comprising:

the activity sensor comprising a pressure transducer and a signal conditioning amplifier connected to the processor.

9. The pacemaker according to claim 1 further comprising:

the activity sensor that operates with a power requirement of no more than 10 microwatts.

10. The pacemaker according to claim 1 further comprising:

the pulse delivery system configured for generating and delivering electrical energy with the stimulation pulse interrupted by at least one notch that conveys information to a device external to the pacemaker, the conveyed information comprising data selected from a group consisting of programmable parameter settings, event counts, power-supply voltage, power-supply current, rate-response control parameters adapted for converting an activity sensor signal to a rate-responsive pacing parameter.

11. The pacemaker according to claim 1 further comprising:

the pulse delivery system configured for generating and delivering electrical energy with the stimulation pulse that conveys information to a device external to the pacemaker in designated codes encoding the information in pacing pulse width, the conveyed information comprising data selected from a group consisting of programmable parameter settings, event counts, power-supply voltage, power-supply current, rate-response control parameters adapted for converting an activity sensor signal to a rate-responsive pacing parameter.

12. The pacemaker according to claim 1 further comprising:

the pulse delivery system configured for generating and delivering electrical energy with the stimulation pulse that conveys information to a device external to the pacemaker in designated codes encoding the information in modulation of off-time between pacing pulses, the conveyed information comprising data selected from a group consisting of programmable parameter settings, event counts, power-supply voltage, power-supply current, rate-response control parameters adapted for converting an activity sensor signal to a rate-responsive pacing parameter.

13. The pacemaker according to claim 1 further comprising:

a receiving amplifier/filter adapted for multiple controllable gain settings; and

the processor configured to control gain setting for the receiving amplifier/filter, invoking a low-gain setting for normal operation and detecting presence of a cardiac pacing pulse, and invoking a high-gain setting for detecting and decoding information encoded in the detected cardiac pacing pulse.

14. The pacemaker according to claim 1 further comprising:

a tank capacitor coupled across a pair of the electrode plurality and adapted for charging and discharging wherein a pacing pulse is generated;

a charge pump circuit coupled to the tank capacitor and adapted for controlling charging of the tank capacitor; and

the processor configured to control recharging of the tank capacitor wherein recharging is discontinued when a battery terminal voltage falls below a predetermined value to ensure sufficient voltage for powering the leadless cardiac pacemaker.

15. A pacemaker comprising:

the pacemaker configured as a leadless cardiac pacemaker comprising;

a housing;

a plurality of electrodes coupled to the housing;

a pulse generator hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse generator configured for generating and delivering electrical pulses to the electrode plurality;

at least one amplifier hermetically contained within the housing and electrically coupled to the electrode plurality, the at least one amplifier configured to amplify signals received from the electrode plurality and amplify signals for cardiac sensing;

a power supply hermetically contained within the housing and coupled to the pulse generator, the power supply configured to source energy for the electrical pulses from internal to the housing;

an activity sensor hermetically contained within the housing and adapted to sense activity; and

a processor hermetically contained within the housing and communicatively coupled to the pulse generator, the amplifier, the activity sensor, and the electrode plurality, the processor configured to receive amplifier output signals from the amplifier and control electrical pulse delivery at least partly based on the sensed activity.

16. The pacemaker according to claim 15 further comprising:

the plurality of electrodes coupled on, within, or within two centimeters of the housing.

17. The pacemaker according to claim 15 further comprising:

the processor that controls electrical pulse delivery and application of the activity sensor according to at least one programmable parameter, the processor being programmable by communication signals transmitted via the electrode plurality.

18. The pacemaker according to claim 15 further comprising:

the activity sensor adapted for controlling rate-responsive pacing and selected from a group consisting of an accelerometer, a temperature sensor, and a pressure sensor.

19. The pacemaker according to claim 15 further comprising:

the activity sensor comprising an accelerometer and accelerometer amplifier configured to detect patient activity for rate-responsive pacing.

20. The pacemaker according to claim 19 further comprising:

the processor configured to sample signals from the accelerometer synchronously with a cardiac cycle determined by the pulse delivery system, compare acceleration signals acquired at relative times in multiple cardiac cycles, and distinguishes acceleration signals resulting from activity from signals resulting from cardiac wall motion.

21. The pacemaker according to claim 15 further comprising:

the activity sensor comprising a temperature transducer, the temperature transducer comprising a thermistor and a signal conditioning amplifier connected to the processor.

22. The pacemaker according to claim 15 further comprising:

the activity sensor comprising a pressure transducer and a signal conditioning amplifier connected to the processor.

23. The pacemaker according to claim 15 further comprising:

the activity sensor that operates with a power requirement of no more than approximately 10 microwatts.

24. A pacemaker comprising:

the pacemaker configured as a leadless cardiac pacemaker comprising;

a housing;

a plurality of electrodes coupled to the housing;

a pulse generator hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse generator configured for generating and delivering electrical pulses to the electrode plurality and causing cardiac contractions, the pulse generator further configured for conveying information to at least one device external to the pacemaker;

at least one amplifier hermetically contained within the housing and electrically coupled to the electrode plurality, the at least one amplifier configured to amplify signals received from the electrode plurality and to detect cardiac contractions, the at least one amplifier further configured to receive information from the at least one external device;

a power supply hermetically contained within the housing and coupled to the pulse generator, the power supply configured to source energy for the electrical pulses from internal to the housing;

an activity sensor hermetically contained within the housing and adapted to sense activity; and

a processor hermetically contained within the housing and communicatively coupled to the pulse generator, the at least one amplifier, the activity sensor, and the electrode plurality, the processor configured to receive amplifier output signals from the amplifier and control electrical pulse delivery at least partly based on the sensed activity.

25. The pacemaker according to claim 24 further comprising:

the plurality of electrodes coupled on, within, or within two centimeters of the housing.

26. The pacemaker according to claim 24 further comprising:

the activity sensor adapted for controlling rate-responsive pacing and selected from a group consisting of an accelerometer, a temperature sensor, and a pressure sensor.

27. The pacemaker according to claim 24 further comprising:

the at least one amplifier comprising a cardiac sensing amplifier that consumes no more than 5 microwatts, a communications amplifier that consumes no more than 25 microwatts, and a rate-response sensor amplifier that consumes no more than 10 microwatts.

28. The pacemaker according to claim 24 further comprising:

the power supply configured to consume electrical power of no more than 2 microwatts and configured to supply electrical power of no more than 74 microwatts.

29. The pacemaker according to claim 24 further comprising:

the processor configured to consume electrical power of no more than 5 microwatts averaged over one cardiac cycle.

30. A pacemaker comprising:

the pacemaker configured as a leadless cardiac pacemaker comprising;

a housing;

a plurality of electrodes coupled to the housing;

a pulse generator hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse generator configured to generate and deliver electrical pulses to the electrode plurality powered from a source contained entirely within the housing;

an activity sensor hermetically contained within the housing and adapted to sense activity; and

a logic hermetically contained within the housing and communicatively coupled to the pulse generator, the activity sensor, and the electrode plurality, the logic configured to control electrical pulse delivery at least partly based on the sensed activity.

31. The pacemaker according to claim 30 further comprising:

the plurality of electrodes coupled on, within, or within two centimeters of the housing.

32. A pacemaker comprising:

the pacemaker configured as a leadless cardiac pacemaker comprising;

a housing;

a plurality of electrodes coupled to the housing;

a pulse generator hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse generator configured for generating and delivering electrical pulses to the electrode plurality;

an activity sensor hermetically contained within the housing and adapted to sense activity; and

a processor hermetically contained within the housing and communicatively coupled to the pulse generator, the activity sensor, and the electrode plurality, the processor configured to control electrical pulse delivery at least partly based on the sensed activity and configured to communicate with at least one device external to the pacemaker via the electrode plurality.

33. The pacemaker according to claim 32 further comprising:

the plurality of electrodes coupled on, within, or within two centimeters of the housing.

34. The pacemaker according to claim 32 further comprising:

the processor that controls electrical pulse delivery and application of the activity sensor according to at least one programmable parameter, the processor being programmable by communication signals transmitted via the electrode plurality.

35. The pacemaker according to claim 32 further comprising:

the processor that communicates to the at least one device external to the pacemaker by communication signals transmitted via the electrode plurality.

36. A method for operating a pacemaker comprising:

sensing electrical signals conducted through a body;

decoding and storing information encoded in the electrical signals;

sensing an activity sensor signal within the pacemaker;

converting the activity sensor signal to a rate-responsive pacing parameter as a function of the stored information; and

controlling pacing pulse delivery as a function of the rate-responsive pacing parameter.

37. The method according to claim 36 further comprising:

encoding information in the electrical signals comprising;

generating and delivering electrical energy with a stimulation pulse interrupted by at least one notch that conveys information.

38. The method according to claim 36 further comprising:

encoding information in the electrical signals comprising;

generating and delivering electrical energy with a stimulation pulse that conveys information in designated codes encoding the information in pacing pulse width.

39. The method according to claim 36 further comprising:

encoding information in the electrical signals comprising;

generating and delivering electrical energy with a stimulation pulse that conveys information in designated codes encoding the information in modulation of off-time between pacing pulses.

40. A method for operating a pacemaker comprising:

implanting a leadless cardiac pacemaker to cardiac muscle, the leadless cardiac pacemaker further comprising a rate-response sensor;

measuring an activity signal using the rate-response sensor, the activity signal including an artifact signal resulting from cardiac muscle motion;

sampling the activity signal synchronously with a cardiac cycle;

monitoring the activity signal at identified points in the cardiac cycle; and

removing the artifact signal from the activity signal based on the monitoring.

41. The method according to claim 40 further comprising:

measuring the activity signal using an accelerator.

42. The method according to claim 40 further comprising:

measuring the activity signal using a thermistor or pressure sensor.