System and method for walking an implantable medical device from a sleep state

• US 7,650,185 B2
• Filed: 04/25/2006
• Issued: 01/19/2010
• Est. Priority Date: 04/25/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Jeffrey, Von Arx A., Zhang, Cheng, Chavan, Abhijeet V., Maile, Keith R.
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Gedeon; Brian T
• Application Number:
  US11/380,112
• Publication Number:
  US 20070250126A1
• Time in Patent Office: 1,365 Days
• Field of Search: 607/16
• US Class Current: 607/16
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371
• 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 1/37264 Changing the program; Upgrading firmware
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient

Abstract

A system and method for waking up an implantable medical device (“IMD”) from a sleep state in which power consumption by the IMD is essentially zero. The IMD may be adapted to perform one or more designated measurement and/or therapeutic functions. In one embodiment, the IMD includes a wake-up sensor that is adapted to sense the presence or absence of a wake-up field generated by another IMD or an external device. The wake-up field may, in some embodiments, be an electromagnetic field, a magnetic field, or a physiologically sub-threshold excitation current (i.e., E-field). Upon sensing by the wake-up sensor of the wake-up field, other components of the IMD, which may include a controller, a sensing and/or therapy module, and/or a communications module, are awakened to perform one or more designated functions.

Claims

1. A method carried out by a satellite implantable medical device for being awakened from a sleep state by a primary implantable medical device, the satellite implantable medical device including a wake-up sensor, a control module, a physiologic sensor, a power supply, and a communication module , the method comprising:

waiting in a sleep state, wherein only sensing circuitry of the wake-up sensor is energized and powered on for detecting and processing an output voltage from the wake-up sensor;

detecting, by the wake-up sensor, the presence of an electromagnetic wake-up field generated by the primary implantable medical device;

responsive to detecting the presence of the electromagnetic wake-up field, prompting power control circuitry coupled to the power supply to supply electrical power to the control module and the communication module, causing the control module and communication module to change from the sleep state to an active state; and

wherein, in the active state, the control module causes the physiologic sensor to activate and sense at least one physiologic parameter, and the communication module to wirelessly transmit the at least one sensed physiologic parameter to the primary implantable medical device.

2. The method of claim 1 wherein the communication module is adapted for acoustic communication, and further wherein the physiologic sensor includes a pressure sensor adapted to measure pressure within a blood vessel, and wherein the at least one physiologic parameter is a pulmonary arterial blood pressure.

3. The method of claim 1 further comprising:

inductively coupling a first inductive coil of the primary implantable medical device to a second inductive coil of the satellite implantable medical device; and

passing an alternating current through the first inductive coil to generate an electromagnetic field,

wherein the detecting step comprises detecting the electromagnetic field by the second inductive coil and generating an output voltage across the second inductive coil.

4. A method of waking an implantable medical device from a low-power state, the method comprising:

providing a first implanted medical device including a wake-up field generator and a first communication module, the wake-up field generator adapted to generate an electromagnetic wake-up field;

providing a second implanted medical device including a battery, a wake-up sensor operable to detect the electromagnetic wake-up field, a physiologic sensor, a control module, and a second communication module configured to acoustically communicate with the first implanted medical device, wherein the second implanted medical device is initially in a low-power state in which only sensing circuitry of the wake-up sensor is energized and powered on for detecting and processing an output voltage from the wake-up sensor;

detecting, by the wake-up sensor, the presence of the electromagnetic wake-up field generated by the first implanted medical device;

responsive to detecting the presence of the electromagnetic wake-up field, prompting power control circuitry coupled to the battery to supply electrical power to the control module and the communication module, causing the control module and the communication module to change from the low-power state to an active state; and

wherein, in the active state, the control module causes the physiologic sensor to activate and sense at least one physiologic parameter, and the second communication module to acoustically transmit the at least one sensed physiologic parameter to the first implanted medical device.

5. The method of claim 4 wherein the physiologic sensor includes a pressure sensor, and wherein the at least one physiologic parameter is a pulmonary arterial blood pressure.

6. The method of claim 4 further comprising:

inductively coupling a first inductive coil of the first implanted medical device to a second inductive coil of the second implanted device; and

passing an alternating current through the first inductive coil to generate an electromagnetic field,

wherein the detecting step comprises detecting the electromagnetic field by the second inductive coil and generating an output voltage across the second inductive coil.

7. A system for waking up an implantable medical device from a sleep state, the system comprising:

a primary implantable device including a wake-up field generator operable to generate an electromagnetic wake-up field, and a first communication module; and

a satellite implantable device including;

a control module;

a pressure sensor adapted to sense blood pressure within a body lumen;

a second communication module configured to acoustically communicate with the first communication module, wherein the control module and the second communication module are adapted to change between a sleep state and an active state in response to the electromagnetic wake-up field; and

means for detecting the electromagnetic wake-up field.

8. The system of claim 7 wherein the wake-up field generator includes a first inductive coil, and wherein the means for detecting the wake-up field include a second inductive coil inductively coupled to the first inductive coil.

9. The system of claim 7 wherein the satellite implantable device further comprises timer circuitry operable to cause, at a first predetermined time interval, the means for detecting the wake-up field adapted to change from a sleep state to an active state in which the means for detecting the wake-up field are operable to detect the wake-up field.

10. The system of claim 9 wherein the timer circuitry is further adapted to cause the means for detecting the wake-up field to return to the sleep state upon passage of second predetermined time interval.

11. The system of claim 10 wherein the wake-up field generator includes a magnetic field generator, and wherein the means for detecting the wake-up field include a magnetic field sensor.

12. The system of claim 10 wherein the wake-up field generator is adapted to generate a physiologically sub-threshold electrical excitation current, and wherein the means for detecting the wake-up field include an electric field sensor adapted to detect the excitation current.