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Publication numberUS20070055324 A1
Publication typeApplication
Application numberUS 11/554,212
Publication date8 Mar 2007
Filing date30 Oct 2006
Priority date26 Nov 2003
Also published asUS7209790, US20040167587, WO2005053786A2, WO2005053786A3
Publication number11554212, 554212, US 2007/0055324 A1, US 2007/055324 A1, US 20070055324 A1, US 20070055324A1, US 2007055324 A1, US 2007055324A1, US-A1-20070055324, US-A1-2007055324, US2007/0055324A1, US2007/055324A1, US20070055324 A1, US20070055324A1, US2007055324 A1, US2007055324A1
InventorsDavid Thompson, Koen Weijand, Daniel Greeninger
Original AssigneeThompson David L, Weijand Koen J, Greeninger Daniel R
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Multi-mode coordinator for medical device function
US 20070055324 A1
Abstract
The invention is directed to an externally applied coordinator for communication and/or control of 2 or more implantable medical devices that may utilize different telemetry communication techniques. The coordinator receives telemetry signals from 2 or more implantable medical devices and provides functional direction to each of the devices to provide coordinated therapy and/or diagnostic function. The coordinator automatically configures itself for communication with a given medical device based either on the telemetry signal it receives or programmed by the physician. Specifically the coordinator is implemented as a software based, power efficient receiver/transmitter based upon an inexpensive, simple motor-controller DSP.
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Claims(28)
1. A system comprising:
a first implanted medial device;
a second implanted medial device; and
a coordinator that receives data via a first communication signal from the first medial device, produces a function command, generates a second communication signal and sends the function command via the second communication signal to the second medical device.
2. The first implantable medical device of claim 1 selected from the group consisting of a pacemaker, a defibrillator, a cardioverter/defibrillator, a drug pump, a neuro stimulator, an ILR and a remote sensor.
3. The second implantable medical device of claim 1 selected from the group consisting of a pacemaker, a defibrillator, a cardioverter/defibrillator, a drug pump, a neuro stimulator, an ILR and a remote sensor.
4. The function command of claim 1 coordinates therapy between the first and second implantable medical devices.
5. The therapy of claim 4 selected from the group consisting of pacing, cardioversion/defibrillation, neuro stimulation and drug delivery.
6. The function command of claim 1 coordinating sensing and monitoring between the first and second implantable medical devices.
7. The function command of claim 1 providing pain suppression to the patient from a first implantable medical device prior to or during therapy from the second implantable medical device.
8. The function command of claim 1 providing reduced defibrillation or pacing threshold of the patient from a first implantable medical device prior to or during therapy from the second implantable medical device.
9. The function command of claim 1 providing remote sensor data from the first implantable medical device to the second medical device.
10. The function command of claim 1 providing device protection to the first implantable medical device during therapy delivery from the second implantable medical device.
11. The remote sensor data of claim 9 selected from the group consisting of acceleration, pressure, O2sat, pH, flow, dP/dt, acoustic (sound), Doppler ultrasound, impedance plethsymmography and piezo-electric.
12. The coordinator of claim 1 mounted externally to the patient.
13. The coordinator of claim 12 selected from the group consisting of a wrist watch, a belt, a necklace, a piece of jewelry, an adhesive patch, a pager, a key fob, an identification card, a laptop computer, an interrogator and a hand-held computer.
14. The first and second communication signals from the coordinator of claim 1 consisting of a trancutaneous telemetry transmission.
15. The first and second communication signals of claim 14 selected from the group consisting of RF, electromagnetic, ionic and acoustic.
16. The coordinator of claim 1 communicating between 2 IMDs selected from the group consisting of a pacemaker and ICD, a pacemaker and drug pump, an ICD and drug pump, a pacemaker and neuro stimulator, an ILR and pacemaker, an ILR and ICD, an ILR and neuro stimulator, an ILR and drug pump and an ICD and neuro stimulator.
17. The neuro stimulator of claim 16 providing therapy to the patient's vagus nerve or brain.
18. The pacing therapy of claim 5 selected from the group consisting of ATP pacing, overdrive pacing and bradycardia pacing.
19. The reduced ICD pain delivery of claim 7 selected from the group consisting of a neuro stimulator and drug pump.
20. The reduced defibrillation shock threshold of claim 8 reduced by therapy delivered from an IMD selected from the group consisting of a neuro stimulator, a drug pump and a pacemaker.
21. The coordinated sensing of physiologic data of claim 6 selected from the group consisting of cardiac signals, respiration signals and EEG signals.
22. The neuro stimulator or drug pump of claim 5 providing therapy for a disease selected from the group consisting of Parkinson's and epilepsy.
23. The communication system of claim 1 with telemetry setup selected from the group consisting of automatic setup, physician programmed and implant detect and automatic setup.
24. The coordinator of claim 1 including a digital signal processor (DSP) circuit comprising:
means for receiving a data signal from a first IMD;
means for generating a control command; and
means for modulating a second signal with said function command and transmitting said second signal to a second IMD.
25. The coordinator of claim 24 further comprising:
an antenna system;
a receiver in operable communications with the antenna for receiving and amplifying of said data signal; and
a transmitter for transmitting a function command to said one of IMDs.
26. The coordinator of claim 24 further comprising:
a patient activated push button for providing manual input by the patient selected from the group consisting of arrhythmia onset, the feeling of light-headedness, the beginning of a meal, chest pains, to manually activate diagnostic data recording and initiate therapy delivery.
27. The monitoring therapy of claim 6 selected from the group consisting of EEG, cardiac, obstructive sleep apnea (OSA), central apnea and neurogenic pulmonary edema.
28. A method of coordinating the function of 2 IMDs implanted in a patient, comprising:
receiving a communication signal from a first IMD;
decoding the data from said communication signal;
utilizing said decoded data to generate a function command for said second IMD;
modulating a second communication signal with said data;
transmitting said second communication signal to said second IMD;
receiving said second communication signal by said second IMD; and
causing the second IMD to operate in a specific function/method.
Description
    RELATED APPLICATIONS
  • [0001]
    This application is a continuation in part of Ser. No. 10/722,891, filed Nov. 26, 2003.
  • FIELD OF THE INVENTION
  • [0002]
    The invention relates to implantable medical devices, particularly, medical devices equipped to communicate via transmitting and receiving transcutaneously transmitted telemetry signals. More particularly, the invention relates to a device and method for the coordination of function between 2 or more implantable medical devices with or without similar telemetry systems. In particular, the inventive device is constructed in a temporary tape-on form from an energy efficient, inexpensive, and simple motor controller DSP.
  • BACKGROUND OF THE INVENTION
  • [0003]
    Today, as the population ages, implantable medical devices (IMDs) are in use for various cardiac, pulmonary and neurological diseases. In fact, many elderly patients often have multiple disease states that may be helped by several different IMDs. Additionally, several neuro-cardiology diseases have several simultaneous physiologic manifestations. For example, epilepsy may often have concomitant cardiac and/or pulmonary anomalies and Parkinson's Disease patients also often have cardiac arrhythmia manifestations. Often epilepsy or Parkinson's patients that have been newly diagnosed or have transient periods when their current medicants are no longer effective and must be changed/modified (i.e., drug type, dosage levels, timing, etc.), have transient episodes of cardiac or pulmonary anomalies that may last a few days, a few weeks to several months in length.
  • [0004]
    Additionally, often when an IMD is required for implantation, another device may already be implanted in the patient (i.e., a neuro stimulator may now be required for recently diagnosed epilepsy and a pacemaker or ICD may already be present for cardiac anomalies such as bradycardia or tachyarrhythmia). With IMDs generally having a longevity of 5-8 years minimum, and many lasting 15 years, it would be cost effective for a physician to make use of the remaining life of the previously implanted device and, in doing so, may improve the effectiveness of the therapy delivered to the patient, reduce the pain/discomfort of therapy delivered and/or improve diagnostics of the new device implanted. The 2 IMD devices would have to have their operation and function synchronized and coordinated to provide these benefits.
  • [0005]
    One issue with the integration of 2 or more IMDs in a patient is the additional “overhead” of software required for system function, integration of function, intra-device communication, new algorithms for therapies or diagnostics and the like. Most IMDs have little free RAM or downloadable code space left in the device after implant to be able to function as the system integrator/coordinator.
  • [0006]
    Another issue with the synchronization of operation of 2 IMDs is that the telemetry method, modulation and/or coding format may be different between, and complicating the communication between, the 2 devices. Additionally, as above, neither of the 2 IMDs would unlikely be able to provide the code space and circuit capability to allow the modulation, demodulation, coding and decoding of telemetry formats to allow this intra-device communication.
  • [0007]
    In this context, telemetry generally refers to communication of data, instructions, and the like between a medical device and a medical device programmer operated by a physician. For example, a programmer may use telemetry to program a medical device to deliver a particular therapy to a patient. In addition, the programmer may use telemetry to interrogate the medical device. In particular, the programmer may obtain diagnostic data, event marker data, activity data and other data collected or identified by the medical device. The data may be used to program the medical device for delivery of new or modified therapies. In this manner, telemetry between a medical device and a programmer can be used to improve or enhance medical device therapy.
  • [0008]
    Telemetry typically involves wireless data transfer between a medical device and the programmer using radio frequency (RF) signals, infrared (IR) frequency signals, or other electromagnetic signals. Any of a variety of modulation techniques may be used to modulate data on a respective electromagnetic carrier wave. Alternatively, telemetry may be performed using wired connections, sound waves, or even the patient's flesh as the transmission medium. A number of different telemetry systems and techniques have been developed to facilitate the transfer of data between a medical device and the associated programmer.
  • [0009]
    Many IMDs support telemetry. Examples of telemetry-capable IMDs include implantable cardiac pacemakers, implantable defibrillators, implantable pacemaker/cardioverter/defibrillators (ICDs), implantable muscular stimulation devices, implantable brain stimulators, other implantable organ stimulation devices, implantable drug delivery devices, implantable cardiac monitors or loop recorders (ILRs), and the like. Telemetry, however, is not limited to communication with IMDs. For example, telemetry may allow an IMD to communicate with non-implanted medical devices in substantially the same way as it is used with programmers. Examples include patient-carried monitors, patient activators, remote monitoring systems and the like.
  • [0010]
    The evolution and advancement of IMD telemetry has yielded a number of advances in the art including, for example, improved communication integrity, improved data transmission rates, improved communication security, and the like. Moreover, as new therapeutic techniques are developed, telemetry allows the new techniques to be programmed into older medical devices, including devices previously implanted in a patient. Unfortunately, the evolution of telemetry has also resulted in proliferation of a wide variety of different systems and communication techniques that generally require a unique programmer for communication with each type of device. Consequently, different types of medical devices, medical devices manufactured by different companies, or even similar medical devices manufactured by the same company, often employ different telemetry techniques. Accordingly, a wide variety of different programmers are needed to communicate with different medical devices in accordance with the different telemetry techniques employed by the medical devices.
  • [0011]
    A proposed solution to the large and diverse number of programmers required in a hospital and/or follow-up clinic environment to program, interrogate or follow patients with IMDs is a “universal programmer” as proposed, for example, by P Stirbys in “A Challenge: Development of a Universal Programmer”, PACE, Vol 16, April 1993, pg 693-4 and by R Fortney, et al. in “Activation Times for “Emergency Backup” Programs”, PACE, Vol 19, April 1996, pg 465-71. As pointed out in these articles, the difficulty of implementing multiple up/down link formats in a single programmer is formidable.
  • [0012]
    Prior art programmers have included optimized and customized bandpass filters and demodulators for demodulating and detecting the telemetered data signal from an IMD from a particular manufacturer. It would be prohibitively expensive, large and complex to incorporate the required amplification, filtering and demodulation of all manufacturers' IMDs in a single programmer.
  • [0013]
    Additionally, the integration of the circuitry and firmware/software into IMDs to allow intra-device communication and system integration/control would be unduly complex, bulky, power hungry and very difficult from a mechanical packaging perspective. There is a need for an energy efficient system integrator and coordinator apparatus that is configurable to receive and demodulate data telemetered from a variety of implantable devices and communicate to another IMD providing integrated/coordinated diagnostic function and/or therapy deliverable to a patient. The present invention fulfills this need.
  • SUMMARY OF THE INVENTION
  • [0014]
    In general, the invention is directed to a system coordinator for 2 or more IMDs and the communication between those medical devices that may utilize different telemetry communication techniques. The system coordinator receives telemetry signals from a given medical device, and selects an appropriate communication mode, which can be pre-programmed into the coordinator as one of a plurality of possible communication modes. For example, upon receiving a telemetry signal from the medial device, the coordinator may identify a signature associated with the received telemetry signal. The coordinator can then select the appropriate communication mode, such as by accessing a lookup table that associates signatures with communication modes. Accordingly, the coordinator can selectively configure itself for communication with a given medical device based on the telemetry signal it receives from that medical device.
  • [0015]
    In one embodiment, the invention provides a method comprising receiving a first signal from a medical device, and selecting a communication mode from a plurality of possible communication modes based on the first signal. For example, selecting the communication mode based on the first signal may include identifying a signature that substantially correlates to the first signal, and selecting a communication mode associated with the signature.
  • [0016]
    In another embodiment, the invention provides a system comprising a first medial device, a second medial device, and a system coordinator. For example, the coordinator receives a first signal from the first medial device, selects a first communication mode from a plurality of possible communication modes based on the first signal, generates a second signal that complies with the first communication mode, sends the second signal to the first medical device, receives a third signal from the second medial device, selects a second communication mode from the plurality of possible communication modes based on the third signal, generates a fourth signal that complies with the second communication mode, and sends the fourth signal to the second medical device.
  • [0017]
    In yet another embodiment, the communication modes may be simply programmed by the patient's physician based on the model numbers of the IMDs present.
  • [0018]
    The present invention provides various advances in the art. In particular, the invention can allow the extension of the useful lifetime of an IMD and/or provide improved function, including diagnostics and therapy, by allowing intra-device communication and system coordination between 2 or more IMDs. A multi-mode system coordinator can be used to communicate and provide system integration and coordination on a selective basis between a plurality of different medical devices with, or without, differing telemetry communication modes.
  • [0019]
    The invention may also provide distinct advances in the art in terms of the size (form factor) and mechanical configuration of a coordinator, useful for improved patient therapy and/or diagnostics. For example, a number of mechanical configurations are envisioned, including wearable configurations such as configurations similar to jewelry, a wristwatch or a belt buckle to be worn by the patient or medical personnel. In addition, a coordinator in the form of an ID card or adhesive patch with a removable memory card are envisioned for use by a patient so that diagnostic information can be collected on the removable memory card when the patch is adhered to the patients skin. In that case, the memory card may be removed from the coordinator and sent it to a physician for analysis without the need to send the entire coordinator to the physician. Accordingly, the coordinator can be reused with another memory card. Of course, the coordinator itself could also be sent by the patient to the physician, in accordance with other embodiments. These and other unique wearable configurations can be realized in various embodiments of the invention, some of which may have dimensions less than approximately 60 millimeters by 90 millimeters by 15 millimeters, i.e., a form factor similar to that of a thick credit card.
  • [0020]
    The techniques described herein may be implemented in a system coordinator in hardware, software, firmware, or any combination thereof. If implemented in software, invention may be directed to a computer readable medium comprising program code, that when executed, performs one or more of the techniques described herein. Additional details of various embodiments are set forth in the accompanying drawings and the description below. Other features, objects and advances in the art will become apparent from the description and drawings, and from the claims.
  • BRIEF DESCRIPTION OF DRAWINGS
  • [0021]
    FIG. 1 is a conceptual diagram illustrating a multi-mode programmer communicating with an exemplary medical device implanted in a human body.
  • [0022]
    FIG. 2 is a block diagram illustrating telemetry between a multi-mode programmer and a set of different medical devices.
  • [0023]
    FIG. 3 is a block diagram of a multi-mode programmer that supports a plurality of communication modes for communicating with different medical devices via different telemetry techniques.
  • [0024]
    FIG. 4 is a more detailed block diagram of a multi-mode programmer.
  • [0025]
    FIGS. 5 and 6 are diagrams illustrating an embodiment of a multi-mode programmer taking the form of an adhesive patch.
  • [0026]
    FIGS. 7 and 8 are flow diagrams illustrating techniques in accordance with embodiments of the invention.
  • [0027]
    FIG. 9 is a diagram illustrating an alternative embodiment utilizing the multi-mode programmer of the invention.
  • [0028]
    FIG. 10 is a simplified schematic representation of the software based multi-mode programmer of the present invention.
  • [0029]
    FIG. 11 is a schematic diagram of the front-end receiver, transmitter coil interface and DSP portions of the multi-mode programmer according to an embodiment of the invention.
  • [0030]
    FIG. 12 is a diagram of the uplinked RF telemetry signal from an implanted medical device showing one embodiment of ping detection and demodulation.
  • [0031]
    FIG. 13 is a diagram of an uplinked RF signal showing a zero crossing extrapolation according to an embodiment of the invention.
  • [0032]
    FIG. 14 is a diagram of an uplinked RF signal showing a power reduction technique utilizing a window sampling method.
  • [0033]
    FIG. 15 is a conceptual diagram illustrating a multi-mode coordinator of the present invention communicating with 2 exemplary medical devices implanted in a human body.
  • [0034]
    FIG. 16 is a diagram of a method of implementing the implanting of a second IMD and initiating communication between the first and second IMDs.
  • DETAILED DESCRIPTION
  • [0035]
    FIG. 1 is a conceptual diagram illustrating a multi-mode programmer 5 communicating with an exemplary medical device 8 implanted in a human body 10. Medical device 8 represents one of a variety of medical devices that may communicate with programmer 5. Although illustrated as an implantable cardiac pacemaker, medical device 8 may take the form of a variety of other medical devices such as, for example, an implantable defibrillator, an implantable pacemaker/cardioverter/defibrillator, an implantable muscular stimulus device, an implantable brain stimulator, an implantable nerve stimulator, an implantable drug delivery device, implantable monitor, or the like. In addition, medial device 8, as described herein, is not necessarily limited to an implantable device. Also, in some cases, medical device 8 may correspond to a medical device used on non-human mammals or other animals. In short, the techniques described herein may be readily used with a wide variety of medical devices including implanted and non-implanted medical devices used to deliver therapy or perform diagnosis in humans, mammals, or other types of living beings.
  • [0036]
    In the example shown in FIG. 1, medical device 8 includes a hermetically sealed enclosure 14 that may include various elements, although the invention is not limited to hermetically sealed devices. By way of example, enclosure 14 may house an electrochemical cell, e.g., a lithium battery, circuitry that controls device operations and records sensed events, physiological activity and patient conditions, and a control unit coupled to an antenna to transmit and receive information via wireless telemetry signals 12.
  • [0037]
    Programmer 5 communicates with medical device 8 via telemetry signals 12. For example, programmer 5 may use telemetry signals 12 to program medical device 8 to deliver a particular therapy to human body 10, such as electrical stimulation, drug administration or the like. In addition, medical device 8 may use telemetry signals 12 to send information to programmer 5 such as diagnostic information, sensed conditions associated with the patient, information relating to therapy delivered to the patient, or any other information collected or identified by medical device 8. In this manner, telemetry allows communication between medical device 8 and programmer 5.
  • [0038]
    In accordance with the invention, programmer 5 supports communication via a number of different telemetry modes. Accordingly, programmer 5 is capable of receiving and interpreting telemetry signals sent by medical devices that use different types of telemetry. Moreover, programmer 5 can communicate to different medical devices using selected communication modes that correspond to the given medical device with which programmer 5 is currently communicating. The different telemetry modes of programmer 5 may cause programmer 5 to select different telemetry techniques. For example, programmer 5 may be equipped to detect characteristic features of signals sent to programmer 5 via different communication modes, such as unique carrier waveform shapes, amplitudes, frequency and/or timing of the modulated waveform, or the like. Based on the detected characteristics, programmer 5 selects one of the telemetry modes appropriate for communication with medical device 8.
  • [0039]
    Programmer 5 may be embodied in a wide variety of mechanical configurations. By way of example, programmer 5 may comprise a device worn on a patient's wrist, much like a wrist watch, and may even comprise a fully functional wrist watch that tells time, but also includes the programmer functionality described herein. Alternatively, programmer 5 may be worn around a patient's neck, like a necklace, or around a patient's waist, like a belt. In other configurations, programmer 5 may be embodied in an identification card, a pendent, a laptop computer, a handheld computer, a pager, or the like. In some cases, programmer 5 may comprise a programmed computer used by emergency medical personnel, e.g., in an ambulance, to communicate with a variety of possible medical devices that may be implanted within a given patient. In still other cases, programmer 5 may be embodied as an adhesive patch that is adhered to a patient's skin. These and other configurations of programmer 5 may be used in accordance with the invention.
  • [0040]
    In any case, programmer 5 receives telemetry signals 12 from a given medical device 8, and dynamically selects an appropriate communication mode, which can be pre-programmed into programmer 5 as one of a plurality of possible communication modes. For example, upon receiving a telemetry signal 12 from medical device 8, programmer 5 may identify a signature associated with the telemetry signal 12. Programmer 5 may then select the appropriate communication mode, such as by accessing a lookup table (LUT) that associates signatures with communication modes. Then, the programmer 5 can configure itself for communication with medical device 8 based on the telemetry signal 12 received from medical device 8.
  • [0041]
    FIG. 2 is a block diagram illustrating telemetry between programmer 5 and a set of different medical devices 8A-8D. Again, the different medical devices 8A-8D may comprise any of a wide variety of medical devices, including implanted and non-implanted medical devices, used to deliver therapy to humans, mammals, or even other types of living beings. In accordance with the invention, the different devices 8A-8D communicate using different telemetry techniques. In other words, the format of telemetry signal 12A is different from that of 12B, 12C and 12D. For example, different telemetry signals 12 may have distinct carrier waveforms defined by amplitude and frequency. Also, different telemetry signals 12 may be modulated differently, e.g., using amplitude modulation (AM), frequency modulation (FM), pulse width modulation (PWM), pulse code modulation (PCM), pulse position modulation (PPM), or the like. Also, different coding schemes may be associated with different signals 12, such as phase-shift keying (PSK), orthogonal coding, frame based coding, or the like. Programmer 5 may identify these unique characteristics of the raw signal without performing a demodulation in order to identify the communication mode. An appropriate demodulator can then be selected, as well as appropriate signal transmission techniques and components.
  • [0042]
    Programmer 5 supports communication with the different devices 8A-8D by supporting communication via each of the different telemetry communication modes associated with signals 12A-12D. In particular, programmer 5 selectively switches communication modes to match the communication mode of medical device 8, and thereby permit programming, interrogation or both. Programmer 5 may be configured to receive signals in a frequency band known to correlate to all of telemetry signals 12, or may periodically tune to different frequency bands to tune for reception of different telemetry signals 12 over time.
  • [0043]
    The different medical devices 8A-8D may correspond to different types of devices, i.e., devices that deliver different types of therapy. Alternatively medical devices 8A-8D may comprise similar devices manufactured by different companies, which use different telemetry techniques. In addition, medical devices 8A-8D may correspond to similar devices manufactured by the same company, but which use different telemetry techniques.
  • [0044]
    In most cases, medical devices 8A-8D correspond to different devices implanted or used on different patients. In some cases, however, medical devices 8A-8D may correspond to different devices implanted or used in one particular patient. In other words, a patient may have more than one medical device 8 implanted within his or her body. In that case, programmer 5 may support communication with all of the different devices implanted and used within the same patient. In any case, the need for distinct programmers for each device can be eliminated in favor of a single multi-mode programmer 5 that supports a plurality of communication modes.
  • [0045]
    FIG. 3 is an exemplary block diagram of a programmer 5 that supports a plurality of communication modes for communicating to different medical devices via different telemetry techniques. Programmer 5 is configured to dynamically select different communication modes according to the communication modes presented from medical devices 8. As illustrated, programmer 5 may include an antenna 32, a control unit 34, a memory 36, and a power supply 38.
  • [0046]
    Antenna 32 may send and receive different electromagnetic telemetry signals 12, such as radio frequency signals, as directed by control unit 34. The invention, however, is not limited for use with electromagnetic telemetry signals, but may also used with other telemetry signals, including sound waves. In addition, in some embodiments, programmer 5 may use the patient's flesh as a transmission line for communication of electromagnetic signals between medical devices and programmer 5.
  • [0047]
    In any case, programmer 5 supports communication according to a plurality of telemetry modes. In operation, control unit 34 of programmer 5 receives telemetry signals via antenna 32. Antenna 32 may be tuned to a large frequency band that covers any possible telemetry signal that may be received from a device supported by programmer 5, or may be periodically tuned by control unit 34 to individual frequencies that correspond to specific telemetry signals that are supported. In any case, once a signal is received, control unit 34 conditions received signals so that signatures associated with the received signals can be identified. For example, control unit 34 may perform amplification or attenuation on received signals, and may also implement a phase locked loop to properly synchronize the phase of a received signal with the signatures to which the received signal is being compared.
  • [0048]
    The signatures may correspond to templates of expected waveforms that correspond to possible telemetry signals that could be received. The signatures may include distinctive waveform characteristics indicative of the respective telemetry signal, such as a particular frequency, amplitude, shape, modulation characteristic, or the like. Memory 36 stores the signatures for every telemetry technique that is supported by programmer 5. Accordingly, control unit 34 compares received signals with stored signatures by accessing memory 36. Then, after identifying an acceptable match between a stored signature and a received telemetry signal, e.g., 12A, programmer 5 is able to identify the telemetry technique associated with the medical device that sent signal 12A. In other words, the received signals can be compared to signatures, and the signatures can be mapped to communication modes.
  • [0049]
    Memory 36 may also store configuration parameters associated with different communication modes for control unit 34. In addition, memory 36 may include a lookup table (LUT) that maps signatures to communication modes, i.e., by mapping a number associated with a signature to a number associated with an associated communication mode. Thus, upon identifying a signature associated with a received telemetry signal 12A, control unit can access the LUT in memory 36 to select the proper communication mode. Then, control unit 34 can be configured according to the selected communication mode to output telemetry signals that the medical device associated with the received telemetry signal 12A can understand. In addition, control unit 34 can configure itself so that signals sent from the respective device can be properly demodulated and interpreted. In short, the different communication modes supported by programmer 5 can be programmed into memory 36, and then applied on a selective basis based on received telemetry signals 12.
  • [0050]
    FIG. 4 is a more detailed exemplary block diagram of programmer 5. As illustrated, programmer 5 includes a power supply 38, such as a battery, that powers control unit 34 and memory 36. Antenna 32 is coupled to control unit 34 to facilitate the reception and transmission of wireless electromagnetic telemetry signals. The invention, however, is not necessarily limited for use with wireless signals or electromagnetic signals. Again, similar principles can be applied in a programmer that can be wired to one or more medical devices, or a programmer that uses the patient's flesh or sound waves as the transmission medium for telemetric communication.
  • [0051]
    Control unit 34 may include a programmable digital signal processor (DSP) 42 coupled to a crystal oscillator (not shown). Examples of suitable DSPs include the TI-TMS320C2000 family of DSPs; such as the model number TI-TMS320LC2406 DSP, commercially available from Texas Instruments Incorporated of Dallas Tex., USA. By way of example, the oscillator may comprise a 5 MHz crystal, although other oscillators could be used. The TI-TMS320LC2406 DSP is a 16-bit fixed point DSP originally designed for motor control applications. The TI-TMS320LC2406 DSP includes internal flash memory and a 10-bit analog to digital converter (ADC). Other DSPs and programmable microprocessors, however, could alternatively be used.
  • [0052]
    Memory 36 may comprise a removable memory card that couples to DSP 42 via a memory connector, although non-removable memory could also be used. Removable memory cards can provide an added benefit in that the card can be removed from programmer 5 and sent to a physician for analysis. For example, after programmer 5 telemetrically communicates with a given medical device 8, data from that medical device may be stored in memory 36. The data stored in memory 36 may be data selected by programmer 5. In some cases, the data stored in memory 36 may be overflow data from an internal memory associated with medical device 8, allowing programmer 5 to provide more continuous and more prolonged patient monitoring capabilities. If memory 36 comprises a removable card, the card may be removed from programmer 5 and sent to a physician, and a new card may be inserted in its place. In this manner, data from a medical device 8 can be easily provided to a physician, e.g., to facilitate early diagnosis of problems.
  • [0053]
    Moreover, the use of memory cards can avoid the need to send the whole programmer 5 to the physician. In addition, a more continuous and larger sample of data from the medial device may be captured by sequentially inserting a number of memory cards into programmer 5 over a period of time in which information is being sent from the respective medical device. As one example, memory 36 may comprise a 64 or 256 Megabyte multimedia memory module commercially available by SanDisk of Sunnyvale, Calif., USA. Other removable or non-removable memory, however, may also be used.
  • [0054]
    Another advances in the art of removable memory cards and a DSP relates to updating the function of the programmer 5. For example, in order to update programmer 5 to support new or different forms of telemetric communication, a different memory card, storing software to support the new or different telemetry may be provided. In other words, a DSP configuration with removable memory provides advances in the art in terms of scalability of programmer 5. If new or different telemetry is developed, software can be likewise devolved and provided to programmer via a new removable memory card. Accordingly, in that case, the need to develop a different programmer may be avoided. Instead, new algorithms can be provided to programmer 5 via a new memory card that stores new instructions that can be executed by the DSP.
  • [0055]
    Antenna 32 may comprise any of a wide variety of antenna configurations. In one particular example, antenna 32 may comprise a substantially flat, co-planer dual opposing coil antenna. For example, two opposing coils may be formed on a common substrate to provide two signal inputs to control unit 34. The input of two or more signals to control unit 34 may simplify signal processing within control unit 34, such as by simplifying filtering. In addition, an antenna scheme utilizing multiple concentric and co-planar antenna coils on a substrate may also reduce the form factor of programmer 5, which can facilitate wearable embodiments. The use of concentric and co-planar antenna coils may also improve the reception of telemetry signals in a noisy environment.
  • [0056]
    Power supply 38 may comprise any of a wide variety of batteries or other power sources. For example, power supply 38 may comprise a rechargeable or non-rechargeable battery, such as a polymer or foil battery, a lithium ion batter, a nickel cadmium battery, or the like. The battery may have a voltage range of approximately 4.2 to 3.0 volts throughout its useful service life and a capacity of 1.5 Ah, although the invention is not limited in that respect.
  • [0057]
    In addition to DSP 42, control unit 34 of programmer 5 may include a receiver module 46 and a transmitter module 48. Receiver module 46 and transmitter module 48 may be integrated or may comprise separate circuits. The composition of receiver module 46 and transmitter module 48 may depend on the particular DSP 42 used in control unit 34 as well as the particular communication modes supported by programmer 5.
  • [0058]
    In general, receiver module 46 conditions a received telemetry signal for analysis by DSP 42. Receiver module 46 may include an analog-to-digital converter (ADC), although some DSPs, such as the TI-TMS320LC2406 mentioned above, include an ADC as part of the DSP. Receiver module 46 may also include one or more amplifiers, a variable gain amplifier (VGA), one or more filters, automatic gain control (AGC), if needed, and a phase-locked loop for synchronizing a received signal so that an in-phase sample can be identified. These and/or other components of receiver module 46 condition a received telemetry signal as required by DSP 42 so that signal analysis can be performed. In some cases, DSP 42 may configure both itself and receiver module 46 for reception of a given telemetry signal that is expected, such as by selectively switching on a subset of the bandpass filters in DSP 42 and controlling the gain of a received signal in receiver module 46.
  • [0059]
    Transmitter module 48 conditions output signals for wireless transmission to a medical device via antenna 38. For example, DSP 42 may generate timed output signals based on a selected communication mode in order to communicate with the respective medical device 8 via telemetry. Transmitter module 48 can receive signals from DSP 42 and amplify the signals for transmission via antenna 38. For example, transmitter module 48 may include transmit circuitry for driving antenna 38, such as a set of field effect transistors (FET) that output relatively large output voltage pulses in response to relatively small input voltages received from DSP 42. Transmitter module 48 may also include various other filters, amplifiers, or the like, that may be selectively activated based on the given communication mode. For example, in some cases, a selected communication mode identified by DSP 42 can cause DSP 42 to send control signals to transmitter module 48 to configure transmitter module 48 for telemetric communication consistent with the selected communication mode. In any case, transmitter module 48 conditions output signals from DSP 42 for wireless telemetric transmission to a medical device.
  • [0060]
    DSP 42 of programmer 5 may include several different bandpass filters and several different demodulators, such as one or more amplitude demodulators, one or more frequency-shift keyed (FSK) demodulators, one or more phase-shift keyed (PSK) demodulators, and the like. For example, these different components may be programmed as software or firmware. In any case, DSP 42 selects the particular bandpass filter(s) and demodulator type to process the digitized signal according to the communication mode that is selected. In other words, DSP compares the raw signal that is received to signatures in order to identify the appropriate communication mode, and then selectively enables the appropriate demodulator so that subsequent signals can be demodulated and interpreted.
  • [0061]
    An additional function implemented by DSP 42 may include the control of a variable-gain amplifier (VGA) or other components included in receiver module 46 or transmitter module 48. For example, this may further ensure that the receiver module 46 supplies to the A/D converter of DSP 42 a signal having a desired peak amplitude. Moreover, VGA control in the DSP 42 may provide flexibility in software so that adjustments can be made to properly condition a wide variety of telemetry signals.
  • [0062]
    In order to facilitate the automatic gain control (AGC) between DSP 42 and receiver module 46, receiver module 46 may include a digital-to-analog (D/A) converter to convert a digital control word supplied from DSP 42 to a corresponding analog voltage level for variable-gain amplification.
  • [0063]
    One specific configuration of programmer 5 may be formed of the exemplary components listed above including the TI-TMS320LC2406 DSP, SanDisk memory module, a dual coil planer antenna, a sufficiently small battery, and individual hardware components to implement the receiver module 46 and transmitter module 48. In that case, programmer 5 may realize a compact form factor suitable for inconspicuous use by a patient, e.g., to collect information from a medical device and send the memory cards to the physician. A minimal amount of communication from programmer 5 to the medical device may prompt the medical device to uplink the requested information. For example, such exemplary components may be used to realize a programmer 5 having dimensions less than approximately 60 millimeters by 90 millimeters by 15 millimeters. In other words, programmer 5 can be made to dimensions corresponding roughly to the size of a thick credit card. Such reduced size can be particularly useful for wearable embodiments of programmer 5.
  • [0064]
    If desired, programmer 5 may also include an activation switch (not shown), to allow a patient to initiate communication with a medical device. For example, if the patient identifies pain or other problems, it may be desirable to initiate communication, e.g., to cause the medical device to communicate sensed information to programmer 5. In that case, an activation switch can provide the patient with the ability to ensure that sensed conditions are stored in programmer 5 during periods of time when physical problems may be occurring to the patient.
  • [0065]
    Moreover, programmer 5 may include other user interface features, such as a display screen, a speaker, or a blinking light. For example, feedback in the form of sound or light flashes, images, instructions, or the like may be useful to a patient, e.g., to indicate that communication has been initiated or to indicate to the patient that the programmer is positioned correctly for such communication.
  • [0066]
    FIGS. 5 and 6 are diagrams illustrating one embodiment of programmer 5 in the form of an adhesive patch. In that case, programmer 5 may include an adhesive strip 51 for attaching programmer 5 to a patient's skin. In addition, electrodes 55 may also be used to facilitate the reception of signals though the patients flesh, although the use of electrodes would not be necessary for every embodiment. In other words electrodes 55 may provide an alternative to antenna 52 for the transmission and reception of signals. Accordingly, both electrodes 55 and antenna 52 may be electrically coupled to control unit 34.
  • [0067]
    Programmer 5 (in this case a patch) is configured to dynamically select different communication modes according to the communication modes presented from medical devices 8. As illustrated, programmer 5 may include an antenna 52, a control unit 34, a memory 36, and a power supply 38, an adhesive strip 51, a protective sheath 53 and electrodes 55.
  • [0068]
    Antenna 52 may comprise a coplanar dual coil antenna that sends and receives electromagnetic telemetry signals as directed by control unit 34. Alternatively or additionally, electrodes 55 may be used to send and receive the signals. The protective sheath 53 may substantially encapsulate one or more of the components of programmer 5.
  • [0069]
    As outlined above, programmer 5 (in this case a patch) supports communication according to a plurality of telemetry modes. Control unit 34 compares received signals with stored signatures by accessing memory 36. Then, after identifying an acceptable match between a stored signature and a received telemetry signal, programmer 5 is able to identify the telemetry technique associated with the medical device that sent the signal.
  • [0070]
    Memory 36 stores the signatures and may also store configuration parameters associated with different communication modes for control unit 34. In addition, memory 36 may include a lookup table (LUT) that maps signatures to communication modes, i.e., by mapping a number associated with a signature to a number associated with an associated communication mode. Thus, upon identifying a signature associated with a received telemetry signal, control unit 34 can access the LUT in memory 36 to select the proper communication mode. Then, control unit 34 can be configured according to the selected communication mode to output telemetry signals that the medical device associated with the received telemetry signal can understand. In addition, control unit 34 can configure itself so that signals sent from the respective device can be properly demodulated and interpreted.
  • [0071]
    As mentioned above, memory 36 may comprise a removable memory card. Accordingly, memory 36 may be removed from programmer 5, such as via a slot or hole formed in sheath 53. Alternatively, sheath 53 may be pulled back to expose memory 36, allowing memory 36 to be removed or replaced and possibly sent to a physician for analysis.
  • [0072]
    In still other embodiments, programmer 5 may be embodied in a wrist watch, a belt, a necklace, a pendent, a piece of jewelry, an adhesive patch, a pager, a key fob, an identification (ID) card, a laptop computer, a hand-held computer, or other mechanical configurations. A programmer 5 having dimensions less than approximately 60 millimeters by 90 millimeters by 15 millimeters can be particularly useful for wearable embodiments. In particular, a configuration similar that that illustrated in FIGS. 5 and 6 using the exemplary components listed herein may be used to realize a programmer with a small enough form factor to facilitate different wearable embodiments. Additional components may also be added, such as a magnet or electromagnet used to initiate telemetry for some devices.
  • [0073]
    FIG. 7 is a flow diagram illustrating a technique consistent with the principles of the invention. As shown, programmer 5 receives a telemetry signal 12 from a medical device 8 (71). Control unit 24 of programmer 5 selects a communication mode based on the received signal (72). Programmer 5 then communicates with medial device 8 using the selected communication mode (73).
  • [0074]
    In order to select the proper communication mode based on the received signal (72), control unit 24 of programmer 5 may identify a signature associated with the received signal. More specifically, receiver module 46 conditions a received telemetry signal so that it falls within the dynamic range of DSP 42. DSP 42 samples the conditioned signal and compares the digital sample to various signatures stored in memory 36. For example, DSP 42 may perform a correlation operation to compare a digital sample of a received signal to various signatures stored in memory 36. In particular, the correlation operation may compare the frequencies, phase shifts, pulse widths, or any other variable between the digital samples of the received signal to those of the different signatures. Upon identifying a signature that matches the digital sample of the received signal to within an acceptable degree (which may also be programmable), DSP 42 can configure programmer 5 according to a communication mode associated with the signature. In other words, once the appropriate signature has been identified, DSP 42 can select a communication mode, such as by accessing a LUT in memory 36 that maps signatures to communication modes.
  • [0075]
    Upon identifying the necessary communication mode for telemetric communication with a respective medical device 8, control unit 34 configures for such communication. For example, DSP 42 may select an appropriate set of bandpass filters and an appropriate demodulator, each of which may be software implemented as part of DSP 42. In addition, in some cases, DSP 42 may send control signals to receiver module 46 and transmitter module 48 to configure those modules 46, 48 for respective reception and transmission consistent with the selected communication mode. In this manner, programmer 5 can be configured for communication according to a first telemetric mode of communication, and then reconfigured for communication according to a second (different) telemetric mode of communication. In some cases, a large number of different communication modes can be supported by programmer 5.
  • [0076]
    FIG. 8 is another flow diagram illustrating a technique consistent with the principles of the invention. As shown, programmer 5 initiates telemetry with a medical device 8 (81). In most cases, in order to preserve battery life in a medical device, the medical device does not send telemetry signals unless it receives a request for such signals. Accordingly, programmer 5 can be configured to initiate telemetry with medical devices (81) by sending an appropriate request. Moreover, since the initiation required to cause a given medical device to send a telemetry signal may differ with the device, programmer may perform a plurality of initiation techniques so as to cause any device supported by programmer 5 to send a telemetry signal.
  • [0077]
    For some devices, a magnetic field may be used to initiate telemetry, such as by magnetically activating a switch on the respective device to cause the device to send telemetry signals. Accordingly, programmer 5 may include a magnet or an electromagnet that generates the required magnetic field to cause the medical device to send a telemetry signal. For other devices, telemetry from a medical device 8 may begin upon receiving a particular wireless signal that corresponds to a request for telemetry. Accordingly, control unit 24 of programmer 5 may be configured to send one or more different request signals to provoke a response from the medical device. In some cases, control unit 24 may send different request signals over time to provoke responses from different medical devices for which programmer 5 supports telemetry. Thus, if a particular device is in proximity to programmer 5, eventually the appropriate request signal will be sent from programmer 5 to that device.
  • [0078]
    In any case, once programmer 5 has initiated telemetry with the medical device (81) causing the medical device to send a telemetry signal, programmer 5 receives the signal from the medical device (82). Control unit 24 of programmer 5 identifies a signature stored in memory 26 that correlates with the received signal (83). More specifically, DSP 42 generates a digital sample based on a signal conditioned by receiver module 46, and compares the digital sample to the signatures stored in memory by invoking a correlation operation.
  • [0079]
    Upon identifying a signature stored in memory 26 that correlates with the received signal (83), control unit 24 identifies a medical device associated with the signature (84). More specifically, DSP 42 accesses a LUT in memory 26 which maps signatures to communication modes, and selects from the LUT, the communication mode associated with the identified signature.
  • [0080]
    Control unit 24 then configures programmer 5 for communication with the medical device 5 according to the selected communication mode (85). More specifically, DSP 42 selects particular bandpass filter(s) and a demodulator to process received telemetry signals in accordance with the communication mode that is selected. In addition, DSP 42 may send control signals to one or more components included in receiver module 46 or transmitter module 48 to configure the modules to condition received signals and to condition output signals according to the communication mode that is selected.
  • [0081]
    Programmer 5 can then telemetrically communicate with the medical device (86). This telemetric communication may be used for any of a wide variety of desirable communication that can occur between a programmer and a medical device. For example, programmer 5 may telemetrically communicate with the medical device to program a new therapy technique into the medical device. In particular, device 5 may be configured to receive input from a physician or medical personnel specifying a therapy to be performed, and may send a signal to the medical device according to the selected communication mode to direct the medical device to perform the therapy.
  • [0082]
    Alternatively, programmer 5 may telemetrically communicate with the medical device 8 to request stored information corresponding, for example, to diagnostic information, sensed conditions associated with the patient, information relating to therapy delivered to the patient, or any other information collected or identified by the medical device. In that case, programmer 5 may receive the requested information from the medical device in response to the request for stored information sent according to the appropriately selected communication mode. These or other communications may occur between a medical device and programmer 8 once programmer has identified the appropriate communication mode, and configured according to that communication mode consistent with the principles of the invention.
  • [0083]
    FIG. 9 is a conceptual diagram illustrating an alternative embodiment utilizing the multi-mode programmer 5 of the present invention communicating with an exemplary medical device 8 implanted in a human body 10 and, additionally, communicating to an external remote monitor that may be connected to a network (in a hospital or clinic) or to the Internet for long distance remote monitoring. This embodiment illustrates a system that allows the retrofitting of the existing implant base of near field telemetry pacemakers and defibrillators (totaling several million devices implanted worldwide) to be simply, inexpensively and with no patient trauma updated to a far field telemetry system to allow the remote monitoring of this group of patients. Implantable medical device 8 represents one of a variety of medical devices that may communicate with programmer 5. Although illustrated as an implantable cardiac pacemaker, medical device 8 may take the form of a variety of other medical devices such as, for example, an implantable defibrillator, an implantable pacemaker/cardioverter/defibrillator, an implantable muscular stimulus device, an implantable brain stimulator, an implantable nerve stimulator, an implantable drug delivery device, implantable monitor, or the like. Multi-mode programmer 5 may take the form of a belt worn pager like device, a pendant worn around the patient's neck, a wrist worn watch like device, a tape-on patch-like device or any other form factor that allows improved patient comfort and safety for long term monitoring.
  • [0084]
    In the example shown in FIG. 9, medical device 8 includes a hermetically sealed enclosure 14 that may include various elements, although the invention is not limited to hermetically sealed devices. By way of example, enclosure 14 may house an electrochemical cell, e.g., a lithium battery, circuitry that controls device operations and records sensed events, physiological activity and patient conditions, and a control unit coupled to an antenna to transmit and receive information via wireless telemetry signals 12.
  • [0085]
    Programmer 5 communicates with medical device 8 via near field telemetry signals 12—as substantially described in U.S. Pat. No. 4,556,063 to Thompson, et al. and U.S. Pat. No. 5,127,404 to Wyborny, et al. and incorporated herein by reference in their entireties. For example, programmer 5 may use telemetry signals 12 to program medical device 8 to deliver a particular therapy to human body 10, such as electrical stimulation, drug administration or the like. In addition, medical device 8 may use telemetry signals 12 to send information to programmer 5 such as diagnostic information, sensed conditions associated with the patient, information relating to therapy delivered to the patient, or any other information collected or identified by medical device 8. In this manner, telemetry allows communication between medical device 8 and programmer 5. Additionally programmer 5 communicates to the remote monitor device 7 via far field telemetry signals 3—as substantially described in U.S. Pat. No. 5,683,432 to Goedeke, et al. and incorporated herein by reference in its entirety. For example, the system described in association with FIG. 9 may allow remote monitoring of high-risk CHF or arrhythmia patients as substantially described in U.S. Pat. No. 5,752,976 “World Wide Patient Location and Data Telemetry System for Implantable Medical devices” to Duffin et al. and incorporated herein by reference in its entirety.
  • [0086]
    FIG. 10 is a simplified schematic representation of a software based multi-mode transmitter/receiver/programmer of the present invention. The design of programmer 5 consists of a single chip digital signal processor (DSP) 100. Examples of suitable DSPs include the TI-TMS320C2000 family of DSPs; such as the model number TI-TMS320LC2406 DSP, commercially available from Texas Instruments Incorporated of Dallas Tex., USA. By way of example, the oscillator 118 may comprise a 40 MHz crystal, although other oscillators could be used. The TI-TMS320LC2406 DSP is a 16-bit fixed point DSP, low cost ($3), fully static with low power modes originally designed for motor control applications. The TI-TMS320LC2406 DSP includes internal flash memory and a 16 channel 10-bit analog to digital converter (ADC) with 2Ms/s capability. Other DSPs and programmable microprocessors, however, could alternatively be used.
  • [0087]
    Continuing, FIG. 10 shows the unique antenna scheme within the programmer head as substantially described in U.S. Pat. No. 6,298,271 “Medical System Having Improved Telemetry” to Weijand incorporated herein by reference in its entirety. The antenna scheme utilizes a first antenna 102 and a second antenna 104, the antennas disposed in a concentric and co-planar manner. The smaller area antenna 104 (in this exemplary case the area of antenna 104 is the size of antenna 102) contains 4 times the number of turns of the larger antenna 102. This concentric and co-planar disposition permits the cancellation of far field signals (i.e., noise) and the reception of near field differential signals. It also permits the multi-mode programmer or peripheral memory patch to be of much smaller and, thus, a more portable size than was previously possible. Additionally, the antenna design results in a significant reduction in circuit design complexity. Low noise, wide band amplifiers 106, 108, 110 and 112 amplify the received antenna signals and input them to the DSP 100 ADC inputs for sampling. Downlink drivers 114 and 116 under control of DSP 100 provide downlink telemetry to an implanted medical device 8 (FIG. 1). Optionally, the SPI bus interface 122 and removable memory 120 may be added for a peripheral memory embodiment.
  • [0088]
    FIG. 11 is a schematic diagram of the front-end receiver, transmitter coil interface and DSP portions of the multi-mode programmer 5 according to an embodiment of the invention. The antenna system consists of 2 coils—an outer, larger coil 102 and an inner, smaller coil 104. Inner coil 104 has a larger number of turns than outer coil 102 to match the inductance of the 2 coils. The difference signal from the 2 coils allow a near field telemetry signal to be received while rejecting far field noise signals as described in U.S. Pat. No. 6,298,271 to Weijand and incorporated herein by reference in its entirety. Fixed gain amplifiers 106, 108, 110 and 112 amplify the received signal and provide 4 analog signal channels to the DSP ADC inputs (described below). Capacitors 113 and 115 and driver switches 114 and 116 control the downlink transmission to an implantable medical device 8. Independent control of the switches 114 and 116 by the DSP 100 allow non-overlap switch control. The circuit of FIG. 11 is powered by a battery and may include an optional voltage regulator (both not shown).
  • [0089]
    The DSP 100 contains 16-channel, 10 bit analog to digital converter (ADC) with independent ADC controller that samples and digitizes the 4 analog signals from amplifiers 106, 108, 110 and 112. The MAC processor under control of instructions contained in embedded memory in the DSP 100 processes, filters and demodulates the data samples received from the antenna system 102/104 from any of a large variety of conventional implantable devices. For ease of understanding, reference is made to the block diagram of FIG. 12, which depicts these software functions in equivalent hardware blocks.
  • [0090]
    FIG. 12 is a diagram of the uplinked RF telemetry signal from an implanted medical device showing one embodiment of ping detection and demodulation. The received and amplified signals are selected by multiplexer 152 and inputted to ADC 154 where they are converted at a rate of 700 kHz; the signal path is split into separate processing for odd and even samples. The odd 156 and even 158 correlators correlate the signal with an exponentially decaying sinusoid similar to the uplink pulse as described in the aforementioned '063 patent. As the correlator coefficients are zero every other sample (175 Khz signal sampled at 700 kHz) the odd and even correlators are just half the size of the full correlator. The results are absolute valued and summed 160 before being downsampled at 87.5 kHz (162) and filtered in FIR filter 164. Further processing detects peak and zero crossings 166 and frame and data decoding 168.
  • [0091]
    FIG. 13 is a diagram of an uplinked RF signal 200 showing a zero crossing extrapolation (FIG. 12 processing block 166) according to an embodiment of the invention. ADC samples are shown at 202, 204, 206, 208 and 210. Ground potential or zero signal value is denoted at 212. The extrapolated time of the zero crossing may be determined by the value (AD/AC)* time in uSec from sample 206 to 208. This extrapolation allows a reduced ADC sample rate and thus a reduced battery power drain.
  • [0092]
    Additional power reduction concepts may be utilized individually or in tandem. Specifically, the TI DSP has reduced power states that may be enabled during circuit inactivity. Additionally, the timing of many IMD uplink telemetry systems are crystal controlled allowing the system of FIG. 11 to be powered down into a sleep mode and awakened during a window of expected or possible uplink signal transmission. FIG. 14 shows an uplinked RF damped sinusoid 230 from a typical pulse position modulation system from an IMD. The DSP of FIG. 11 powers down after pulse reception and awakens, opening a window 234 of a discrete length, enabling the ADC to begin sampling the signal 232 received by the antenna. After the detection of 2 cycles of the pinged signal (at 236) the ADC conversion is disabled, conserving power. Lastly, the proper selection of the system clock allows the slowing down of the clock when low speed processing is required.
  • [0093]
    A further additional embodiment of multimode programmer system 5 as shown in FIGS. 5 and 6 above would include the use of the telemetry antenna 32 and DSP 42 to allow the recharging of a rechargeable battery 38 in a battery powered system. The full control of the coil switches (114 and 116 of FIG. 11A) allows the software to control battery recharging. The charging is accomplished by using the telemetry coil to receive a magnetic field at the frequency of the tuned antenna 102. The software detects the system basic frequency and adjusts the timer to drive the switches for synchronous rectification. The DSP's ADC is used for battery voltage monitoring and charge control.
  • [0094]
    The motor controller DSP based programmer of the present invention can eliminate the need for multiple programmers for telemetric communication with different medical devices. A multi-mode programmer of the present invention can be used to communicate with a plurality of different medical devices on a selective basis providing a universal programmer to minimize the programmers required to interrogate and program implantable devices from several manufacturers.
  • [0095]
    In addition, the invention may find useful application as an interrogator in emergency (first responder and emergency room) scenarios by facilitating the ability to identify and communicate with medical devices used by a given patient. In that case, the ability to obtain diagnostic and therapeutic information from a given medical device without requiring knowledge of the make and model of the device may save valuable time, possibly saving lives. In this embodiment, the programming of all parameters may not be available but universal safety modes may be programmed (such as emergency VVI). The interrogator of the present invention would downlink a command to the implanted device to cause an uplink telemetry transmission that would include the manufacturer, device model number, serial number, device status, diagnostic data, programmable parameters and contact information, if present.
  • [0096]
    The device of the present invention coordinates the function and operation of 2 or more implanted medical devices from the following list; pacemaker, implantable cardioverter/defibrillator (ICD), drug pump, neuro stimulator, drug pump or insertable loop recorder (ILR).
  • [0097]
    Specifically, the co-coordinator of the present invention may coordinate and/or synchronize the therapy of a pacemaker and ICD (providing improved detection, threshold reduction and/or improved efficacy), a ICD and drug pump (pain suppression prior to, or during, therapy delivery and/or threshold reduction), ICD and neuro stimulator (initiate pain suppression prior to, or during high voltage therapy delivery), pacemaker and ILR (improved detection utilizing both sense detectors), ICD and ILR (improved detection utilizing both sense detectors), and remote sensor to IMD including pacemaker, ICD, ILR, neuro stimulator or drug pump to aid in detection. The synchronization of the 2 or more devices may also provide protection for a non therapy-delivering device, preventing damage during high voltage stimulation.
  • [0098]
    The coordinator is preferably constructed as a transcutaneously applied simple, disposable, inexpensive patch implementation as substantially described herein above with respect to the apparatus and methods of FIGS. 4-14.
  • [0099]
    The coordinator may be used on a patient who already has an implanted medical device such as a pacemaker (i.e., rate responsive, single chamber, dual chamber, 3 chamber cardiac resynchronization, or the like), defibrillator (i.e., ventricular, atrial, with cardiac resynchronization, or the like), cardiac monitor (i.e., ILR), drug pump or neuro stimulator. If the patient's disease state progresses or deteriorates, the clinician often wants to upgrade the therapy device to add additional capabilities. Often the need for a second therapy device may only be temporary such as for a few weeks or months. As an example, cardiac patients may progress to epileptic seizures that ultimately are controllable by drugs/medicants. Alternatively, epilepsy often progresses to cardiac anomalies that may require temporary cardiac therapies such as an ILR or defibrillator. In these patients the need for temporary expanded system is required for several days, weeks or months to allow the physician to titrate the appropriate drug regime for control of the cardiac or neural anomaly. To date, the only way to upgrade therapy is to replace the implanted device with a device of increased capabilities.
  • [0100]
    The physician may choose to retain the existing IMD, add a second implanted device and the inventive device to coordinate the function of the 2 IMD systems. Upon the implant of a second device, the physician attaches the coordinator patch and programs the 3 devices with programmer 5. The coordinator patch utilizes a telemetry link between itself and the 2 IMDs to allow the sensing of cardiac events, determines the appropriate therapy to be delivered and, again via the telemetry links, cause a course of therapy to be delivered by the appropriate IMD or, alternatively, by both IMDs. The telemetry links may consist of similar frequencies and modulation types or, alternatively, may be entirely different telemetry formats as described herein above.
  • [0101]
    FIG. 15 is a simplified schematic view of the present invention showing an IMD 14 implanted in a patient 10. IMD 14 may be a pacemaker or ICD connected to the patient's heart 20 via endocardial or epicardial leads 22 (representative right ventricular (RV) and coronary sinus (CS) leads shown in FIG. 15). Additionally, a neuro stimulator 16 is also implanted in patient 10. A brain stimulation lead 24 is shown connected to stimulator 16. Alternatively, a vagal nerve stimulation lead 26 is shown in FIG. 15. In yet another alternative embodiment IMD 16 may be a drug pump for delivery of a medicant through a catheter (not shown in FIG. 15) to the brain, spinal cord or another organ.
  • [0102]
    A multi-mode programmer 12 is shown which may be used to program IMD 14 and/or neuro stimulator/drug pump 16 via a 2-way wireless telemetry communication link 28. Additionally, stored diagnostic data may be uplinked and evaluated by the patient's physician utilizing programmer 12 via 2-way telemetry link 28. The wireless communication link 28 may consist of an RF link (such as described in U.S. Pat. No. 5,683,432 “Adaptive Performance-Optimizing Communication System for Communicating with an Implantable Medical Device” to Goedeke, et al. and incorporated herein by reference in its entirety). A coordinator 18 is shown attached to the patient's 10 chest and allowing 2-way communication to IMD 14 and neuro stimulator 16 via 2-way communication link 30. The wireless communication link 30 may consist of an RF link (such as described in the above referenced Goedeke '432 patent), an electromagnetic/ionic transmission (such as described in U.S. Pat. No. 4,987,897 “Body Bus Medical Device Communication System” to Funke and incorporated herein by reference in its entirety) or acoustic transmission (such as described in U.S. Pat. No. 5,113,859 “Acoustic Body Bus Medical Device Communication System” to Funke and also incorporated herein by reference in its entirety). An external patient activator (not shown in FIG. 15) may optionally allow the patient 10, or other care provider (also not shown in FIG. 15), to manually activate the recording of diagnostic data or activate therapy delivery.
  • [0103]
    In operation, the system of FIG. 15 monitors cardiac signals and function via cardiac contacting leads 22 and IMD 14 and brain signals via brain lead 24 and neuro stimulator 16. The coordinator 18 receives the sensing of cardiac or brain signals via telemetry 30 from IMD 14 and stimulator 16. Coordinator 18 monitors sensed cardiac signals for cardiac arrhythmic abnormalities including sinus arrhythmia, sinus pause, premature atrial contraction (PAC), premature ventricular contraction (PVC), irregular rhythm (wandering pacemaker, multifocal atrial tachycardia, atrial fibrillation), asystole or paroxysmal tachycardia) from IMD 14 and, upon abnormality detection, initiates brain stimulation via stimulator 16 and lead 24 to suppress an onset of an epileptic seizure. Note that sensed cardiac events may also include conduction abnormalities including AV-block (AVB), bundle branch block (BBB) and repolarization abnormalities including T-wave inversion and ST-elevation or depression. Lastly, hypertension, hypotension and vaso-vagal syncope (VVS) are common in epilepsy patients and may be monitored by IMD 14.
  • [0104]
    Alternatively, coordinator 18 may sense the onset of a seizure and initiate preventive cardiac stimulation (such as, bradycardia pacing, overdrive pacing, anti-tachycardia pacing (ATP), cardioversion, defibrillation shock, etc.) to suppress cardiac arrhythmia onset. In an alternative embodiment, coordinator 18 may initiate diaphragmatic stimulation from IMD 14 via leads not shown in FIG. 15 or, alternatively, vagal stimulation via leads 26 to prevent pulmonary events such as obstructive sleep apnea (OSA), central apnea, and/or neurogenic pulmonary edema.
  • [0105]
    In operation, coordinator 18 receives notice of a sensed arrhythmia or cardiac anomaly via telemetry link 30 from IMD 14 and initiates therapy from neuro stimulator or drug pump 16 or, alternatively, from IMD 14 via telemetry link 30. In an alternative embodiment, coordinator 18 receives notice of a sensed epileptic seizure or neuro anomaly via a telemetry link 30 from neuro stimulator/drug pump 16 and initiates therapy from IMD 14 or, alternatively, from neuro stimulator or drug pump 16 via telemetry link 30. In the above descriptions, telemetry link 30 may be an identical link between the coordinator 18 and IMD 14 and neuro stimulator/drug pump 16 or, alternatively, the 2 telemetry links may be different as described herein above.
  • [0106]
    Optionally, coordinator 18 may contain a push button 19 to allow the patient 10 to communicate some event to the IMDs 14 and 16 such as the onset of an arrhythmia, the feeling of light-headedness, the beginning of a meal, chest pains, to manually activate diagnostic data recording, initiate therapy delivery and the like. Coordinator 18 communicates the closing of push button 19 to either or both of the 2 IMDs 14 and 16 via telemetry link 30.
  • [0107]
    Coordinator 18 may be implemented in any number of mechanical configurations such as wearable configurations such as jewelry, a wristwatch or a belt buckle to be worn by the patient or medical personnel or, preferably, an adhesive patch as described above in relation to FIG. 5 and FIG. 6.
  • [0108]
    The coordinator 18 may alternatively provide protection for an low voltage IMD such as a pacemaker, neuro stimulator, drug pump, ILR from a high voltage shock from an ICD by opening the lead connection, the low voltage stimulus circuitry and/or the sense amplifier input circuitry just prior to the delivery of the shock. After delivery of the high voltage shock, the lead connection, low voltage stimulus circuitry and/or the sense amplifier input circuitry are reconnected and the low voltage device returns to normal operation.
  • [0109]
    FIG. 16 is a diagram 300 of a method of implementing the implantation of a second IMD, initiating communication between a first and second IMD and initiating system control of the enhanced system consisting of the 2 IMDs and coordinator. At step 302, the physician implants a second IMD into a patient 10 who already has a first IMD. The physician attaches coordinator 18 to the patient 10 at step 304 and initializes the coordinator. At step 306, the coordinator interrogates the 2 IMDs, receives model and serial number information, and sets up telemetry communication between itself and the 2 IMDs. At step 308, the coordinator initializes enhanced system function utilizing information from the 2 IMDs and a program stored in its memory. At step 310, the enhanced system operation continues per the program instructions and programs stored in the coordinator memory 36 of FIG. 5.
  • [0110]
    Alternatively at step 306, the physician could select the telemetry communication modes and program the coordinator 18 with the appropriate commands via programmer 12 to enable the telemetry links 30 to each of the IMDs and the flow diagram continuing with steps 308 and 310 as above.
  • [0111]
    An alternative embodiment would allow an implanting physician to implant a sensor unit at a remote location in the patient, which would transmit data to a therapy or diagnostic IMD via coordinator 18. The sensor unit may include an accelerometer, pressure, O2sat, pH, flow, dP/dt, acoustic (sound), Doppler ultrasound, impedance plethsymmography, piezo-electric, or the like, sensors located remote from the IMD implant site. Coordinator 18 would facilitate the transfer of data from the sensor to the IMD to allow improved detection and/or store diagnostic data for later review by the patient's physician.
  • [0112]
    A number of embodiments and features of an implantable medical device coordinator 18 have been described. The coordinator 18 may take a variety of forms and mechanical configurations in addition to those described herein. Moreover, the techniques described herein may be implemented in the inventive device in hardware, software, firmware, or any combination thereof. If implemented in software, the invention may be directed to a computer readable medium comprising program code, that when executed, performs one or more of the techniques described herein. For example, the computer readable medium may comprise a random access memory (RAM), SDRAM, FLASH, or possibly a removable memory card as outlined herein. In any case, the memory stores the computer readable instructions that, when executed cause coordinator 18 to carry out the techniques described herein. These and other embodiments are within the scope of the following claims.
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Classifications
U.S. Classification607/60, 607/32, 128/903
International ClassificationH04B1/40, H04B1/38, A61N1/36, A61N1/372
Cooperative ClassificationH04B1/385, A61N1/37252, H04B1/401, Y10S128/903
European ClassificationA61N1/372D8