U.S. patent application number 11/554212 was filed with the patent office on 2007-03-08 for multi-mode coordinator for medical device function.
Invention is credited to Daniel R. Greeninger, David L. Thompson, Koen J. Weijand.
Application Number | 20070055324 11/554212 |
Document ID | / |
Family ID | 34652652 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070055324 |
Kind Code |
A1 |
Thompson; David L. ; et
al. |
March 8, 2007 |
Multi-mode coordinator for medical device function
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.
Inventors: |
Thompson; David L.;
(Andover, MN) ; Weijand; Koen J.; (Alfas Del Pl,
ES) ; Greeninger; Daniel R.; (Coon Rapids,
MN) |
Correspondence
Address: |
MEDTRONIC, INC.
710 MEDTRONIC PARK
MINNEAPOLIS
MN
55432-9924
US
|
Family ID: |
34652652 |
Appl. No.: |
11/554212 |
Filed: |
October 30, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10722891 |
Nov 26, 2003 |
|
|
|
11554212 |
Oct 30, 2006 |
|
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|
Current U.S.
Class: |
607/60 ; 128/903;
607/32 |
Current CPC
Class: |
H04B 1/401 20130101;
Y10S 128/903 20130101; G16H 40/63 20180101; H04B 1/385 20130101;
G16H 20/30 20180101; A61N 1/37252 20130101; A61N 1/37254
20170801 |
Class at
Publication: |
607/060 ;
128/903; 607/032 |
International
Class: |
A61N 1/36 20060101
A61N001/36 |
Claims
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, O.sub.2sat, 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
1/4 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, O.sub.2sat, 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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