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Medical Patent Abstract
An integrated device for remote monitoring of implanted medical
devices and surface ECG information includes components for collection
of information from an implanted medical device, collection of surface
ECG information, and remote communication of the collected information
to a remote monitoring station. The remote monitoring station controls
operation of the integrated device to automatically acquire the
information without substantial patient intervention. In this manner,
the device promotes accurate and timely collection of the information,
and reduced depletion of battery resources within the implanted
medical device.
Medical Patent Claims
What is claimed is:
1. A patient monitoring device comprising: a telemetry interface
to collect device information from an implanted medical device within
a patient; a surface electrocardiogram (ECG) interface to collect
surface ECG information from the patient simultaneously with collection
of the device information and to provide synchronization markers
with the collected surface ECG information that identify a time
period when the ECG information and the device information are being
collected simultaneously, to allow synchronization of the device
information with the surface ECG information; and a telecommunication
interface to transmit sequentially the surface ECG information and
the device information to a remote monitoring station.
2. The device of claim 1, wherein the telemetry interface includes
a radio frequency wand for placement in proximity with the implanted
medical device.
3. The device of claim 1, wherein the surface ECG interface includes
electrodes for placement on the patient.
4. The device of claim 3, further comprising wristbands that carry
the electrodes.
5. The device of claim 3, further comprising a telephone handset
that includes the surface ECG interface and the electrodes, wherein
the telephone handset communicates with the telecommunication interface.
6. The device of claim 5, wherein the telephone handset comprises
a mobile telephone handset.
7. The device of claim 3, wherein the telemetry interface includes
a radio frequency wand for placement in proximity with the implanted
medical device, the device further comprising a telephone handset
that integrates the wand, the surface ECG interface and the electrodes.
8. The device of claim 7, wherein the wand and the electrodes are
positioned on the handset to facilitate placement of the wand relative
to the implanted medical device and placement of the electrodes
in positions suitable for surface ECG monitoring when the handset
is placed in contact with an upper chest region of the patient.
9. The device of claim 1, wherein the telemetry interface includes
a radio frequency wand for placement in proximity with the implanted
medical device, the device further comprising a telephone handset
that integrates the wand.
10. The device of claim 9, wherein the telephone handset includes
the surface ECG interface and a connection terminal to receive surface
ECG electrodes.
11. The device of claim 10, wherein the ECG electrodes include
adhesive-backed electrodes for placement on the patient.
12. The device of claim 10, further comprising wristbands that
carry the ECG electrodes.
13. The device of claim 1, further comprising: a memory to store
the device information collected from the implanted medical device;
and a controller to selectively transmit the surface ECG information
and the stored device information to the remote monitoring station
via the telecommunication interface.
14. The device of claim 13, wherein the controller drives simultaneous
collection of the device information and the surface ECG information.
15. The device of claim 14, further comprising: a modem to transmit
the device information to the remote monitoring station; and a transtelephonic
frequency modulator to transmit the surface ECG information.
16. The device of claim 13, wherein the controller generates time
markers in response to collection of the device information, and
incorporates the time markers in the surface ECG information.
17. The device of claim 13, wherein the controller is responsive
to a control signal received from the remote monitoring station
via the telecommunication interface to drive collection and transmission
of the device information and the surface ECG information.
18. The device of claim 1, wherein the device information includes
device parameter information and internal electrogram information
obtained by the implanted medical device.
19. The device of claim 1, wherein the telecommunication interface
includes a public switched telephone network interface.
20. The device of claim 1, wherein the telecommunication interface
transmits the device information and the surface ECG information
to the remote monitoring station within a single telephone call
established by the telecommunication interface.
21. The device of claim 1, further comprising an output device
to present information communicated to the device by the remote
monitoring station.
22. A method comprising: collecting device information from an
implanted medical device within a patient; collecting surface electrocardiogram
(ECG) information from the patient simultaneously with the collecting
of the device information; providing synchronization markers with
the collected surface ECG information that identify a time period
when the ECG information and the device information are being collected
simultaneously to allow synchronization of the device information
with the surface ECG information; and transmitting sequentially
the surface ECG information and the device information to a remote
monitoring station via a common telephone interface.
23. The method of claim 22, further comprising transmitting the
device information and the surface ECG information to the remote
monitoring station in the course of a single telephone call.
24. The method of claim 22, further comprising collecting the device
information from the implanted medical device via a radio frequency
wand placed in proximity with the implanted medical device.
25. The method of claim 22, further comprising collecting the surface
ECG information via surface ECG electrodes placed on the patient.
26. The method of claim 25, further comprising collecting the surface
ECG information from wristbands that carry the electrodes.
27. The method of claim 25, further comprising collecting the surface
ECG information from a telephone handset that includes the surface
ECG electrodes, wherein the handset is placed on the patient to
cause contact between the surface ECG electrodes and the patient,
and wherein the telephone handset communicates with the telephone
interface.
28. The method of claim 27, wherein the telephone handset comprises
a mobile telephone handset.
29. The method of claim 27, further comprising collecting the device
information from the implanted medical device via a radio frequency
wand placed in proximity with the implanted medical device, wherein
the telephone handset integrates the wand and the electrodes.
30. The method of claim 29, wherein the wand and the electrodes
are positioned on the handset to facilitate placement of the wand
relative to the implanted medical device and placement of the electrodes
in positions suitable for surface ECG monitoring when the handset
is placed in contact with an upper chest region of the patient.
31. The method of claim 30, wherein the telephone handset includes
the surface ECG interface and a connection terminal to receive surface
ECG electrodes.
32. The method of claim 31, wherein the ECG electrodes include
adhesive-backed electrodes for placement on the patient, the method
further comprising adhering the electrodes to the patient.
33. The method of claim 31, further comprising attaching wristbands
that carry the ECG electrodes to the patient.
34. The method of claim 22, further comprising: storing the device
information collected from the implanted medical device in a memory;
and selectively transmitting the surface ECG information and the
stored device information to the remote monitoring station.
35. The method of claim 34, further comprising simultaneously collecting
the device information and the surface ECG information.
36. The method of claim 35, further comprising: transmitting the
device information to the remote monitoring station via a modem;
and transmitting the surface ECG information via a transtelephonic
modulator.
37. The method of claim 34, further comprising generating time
markers in response to collection of the device information, and
incorporating the time markers in the surface ECG information.
38. The method of claim 34, further comprising receiving a control
signal received from the remote monitoring station, and collecting
and transmitting the device information and the surface ECG information
in response to the control signal.
39. The method of claim 22, wherein the device information includes
device parameter information and internal electrogram information
obtained by the implanted medical device.
40. The method of claim 22, further comprising transmitting the
device information and the surface ECG information via a public
switched telephone network interface.
41. The method of claim 22, further comprising transmitting the
device information and the surface ECG information to the remote
monitoring station within a single telephone call.
42. The method of claim 22, further comprising presenting to the
patient information communicated to the device by the remote monitoring
station.
43. A patient monitoring system comprising: a remote monitoring
station; and a patient monitoring device including a telemetry interface
to collect device information from an implanted medical device within
a patient, a surface electrocardiogram (ECG) interface to collect
surface ECG information from the patient simultaneously with the
collection of the device information and provide synchronization
markers with the collected surface ECG information that identify
a time period when the ECG information and the device information
are being collected simultaneously to allow synchronization of the
device information with the surface ECG information, a telecommunication
interface to transmit sequentially the surface ECG information and
the device information to the remote monitoring station.
44. The system of claim 43, wherein the remote monitoring station
includes a transtelephonic interface to receive the surface ECG
information, and a modem interface to receive the device information.
45. The system of claim 43, wherein the remote monitoring station
includes a report generation module to present the surface ECG information
and the device information.
46. The system of claim 43, wherein the patient monitoring device
includes a telemetry interface having a radio frequency wand for
placement in proximity with the implanted medical device.
47. The system of claim 43, wherein the patient monitoring device
includes a surface ECG interface having electrodes for placement
on the patient.
48. The system of claim 47, further comprising a telephone handset
that includes the surface ECG interface and the electrodes, wherein
the telephone handset communicates with the telecommunication interface.
49. The system of claim 48, wherein the telephone handset comprises
a mobile telephone handset.
50. The system of claim 47, wherein the telemetry interface includes
a radio frequency wand for placement in proximity with the implanted
medical device, the device further comprising a telephone handset
that integrates the wand, the surface ECG interface and the electrodes.
51. The system of claim 43, wherein the patient monitoring device
includes: a memory to store the device information collected from
the implanted medical device; and a controller to selectively transmit
the surface ECG information and the stored device information to
the remote monitoring station via the telecommunication interface.
52. The system of claim 51, wherein the controller drives simultaneous
collection of the device information and the surface ECG information.
53. The system of claim 52, wherein the patient monitoring device
includes a modem to transmit the device information to the remote
monitoring station, and a transtelephonic modulator to transmit
the surface ECG information.
54. The system of claim 51, wherein the controller generates time
markers in response to collection of the device information, and
incorporates the time markers in the surface ECG information.
55. The system of claim 51, wherein the controller is responsive
to a control signal received from the remote monitoring station
via the telecommunication interface to drive collection and transmission
of the device information and the surface ECG information.
56. The system of claim 43, wherein the device information includes
device parameter information and internal electrogram information
obtained by the implanted medical device.
57. The system of claim 43, wherein the telecommunication interface
includes a public switched telephone network interface.
58. The system of claim 43, wherein the telecommunication interface
transmits the device information and the surface ECG information
to the remote monitoring station within a single telephone call
established by the telecommunication interface.
59. The system of claim 43, further comprising an output device
to present information communicated to the device by the remote
monitoring station.
Medical Patent Description
TECHNICAL FIELD
The invention relates to remote monitoring of medical patients
and implanted medical devices.
BACKGROUND
Implanted medical devices, such as pacemakers, typically include
wireless telemetry circuitry to permit monitoring and programming
of the device by an external monitor or programmer. In addition,
some monitors and programmers include a telecommunication interface
to communicate remotely with a remote monitoring station. In this
manner, some monitors and programmers support remote monitoring
and programming of implanted medical devices, e.g., via a dial-up
telephone connection or network connection.
Typically, to commence monitoring, a remote monitoring station
operator calls a patient and establishes a two-way telephone connection.
A person at the remote monitoring station guides the patient to
set up the connection, place surface electrodes on the patient's
chest for surface ECG recording, and turn on the monitor or programmer
to interrogate the pacemaker implanted within the patient. In particular,
the patient places a wand that contains a radio frequency (RF) antenna
in proximity with the implanted pacemaker.
The monitor or programmer receives data from the implanted pacemaker
and stores the data for communication to the remote monitoring station,
e.g., via a telephone or network connection. In addition, data collected
from the surface ECG recording is transmitted to the remote monitoring
station, typically using transtelephonic frequency modulation (FM).
Collection and transmission of implanted medical device data and
surface ECG data in this manner is useful in providing the remote
monitoring station with remote access to critical patient information.
Existing systems place great reliance, however, on the patient
to take certain actions in a timely and accurate manner. To ensure
accurate data recording, for example, the patient must be trained
to quickly and accurately position the wand and ECG monitoring electrodes.
If the patient is not sufficiently adept in handling wand or electrode
placement, interrogation may take longer than desired, possibly
resulting in undue depletion of the pacemaker battery.
Thus, inappropriate actions on the part of the patient can be a
significant problem in affecting longevity of a pacemaker. With
implantable cardioverter/defibrillators (ICD), it is even more important
to interrogate the device as well as assess surface ECG simultaneously.
Collecting the surface ECG recording in combination with retrieving
the contents of the implanted medical device can yield additional
clinical information in the assessment of the operation of the implanted
medical device.
SUMMARY
In general, the invention is directed to an integrated device for
remote monitoring of implanted medical devices and surface ECG information.
The integrated device includes components for collection of information
from an implanted medical device, collection of surface ECG information,
and remote communication of the collected information to a remote
monitoring station. In some embodiments, the remote monitoring station
controls operation of the integrated device to automatically acquire
the information without substantial patient intervention. In this
manner, the device promotes accurate and timely collection of the
information, and reduced depletion of battery resources within the
implanted medical device.
In one embodiment, the invention provides a patient monitoring
device comprising a telemetry interface to collect device information
from an implanted medical device within a patient, a surface electrocardiogram
(ECG) interface to collect surface ECG information from the patient,
a telecommunication interface to transmit the device information
and the surface ECG information to a remote monitoring station.
In another embodiment, the invention provides a method comprising
collecting device information from an implanted medical device within
a patient, collecting surface electrocardiogram (ECG) information
from the patient, and transmitting the device information and the
surface ECG information to a remote monitoring station via a common
telephone interface.
In an added embodiment, the invention provides a patient monitoring
system comprising a remote monitoring station, and a patient monitoring
device including a telemetry interface to collect device information
from an implanted medical device within a patient, a surface electrocardiogram
(ECG) interface to collect surface ECG information from the patient,
a telecommunication interface to transmit the device information
and the surface ECG information to the remote monitoring station.
The details of one or more embodiments of the invention are set
forth in the accompanying drawings and the description below. Other
features and inventive aspects of the invention will be apparent
from the description and drawings, and from the claims.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic illustration of an implantable medical device
with leads extending to a human heart.
FIG. 2 is a block diagram illustrating a system for remote communication
with a patient and an implanted medical device within the patient.
FIG. 3 is a diagram of a telephone handset forming part of a device
for remote monitoring of implanted medical devices and surface ECG
information.
FIG. 4 is a diagram illustrating placement of the telephone handset
of FIG. 3 over the chest of a patient.
FIG. 5 is a diagram of a wrist electrode arrangement forming part
of a device for remote monitoring of implanted medical devices and
surface ECG information.
FIG. 6 is a diagram of an alternative telephone handset with another
wrist electrode arrangement.
FIG. 7 is a block diagram illustrating the system of FIG. 2 in
greater detail.
FIG. 8 is a block diagram illustrating an integrated device, for
remote monitoring of implanted medical devices and surface ECG information,
forming part of the system of FIG. 2.
FIG. 9 is a block diagram illustrating operation of a remote monitoring
station forming part of the system of FIG. 2.
FIG. 10 is a chart illustrating collection of implanted medical
device information and surface ECG information.
FIG. 11 is a flow diagram illustrating a process for remote monitoring
of implanted medical devices and surface ECG information.
FIG. 12 is a flow diagram illustrating additional details of the
process of FIG. 10.
DETAILED DESCRIPTION
FIG. 1 depicts an exemplary implantable medical device (IMD) 10
with a patient 11. In accordance with the invention, an integrated
patient monitoring device is designed to collect device information
from IMD 10 via radio frequency (RF) telemetry, and surface ECG
information from patient 11 via surface electrodes. As will be described,
the integrated patient monitoring device includes a telecommunication
interface for remote transmission of the collected information to
a remote monitoring station. In some embodiments, the remote monitoring
station controls operation of the integrated device to automatically
acquire the information without substantial patient intervention.
IMD 10 delivers pacing pulses or other stimulation therapy to heart
12. In the example of FIG. 1, IMD 10 is an implantable, multi-chamber
pacemaker that includes cardioversion and defibrillation capabilities.
The invention is not limited to the particular IMD and configuration
shown in FIG. 1, however, but may be practiced with a variety of
implantable medical devices. The invention may be practiced, for
example, with IMDs that pace a single cardiac chamber or several
chambers, including one or more atria or one or more ventricles,
as well as IMDs that lack cardioversion and defibrillation capability.
IMD 10 includes an implantable pulse generator (IPG) to generate
pacing stimuli to administer one or more therapies to heart 12.
In the embodiment shown in FIG. 1, pacing stimuli are applied to
the right atrium 14 or the right ventricle 16, or both. IMD 10 also
includes circuitry to sense atrial and ventricular activations.
Atrial and ventricular bipolar pace/sense electrode pairs at the
distal ends of leads 18 and 20, respectively, carry out the pacing
and sensing functions. IMD 10 includes a housing 52 that may serve
as a "can" electrode. A connector block 24 receives proximal
ends of leads 18, 20.
In operation, IMD 10 senses and records EGM information obtained
via electrodes carried by leads 18, 20 and, optionally, the can
electrode provided by housing 22. IMD 10 stores the EGM information
and IMD parameters in a memory associated with the IMD. IMD 10 also
stores program instructions for delivery different pacing therapies
to heart 11. In addition, IMD 10 includes an RF telemetry interface
that permits programming of the IMD and interrogation of the IMD
to collect device information including the EGM information or IMD
parameters. The EGM information may be associated with particular
episodes recorded by IMD 10.
FIG. 2 is a block diagram illustrating a system 28 for remote communication
with patient 11 and IMD 10 within the patient. As shown in FIG.
2, system 28 includes a remote monitoring station 30 and a patient
monitoring device 32. Patient monitoring device 32 integrates features
for collection of device information from IMD 10 and collection
of surface ECG information from patient 11. In this manner, patient
monitoring device 32 performs dual functions in a single device,
providing the operator with convenience and simplicity. In addition,
in some embodiments, patient monitoring device 32 is responsive
to control signals transmitted by remote monitoring system 30.
As shown in FIG. 2, remote monitoring station 30 and patient monitoring
device 32 communicate with one another via public switched telephone
network (PSTN) 34. Patient monitoring device 32 includes a telephone
base station 36 including a telecommunication interface for communication
with PSTN 34. In the example of FIG. 2, patient monitoring device
32 includes a telephone handset 38 coupled to telephone base station
36, e.g., via a wired connection 37 or wireless connection.
Handset 38 includes an integrated RF telemetry wand 40 for communication
with IMD 10 to collect device information including EGM information
and device parameters. In addition, handset includes a surface ECG
interface to collect surface ECG information from ECG electrodes
44. ECG electrodes 44 are placed in contact with patient 11 to collect
ECG information.
Handset 38 communicates the collected information to telephone
base station 36, which then relays the information to remote monitoring
station 30 via PSTN 34. As will be described, telephone base station
36 transmits the surface ECG information using transtelephonic frequency
modulation (FM) in real time. Telephone base station 36 transmits
the device information using a data modem. The device information
and surface ECG information can be communicated during the course
of a single telephone call.
Remote monitoring station 30, in the example of FIG. 2, includes
a computer workstation 46 coupled to a transtelephonic interface
48 and a modem 50. Remote monitoring station 30 also includes a
telephone 52. A remote monitoring station operator uses telephone
52 to communicate with patient 11. For example, the operator initiates
a telephone call to patient 11 to guide the patient through set-up
procedures to establish a call for transfer of collected device
information and surface ECG information.
Transtelephonic interface 48 receives and demodulates the surface
ECG information transmitted by patient monitoring device 32. Modem
50 receives and demodulates the device information transmitted by
patient monitoring device 32. Computer workstation 46 processes
the demodulated surface ECG information and device information to
archive and display the information for review by an operator associated
with remote monitoring station 30. For example, computer workstation
46 may generate a patient database record containing the device
information and the surface ECG information.
Remote monitoring station 30 and patient monitoring device 32,
in some embodiments, coordinate transmission of device information
and surface ECG information. For example, patient monitoring device
32 is responsive to control signals transmitted by remote monitoring
station 30 to transmit surface ECG information in real time via
transtelephonic modulation. When a sufficient amount of surface
ECG information has been collected, patient monitoring device 30
transmits buffered device information to remote monitoring station
30.
In some embodiments, patient monitoring device 32 includes time
markers in the surface ECG information transmitted to remote monitoring
station 30. Patient monitoring device 32 generates the time markers
every few seconds to indicate that, during transmission of the surface
ECG information in real time, the device information continues to
be collected and buffered. In this manner, an operator associated
with remote monitoring station 30 can view the real time surface
ECG information and verify, by observing the time markers, that
patient monitoring device 32 is collecting the device information.
If the time markers are not present in the real-time surface ECG
information, the operator determines that patient monitoring device
32 is not collecting device information. In this case, the operator
may instruct patient 11, via the telephone interface, to more accurately
position handset 38 and wand 40 relative to IMD 10. Consequently,
the operator can verify accurate and timely collection of the device
information, and thereby avoid undesirable depletion of battery
resources within the implanted medical device. In particular, the
operator can reduce the number of ineffective data collection attempts,
and hence the number of power-draining telemetry sessions initiated
with IMD 10.
FIG. 3 is a diagram of a telephone handset 38 forming part of a
patient monitoring device 32. As shown in FIG. 3, handset 38 includes
a housing 56, a microphone 58, a speaker 60, and an RF telemetry
wand 62. Microphone 58 and speaker 60 may be entirely conventional
telephone components capable of transmitting and receiving voice
information. RF telemetry wand 62 is designed to communicate with
IMD 10 when placed in proximity with the IMD. Accordingly, handset
38 or telephone base station 36 includes appropriate telemetry interface
circuitry to drive RF telemetry wand 62 for communication with IMD
10. As an alternative, handset 38 may be entirely self-contained
in the form of a mobile telephone such as a cellular phone, personal
digital assistant, or other devices with wireless telecommunication
capabilities.
Handset 38 also includes a first set of surface ECG electrodes
64A, 64B (collectively electrodes 64) and a second set of electrodes
66A, 66B, 66C, 66D (collectively electrodes 66). Handset 38 obtains
surface ECG information sensed across electrodes 64, 66. Electrodes
64 may be coupled to one another. Similarly, electrodes 66 may be
coupled to one another. In this manner, electrodes 64 and 66 present
multiple electrode surfaces for contact with the chest of patient
11. As an alternative to electrodes 64, 66, handset 38 includes
a port 68 to receive an electrode cable coupled to external, adhesive-
or gel-backed surface electrodes (not shown in FIG. 3).
FIG. 4 is a diagram illustrating placement of the telephone handset
38 of FIG. 3 over the chest of a patient. As shown in FIG. 4, patient
11 places handset 38 against his chest in the proximity of heart
12 and IMD 10 in order to collect surface ECG information from the
chest and device information from the IMD. In particular, handset
38 places electrodes 64 and 66 in contact with the chest to obtain
the surface ECG information. In addition, handset 38 places RF telemetry
wand 62 in proximity with IMD 10, which may be implanted in the
upper chest area near one of the patient's clavicles, e.g., in a
subpectoral pocket. Thus, as illustrated in FIG. 4, handset 38 simplifies
the patient's task in placement of electrodes 64, 66 and RF telemetry
wand 62. The patient simply brings handset 38 into contact with
the chest near heart 12, and then commences collection of device
information and surface ECG information via RF telemetry wand 62
and electrodes 64, 66, respectively.
FIG. 5 is a diagram of a wrist electrode arrangement 77 forming
part of patient monitoring device 32. As shown in FIG. 5, wrist
electrode arrangement 77 includes wrist bands 70A, 70B carrying
electrodes 72A, 72B, respectively. A connector plug 73 is designed
to mate with port 68 in handset 38 to coupled electrodes 72A, 72B
to surface ECG interface circuitry within the handset. Cable 74
carries two conductors that are separated in bifurcator 75 to form
two cables 76A, 76B that are electrically coupled to electrodes
72A, 72B. In this manner, wrist electrode arrangement 77 serves
as an alternative means for collection of surface ECG information
from patient 11. If electrodes 64, 66 are ineffective in obtaining
the surface ECG information, for example, the operator of remote
monitoring station 30 may instruct patient 11 to instead use wrist
electrode arrangement 77.
FIG. 6 is a diagram of an alternative telephone handset 38' with
another wrist electrode arrangement. As shown in FIG. 6, rather
than plugging into handset 38', a pair of wrist bands 70A, 70B with
electrodes 72A, 72B may be coupled to telephone base station 36
via wires 76A, 76B and plug 79. In the example of FIG. 6, handset
38' carries RF telemetry wand 40, while telephone base station 36
carries wrist bands 70A, 70B. Accordingly, electronics for collecting
device information, such as device parameters and EGM information,
may be housed within handset 36, and electronics for collecting
surface ECG information may be housed in telephone base station
36.
FIG. 7 is a block diagram illustrating system 28 of FIG. 2 in greater
detail. As shown in FIG. 7, computer workstation 46 executes a software
application having an ECG monitor module 84, an EGM monitor module
86, and a parameter decoding module 88. ECG monitor module 84 manages
processing of surface ECG information received via transtelephonic
modulation (TTM) interface 48. In the example of FIG. 7, TTM interface
48 supports transtelephonic frequency modulation. EGM monitor module
86 manages processing of EGM information collected from IMD 10 and
received via modem 50. Parameter decoding module 88 manages processing
and storage of device parameter information collected from IMD 10
and received via modem 50.
In addition, remote monitoring station 30 includes a user interface
80 to receive user input and present information based on the device
information or surface ECG information, e.g., via a display device.
Also, remote monitoring station 30 includes a patient database 82
that organizes patient records containing patient test reports.
The patient test reports are generated by modules 84, 86, 88 and
contain both surface ECG information and device information, such
as device parameters of EGM information.
As further shown in FIG. 7, handset 38 includes an RF transmit/receive
(TX/RX) interface 90 to drive communication with IMD 10 via RF telemetry
wand 40. In addition, handset 38 includes ECG input interface 92
to receive surface ECG information obtained via ECG electrodes 44.
ECG input interface 92 includes amplifiers to amply the signals
received by ECG electrodes 44. Telephone base station 36 further
includes a parameter/EGM buffer 93 to store collected device information
prior to transmission of the information to remote monitoring station
30. A controller 94 directs memory transfers for transmission of
the device information, and controls a modem 96 to direct the transmission
via PSTN 34. In addition, controller 94 directs a transtelephonic
modulator (TTM) 98 to control real-time modulation and transmission
of surface ECG information to remote monitoring station 30 via telephone
interface 100 and PSN 34.
In operation, an operator associated with remote monitoring station
30 places a telephone call to patient 11. Patient 11 is instructed
to place ECG electrodes over his chest via handset 36 or on his
wrists via wrist bands 70A, 70B. The patient is also required to
place wand 40 for telemetry with IMD 10. During this procedure,
the operator may communicates with the patient 11 by voice via handset
38 or a speaker phone integrated with telephone base station 36.
The process of communicating with the patient during the implant
interrogation would allow obtaining a better quality records while
a patient is still on the phone. The improper placement of electrodes
and wand could be corrected while the patient is on the phone in
the process of monitoring the surface ECG. Additional commands that
are sent from the telephone or the keyboard of the remote monitoring
station 30 may allow resetting of the modem, instruct the patient
via a speaker or provide an alert signal advising the patient to
seek medical attention via a patient alert device.
FIG. 8 is a block diagram illustrating integrated patient monitoring
device 32 in greater detail. In the example of FIG. 8, patient monitoring
device 32 generally conforms to the device shown in FIG. 7. FIG.
8 further depicts, however, a touch tone decoder 106 that receives
a DTMF (dual tone multi frequency) signal when the operator of remote
monitoring station 30 presses a key on the touch-tone type telephone
52 (FIG. 2). Each key or sequence of keys corresponds to a command
for controller 94. FIG. 8 also shows a patient alert device 108
and a speaker 110.
In operation, RF TX/RX interface 90 receives device parameters
and EGM information from IMD 10. Controller 94 controls RF TX/RX
interface 90 and parameter/EGM buffer 93 to transfer the information
into the parameter/EGM buffer pending completion of transmission
of the surface ECG information. The surface ECG information flows
from ECG input interface 92 through TTM 98 and telephone interface
100 and across PSTN 34 to remote monitoring station 30.
RF TX/RX interface 90 also supplies time markers that are superimposed
on the ECG signal at the output of ECG input interface 92. Again,
the time markers indicate to an operator at remote monitoring station
30 that the device information, i.e., parameters and EGM information,
are being collected as transmission of the surface ECG information
continues. When a sufficient amount of surface ECG information has
been transferred to remote monitoring station 30, controller 94
controls ECG input interface 92 to stop transmission of the surface
ECG information. After the transtelephonic transmission of surface
ECG information is stopped, controller 94 controls parameter/EGM
buffer 93 to transfer its contents to modem 96 for transmission
to remote monitoring station 30 via PSTN 34.
The operator at remote monitoring station 30 issues commands to
patient monitoring device 32 via transtelephonic transmission. The
commands may be received by patient monitoring device 32 while transtelephonic
transmission of the surface ECG information is taking place. Touch
tone decoder 106 receives a variety of commands from remote monitoring
station 30, which enable the remote monitoring station to control
collection of information by patient monitoring device 32.
The commands transmitted by remote monitoring station 30 may include:
Real Time EGM On/Off, Stored parameters and Stored EGM On/Off, Memory
transfer On/Off, TTM transfer On/Off, Speaker On/Off, Patient Alert
On/Off, and System Reset. The Real Time ECG On/Off command causes
controller 94 to stop or start collection of surface ECG information.
The Real Time EGM On/Off command causes controller 94 to start or
stop collection of device EGM information from IMD 10.
The Memory transfer On/Off command causes controller 94 to start
or stop transfer of device information to and from Parameter/EGM
buffer 93. The TTM transfer On/Off command causes controller 94
to stop or start transtelephonic transmission. The Speaker On/Off
command causes controller 94 to turn speaker 110 on or off. The
Patient Alert On/Off command causes controller 94 to turn speaker
108 on or off. The System Reset command causes controller 94 to
reset patient monitoring device 32.
In operation, the operator of remote monitoring station 30 speaks
on the telephone with patient 11, and instructs the patient to place
handset 38 proximate the implant area on the patient's chest. As
soon as the patient palaces electrodes properly on the chest, the
surface ECG can be transferred to remote monitoring station 30.
The operator observes the surface ECG information, which may be
a waveform, on a display device. The surface ECG waveform may include
regular spikes every few seconds, which represent the time markers
generated by RF TX/RX interface 90.
The time markers indicate that RF telemetry wand 40 is properly
placed relative to IMD 10 and that RF transmission is taking place.
A touch tone command sent by the operator will start collection
of device parameters and EGM information. When the operator determines
that a sufficient, artifact free sample of the surface ECG is collected
in the presence of the EGM, the operator sends another command to
transfer the stored implant parameters and stored EGM records from
patient monitoring device 32 to remote monitoring station 30 via
PSTN 34.
FIG. 9 is a chart illustrating collection of device information
and surface ECG information. As shown in FIG. 9, patient monitoring
device 32 transmits a real-time surface ECG information in the form
of an ECG waveform 113. ECG waveform 113 is preceded by a synchronization
marker 115 and followed by a synchronization marker 117. While the
real-time surface ECG information is being transmitted, patient
monitoring device 32 also obtains real-time EGM information from
IMD 10 via RF telemetry, as indicated by reference numeral 119.
Then, patient monitoring device 32 obtains stored parameters and
stored EGM information from IMD 10, as indicated by reference numeral
121. Transmission of the surface ECG information from patient monitoring
device 32 to remote monitoring device 30 can be referred to as real-time.
Transmission of real-time and stored device information from IMD
10 to patient monitoring device 32 can be referred to as import
time. Transmission of the real-time and stored device information
from patient monitoring device 32 to remote monitoring device 30
can be referred to as export time.
Patient monitoring device 32 generates time markers 123 and superimposes
the time markers on the TTM channel transmitted to remote monitoring
station 30. The time markers 123 on the TTM channel indicate that
the telemetry process is taking place between patient monitoring
device 32 and IMD 10. Once the time markers stop appearing on the
transtelephonic transmission of ECG information, the operator at
remote monitoring station 30 determines that the telemetry is over,
and that the device information has been successfully transferred
to patient monitoring device 32.
A synchronization marker 125 is placed at the end of the time markers
123. The operator then contacts patient 11, terminates the voice
transmission, and starts transmission of digital data via modem
96 to transfer the device information, as indicated by reference
number 127 The device information may include the real time EGM
119 and stored device parameters and stored EGM information 121
accumulated during the telemetry process.
Remote monitoring station 30 transmits the real-time EGM On command
to activate the telemetry between IMD 10 and patient monitoring
device 32 for real-time EGM transmission. At the same time, the
real-time EGM On command indicates to RF TX/RX interface 90 that,
at the start of the real time telemetry of the EGM data, the synchronization
marker signal must be sent to ECG input interface 92 to indicate
the starting time of EGM recording. This first synchronization marker
will allow synchronizing the real time surface ECG recording with
the EGM recording transmitted by RF TX/RX interface 90. The final
synchronization can be done by remote monitoring station 30. The
purpose for such synchronization is to be able to display surface
ECG and device EGM in the same time domain for clinical evaluation.
When the operator is satisfied that an acceptable sample of surface
ECG has been obtained, along with a steady stream of time marker
pulses, the operator issues a Stored parameters and Stored EGM On
command. This command stops the real time EGM telemetry. This command
also indicate to RF TX/RX interface 90 to send another synchronization
pulse that will indicate the start of transfer of stored device
parameters and stored EGM information. A stream of Time Markers
will continue appearing on the TTM channel during importation of
the stored parameters and stored EGM information from IMD 10 to
patient monitoring device 32. These time markers will appear on
the TTM channel for as long as the parameters and stored EGM information
take to transfer. When the transfer of parameters and stored EGM
information stops, the time markers stop appearing on the TTM channel.
At this point, remote monitoring station 30 issues the Memory transfer
On/Off command to cause patient monitoring device 32 to transmit
the real time EGM, stored parameters and stored EGM information.
FIG. 10 is a block diagram illustrating operation of a remote monitoring
station 30 in greater detail. As shown in FIG. 10, remote monitoring
station 30 receives touch-tone control input 111 for communication
to patient monitoring device 32 via TTM interface 48. The signals
into transtelephonic interface 48 and modem interface 50 are received
from PSTN 34. Transtelephonic demodulation software 112 converts
the signal into digital format and places it in surface ECG digital
buffer 118 while the modem software 114 fills real time EGM buffer
130, stored EGM buffer 134 and stored parameter buffer 142. Modem
software 114 identifies real time EGM information, stored EGM information,
and stored device parameters, as discussed above with reference
to the diagram of FIG. 9, and the information encoded into the structure
of digital data obtained from modem interface 50.
Surface ECG display software 120 and real-time EGM display software
132 are adjusted in accordance with the synchronization markers
transmitted on the TTM channel by ECG-EGM display synchronization
software 122. Stored parameter decoding software 144 decodes parameter
information to a form suitable of presentation by stored parameter
display software 146. The second synchronization marker represents
the end of the real time EGM recording. The time markers on TTM
transmissions will indicate that telemetry between IMD 10 and patient
monitoring device 32 is taking place.
When the operator realizes that there are no further time markers,
the operator sends a command to start transfer of the contents of
the parameter/EGM buffer 93. Upon the end of the transmission, a
modem interface software end of digital transmission signal 116
is sent to buffers 130, 134, 142 to initiate software 120, 132,
144, 146 for displaying surface ECG, real time EGM and stored parameters.
The synchronization maker permits the operator to verify and, if
necessary, adjust the relative position of the surface ECG and the
real time EGM on a display device. The operator will have the opportunity
to review the stored EGM as well as stored device parameters in
conjunction with the real-time EGM and surface ECG information.
Remote monitoring station 30 then stores the pertinent information,
e.g., via ECG-EGM storage software 124, stored EGM storage software
138, and parameter storage software 148. The stored information
can be stored in a database in a patient record 128, as prepared
by patient database ECG-EGM record software 126, patient database
EGM record software 140, patient database parameter software 150.
Upon storing the result of test the system operator can generate
reports that summarize patient test results.
FIG. 11 is a flow diagram illustrating a process for remote monitoring
of implanted medical devices and surface ECG information. As shown
in FIG. 11, the process involves initiating a telephone call (164),
collecting device information (166) from IMD 10 and buffering the
device information (168). The process also involves collecting surface
ECG information (170), and transmitting the surface ECG information
from patient monitoring device 32 to remote monitoring station 30
using a TTM interface (172). When the surface ECG transmission is
complete (174), the process further involves transmitting the buffered
device information from patient monitoring device 32 to remote monitoring
station 30 using a modem (176). Once the transmission of device
information is complete (178), the telephone call is terminated
(180).
FIG. 12 is a flow diagram illustrating additional details of the
process of FIG. 9. As shown in FIG. 12, upon initiation of a telephone
call (182), instructions are received from remote monitoring station
30 (184). Patient monitoring device 32 presents the instructions
to patient 11 (186), e.g., visually or audibly. The instructions
may include instructions for proper positioning of electrodes, an
RF telemetry wand, or both. Upon verification of proper RF wand
and electrode positioning (188), patient monitoring device 32 receives
a control signal from remote monitoring station 30 to commence collection
of information (190). Then, remote monitoring station 30 receives
a control signal to transmit the collected information (192), and
responds by transmitting the information (194). The transmission
of the information may be in an order and format as described above
with reference to the diagram of FIG. 9.
Some of the techniques described herein may be embodied as a computer-readable
medium comprising instructions for a programmable processor. The
programmable processor may include one or more individual processors,
which may act independently or in concert. A "computer-readable
medium" includes but is not limited to read-only memory, Flash
memory and a magnetic or optical storage medium.
Various embodiments of the invention have been described. However,
one skilled in the art will appreciate that various modifications
may be made to these embodiments without departing from the scope
of the invention. These and other embodiments are within the scope
of the following claims. These and other embodiments are within
the scope of the following claims.
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