U.S. patent number 3,724,455 [Application Number 05/042,850] was granted by the patent office on 1973-04-03 for cardiac warning device.
Invention is credited to Paul N. Unger.
United States Patent |
3,724,455 |
Unger |
April 3, 1973 |
CARDIAC WARNING DEVICE
Abstract
A method and apparatus for detecting and responding to herald
signs in the cardiac waveform, such as a fast heartbeat rate, a low
rate or a skipped heartbeat. In one embodiment the detection of a
herald sign causes the ECG waveform to be transmitted to a remote
location where it is analyzed and a signal retransmitted to the
patient triggering an alarm or causing other appropriate action. In
another embodiment, the detection of a herald sign causes the ECG
to be recorded on a loop of magnetic tape or a modular solid state
memory device in the unit so that the tape can be replayed and
acoustically coupled to the telephone line after the patient calls
the central facility. In yet another embodiment, the detection of
different herald signs causes different alarm signals, e.g.,
colored lights, different alarm signals identifying the
abnormality, to be operated to indicate to the patient what
medication he should administer to himself or whatever other action
he should take in the event that communication with central
facility cannot be immediately achieved.
Inventors: |
Unger; Paul N. (Miami Beach,
FL) |
Family
ID: |
21924076 |
Appl.
No.: |
05/042,850 |
Filed: |
June 2, 1970 |
Current U.S.
Class: |
600/515; 128/905;
128/903; 607/5; 600/519 |
Current CPC
Class: |
A61B
5/0006 (20130101); Y10S 128/905 (20130101); Y10S
128/903 (20130101) |
Current International
Class: |
A61B
5/00 (20060101); A61b 005/04 () |
Field of
Search: |
;128/2.5R,2.5S,2.5T,2.6A,2.6F,2.6G,2.6R,2.1A,2.1R,419D |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kamm; William E.
Claims
What is claimed is:
1. An apparatus for detecting potentially dangerous herald signs in
a cardiac waveform of an individual comprising:
means for detecting the cardiac waveform and producing a signal
representing that waveform,
means for receiving said representing signal, producing a first
output signal when the heartbeat rate is less than a first given
rate and producing a second output signal when the heartbeat rate
is greater than a second given rate,
means for receiving said first output signal and producing a light
of a first color to the individual that the rate has been
determined to be less than said first rate,
means for receiving said second output signal and producing a light
of a second color different from said first warning signal and
indicating to the individual that the rate has been determined to
be greater than said second rate,
means for receiving said representing signal, said first output
signal and said second output signal and for recording said
representing waveform for a given time after receipt of either said
first output or second output signal,
means for transmitting the recorded signal, to a remote facility
after said herald sign is detected, and
means for receiving said first output signal and said second output
signal and producing an audible noise whenever either said first
color light or said second color light is produced.
2. An apparatus as in claim 1 including means for manually
adjusting the volume of said third warning signal.
3. An apparatus as in claim 1 wherein said transmitting means
includes means for detachably coupling said transmitting means to a
telephone line.
4. An apparatus as in claim 1 wherein said receiving and first and
second output signal means includes means for producing a third
output signal when a heartbeat is skipped and including means for
receiving said third output signal and producing a third warning
signal indicating to the individual that the heartbeat has been
skipped.
5. An apparatus as in claim 1 including a housing containing all of
said means and adapted to be carried by said individual.
6. An apparatus for detecting and responding to herald signs in the
cardiac waveform of an individual comprising:
means for detecting the cardiac waveform and producing a signal
representing that waveform,
means for receiving and recording said representing signal, and
means for receiving said representing signal for detecting herald
signs and for controlling said receiving and recording means so
that said receiving and recording means preserves a portion of said
representing signal whenever a herald sign is detected,
including
means for translating said recorded representing signal into a
radio signal and transmitting said radio signal to a remote
facility,
means for receiving a radio signal from said remote facility and
producing an alarm signal which is manifest to said individual.
7. An apparatus as in claim 6 wherein said receiving and producing
means includes defibrillating means operable in response to a given
signal from said remote receiver.
8. A system for detecting and responding to herald signs in the
cardiac waveforms of individuals comprising:
a central monitoring facility including computer means for
receiving and analyzing a received signal, means for displaying the
output of said computer means, memory means for storing the output
of the computer and means for transmitting the output of the
computer to a remote location, and
a plurality of individual units each adapted to be carried with an
individual and each including,
means for detecting the cardiac waveform and producing a signal
representing that waveform,
means for detecting a herald sign,
means for receiving and recording said representing signal for a
given time after a herald sign is detected, and
means for transmitting said recording to said central facility.
9. A method of detecting and responding to herald signs in the
cardiac waveforms of individuals in a system with a central
monitoring facility and a plurality of individual units each
adapted to be carried with an individual comprising the steps
of:
detecting the cardiac waveform in each individual unit and
producing a signal representing that waveform,
detecting a herald sign in each unit,
recording and retaining said representing signal in a unit for a
given time after a herald sign is detected in that unit, and
transmitting said recording to said central facility after a herald
sign is detected, analyzing said transmitted recording in said
central facility and transmitting information with respect to
future actions to be taken from said central facility back to the
individual having a unit which has transmitted said recording after
detecting a herald sign.
10. A method of detecting and responding to herald signs in the
cardiac waveforms of individuals in a system with a central
monitoring facility and a plurality of individual units each
adapted to be carried with an individual comprising the steps
of:
detecting the cardiac waveform in each individual unit and
producing a signal representing that waveform,
detecting a herald sign in each unit,
recording and retaining said representing signal in a unit for a
given time after a herald sign is detected in that unit, and
transmitting said recording to said central facility after a herald
sign is detected, receiving and analyzing the transmitted signal in
computer means at said central facility, displaying the output of
said computer means, storing the computer output and transmitting
the computer output to a remote location.
Description
BRIEF DESCRIPTION OF THE PRIOR ART AND SUMMARY OF THE INVENTION
This invention is described in Document Disclosure Number 001756
filed Apr. 11, 1970.
The invention relates to a method and apparatus for detecting
premonitory signs of cardiac attacks and transmitting the detecting
signs to a central location.
Almost all, if not all serious or potentially serious cardiac
attacks are prefaced by warning or patient unrecognizable herald
signs in the ECG wave which occur in many patients long before
recognizable symptoms become manifest. A number of such signs have
been discovered and these include reduction in the heart rate below
a low selected rate limit, e.g., 54 and an increase above a high
selected limited rate, e.g., 120-130, premature heart beats,
failure to discharge an impulse, failure of an electrical impulse
to be conducted from the upper to the lower chambers, widening of
the QRS complex, base line shift depression or elevation, and
abrupt ST deviation.
While all of these signs do not always indicate a cardiac attack is
imminent, their occurrence, particularly in individuals with
previous cardiac difficulties or established potential cardiacs, is
serious enough to warrant careful study by an expert and, following
recognition, institution of precautionary measures, such as
indicated treatment with drugs. For some signs, for example, when
the rate slows below about 50, action should be taken immediately.
However, inasmuch as many of the signs do not normally cause
distress or perceptible physical symptoms, they may pass unnoticed
or even if noticed their import may not be fully appreciated or may
be rationalized away.
The present invention relates to a novel method and apparatus
whereby a number of individuals known to be cardiacs or potential
cardiacs are each equipped with a portable unit which they carry on
or with their person and which constantly monitors the ECG wave for
herald signs.
In one embodiment of this invention, the detection of a herald sign
by the unit causes the ECG to be transmitted to a central facility
where it triggers a programmed signal in a central computer in
addition to that generated in the unit. The ECG wave received at
the central facility is then analyzed, preferably by a digital,
single purpose computer which then generates an output based on a
programmed input which a human expert can then study, preferably
after transmission by magnetic tape via dataphone or similar device
onto a receiving screen or other ECG display. If the expert
considers that the detected signs warrant precautionary measures,
he after identifying by coded number the patient and physician,
directs the activation of a transmitter which sends a signal to the
unit transmitting the ECG waves, triggering an audio signal to the
patient. He simultaneously communicates with the patient's
physician, advising him of the event of the identified patient.
This maintains the patient-personal physician relationship without
interposing the interpreter as a patient identifiable consultant,
but retaining his identity as a physician consultant.
This alarm within the patient unit indicates to the individual that
he should contact his own physician immediately for instructions,
or, if that proves impossible, the central facility. At the same
time that the expert directed activation of the alarm transmitter,
he also alerted the personal physician to the situation. He can
also transmit to the personal physician, via a telephone
transmitter or similar device, the actual ECG which the computer
has processed and presented to him. The alarm signal may also
indicate to the patient what self medication should be
administered, e.g., by the color of a light lit by the signal as a
fail safe device in the event of any breakdown in communication
such as inability to reach computer monitor facility and/or his
physician. The detection of a herald sign by the unit may also
cause the alarm to be activated if desired.
One of the advantages of this arrangement is that the logic in each
personal unit need not make sophisticated decisions as to whether a
detected sign warrants precautions; those decisions are made by the
computer and ultimately evaluated by a human expert. Accordingly,
the logic in each unit can be made fairly simple, responding only
to a few simple conditions which always occur when a herald sign
exists. This permits the unit to be made relatively inexpensively
and small enough to be easily carried by the patient. Another
advantage is that the patient is not bothered by periodic false
alarms which breed anxiety and cause loss of sleep. The patient's
alarm operates only when a potentially serious consideration exists
which warrants further study and which he has been taught is an
early warning signal which may warrant preventive protective
actions.
In another embodiment of the invention each unit includes an
endless loop of magnetic tape or a solid state memory device on
which the ECG wave can be continuously recorded and when the logic
network in the unit determines that a herald sign is occurring
permits playback and prevents erasure. Alternately the ECG waveform
is recorded on the tape where it is used only after the event has
occurred. Alternately, a solid state memory device permits
continuous recording with modularity in choice of playback time
with 10 seconds deemed adequate to meet the overwhelming majority
of events and 30 seconds virtually all events. It has been found
that the waveform after the event almost always indicates the
herald sign which caused the alarm to be given.
The logic also triggers an audio alarm in the unit which indicates
to the individual that he should go to the nearest telephone and
call the central facility. One or more visual signals can be also
given by different colored signals to inform the individual as to
which medicine should be self-administered where particular hazard
exists and communication cannot be immediately established. When
the telephone connection has been made, the magnetic tape or solid
state memory device is played back while linked to the telephone by
a conventional or miniaturized acoustic coupler and the recorded
ECG thus transmitted to the central facility. The received signals
are then processed by a single purpose properly programmed computer
simultaneously displayed on a screen and continuously recorded on
tape and transmitted to a human expert who then studies the output
and determines what actions should be taken. Instructions can then
be immediately given to the individual's physician or in his
absence, to the individual, over the telephone.
In a third embodiment of the invention, the detection of a herald
sign causes one of a plurality of colored lights or similar
indicators to light, thus indicating to the patient what
self-medication he should administer to himself or whatever other
steps he should take in the inability to immediately communicate
with the center and his physician, or whenever immediate danger
exists. Particularly, the detection of a heartbeat rate below a
given value, detection of a heartbeat rate above a given value or
detection of a skipped heartbeat are three herald signs which can
cause different lights to be lit, in addition to the operation of
an audio alarm.
Many other objects and purposes of the invention will become clear
from the following detailed description of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a first embodiment of this invention, whereby the ECG
waveform of an individual wearing the unit is transmitted to a
central facility continuously, etc. when the unit detects a herald
sign.
FIG. 2 shows a second embodiment of this invention.
FIG. 3 shows a normal ECG waveform.
FIG. 4 shows a third embodiment of this invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Reference is now made to FIG. 1 which shows a first embodiment of
this invention. In this embodiment, a number of individuals with
established cardiac difficulties or who are cardiac prone are each
equipped with a portable, self contained and powered unit which
monitors their ECG waveforms continuously and responds to
conditions which appear to be herald signs. In FIG. 1, three such
units 20, 22 and 24 are diagrammatically illustrated.
As shown, unit 24, which is intended to be identical to units 20
and 22, includes a power source 26 which may be a small
nickel-cadmium or other battery and which supplies the energy
requirements of unit 24. If desired, provision may be made for
visually or audibly indicating to the wearer when the battery is
marginally depleted or the electrical system is malfunctioning.
A conventional amplifier 28 of which many types are known detects
the minute electrical signals produced by the electrodes connected
to the body and amplifies them to produce the conventional ECG
waveform. A normal ECG wave is shown in FIG. 3. The ECG waveform
signal produced by amplifier 28 is passed to logic network 30 which
then determines, by built-in programming, if a condition exists
which might be a herald sign. For example, logic 30 may include a
timing circuit which checks the temporal separation between each R
wave peak and the last R wave peak and produces an alarm signal if
the separation is less than a first given time or greater than a
second given time, thus detecting high and slow heartbeat rates as
well as skipped beats. As discussed below, unit 24 preferably
includes a recorder 31.
Whenever logic 30 detects a herald sign, it produces a trigger
signal which is passed to transmitter 32 which causes transmitter
32 to transmit, at an assigned frequency, the ECG waveform signal
being produced by amplifier 28. The ECG information may be
modulated onto the transmission frequency or otherwise sent. While
microwave or low RF signals may be satisfactory in regions where
there are few large steel structures VHF signals are believed to be
more satisfactory under all conditions based on present technology.
Each of the units in the system will preferably be assigned a
different frequency so that the source of received signals can be
quickly and reliably ascertained. The use of six digits to each
multihertz cycle with multiplexing permits the simultaneous
transmission of large numbers of ECG signals from different
individuals only at such times when a herald sign is detected.
The central facility 34 receives the signals transmitted by unit 24
and, more particularly, a receiver 36 detects the transmitted
signals and converts them to a frequency or form, such as AC
current, suitable for use by the digital computer 38 which is
properly programmed to analyze the ECG waveform and provide
information as an output, including the ECG waveform, useful to the
expert, who is continuously on alert when signalled.
Computer 38 analyzes the information received and, when warranted,
triggers an output alarm 40 and provides an output on monitor or
print-out 42 for the human expert to study. The monitor may be an
oscilloscopic monitor and/or print-out and the information provided
preferably includes the ECG waveforms received, the patient's
identification and the identification of the patient's personal
physician.
The computer 38 also preferably permanently records the received
ECG waveform on tape storage 45 which may be destroyed from time to
time. If desired, computer 38 may at the same time transmit the ECG
to another remote monitor 39 such as the office or bedside of the
personal physician and/or cardiac consultant of the person
transmitting the ECG waveforms.
The human expert studies the ECG on monitor 42 and/or monitor 39
and if he considers that the situation warrants precautions, he
directs manual activation of transmitter 44 after it is
automatically set to the frequency of the unit to be contacted by
computer 38. The signals transmitted for example by transmitter 44
are received by receiver 46 which includes a filter tuned to the
frequency assigned to unit 24. If the signal as produced or passed
by receiver 46 is at the assigned frequency, a signal is produced
or passed by receiver 46 which triggers alarm 48 which includes an
audio alarm and which tells the person wearing unit 24 that he
should contact his personal physician or, if he is unavailable,
center 34 immediately. The transmitted signal received by receiver
46 can also be used to trigger other devices in unit 24. For
example, in FIG. 1 a defibrillator is provided which can be
triggered by facility 34 upon detection of ventricular
fibrillation. Different colored lights indicating varying causes
and hence different courses of action can also be lit as discussed
below. The human expert preferably alerts the personal physician
before or just after transmitter 44 is activated.
One of the drawbacks of the above discussed embodiment is the
difficulty in transmitting through all environments in which the
wearer may find himself including large buildings of steel and
concrete. Even at VHF frequencies transmission may be impaired or
distorted with possible failure of the center to detect or receive
herald signs, but at frequencies between roughly 2-50 MHz this
problem is believed minimized.
In a second embodiment of the invention shown in FIG. 2 this
problem is eliminated by providing a continuous tape loop 50 or a
solid state memory device in the portable unit which is triggered
by logic 52 when the logic determines that a condition which is a
herald sign exists. As in the embodiment of FIG. 1, a conventional
power supply 54 and ECG detector 56 are provided.
When triggered, an erasable tape loop 50 or solid state memory
device or other recorder, records the ECG waveform for some given
time, e.g., until the entire loop has been filled. If desired, tape
loop 50 can record continuously and stop erasing only when a herald
sign is detected. However, it has been determined that the ECG
signal after the event occurs almost always indicates the nature of
the problem and the event. Accordingly, the greater simplicity in
design and less power consumption of this approach suggests that
recording will usually be desirable only upon detection of a herald
sign. Logic 52 also responds to the detection of a condition which
might be a herald sign by operating an audio alarm 55 which alerts
the patient, who has been instructed to go immediately to a
telephone and call the central facility which as in FIG. 1 is
equipped with a computer and accessibility to a human expert for
analyzing the recorded ECG waveform. Alarm 55 can also include
lights or other indicators which further tell the patient what
actions should be taken. If desired, the patient can be
continuously coupled to the phone and his ECG continuously
monitored by the computer.
When the center has been reached, the tape is played and the
information passed to the center via acoustic coupler 60 which is
operated by manual control 62 and the telephone lines. The computer
at the central facility then receives the information and produces
an output as in FIG. 1 for the human expert to study. After the ECG
has been completely transmitted, the unit wearer receives detailed
instructions from the human expert as to what he should do.
Reference is now made to FIG. 4 which shows a further embodiment of
the invention of this application. In this embodiment, the ECG
waveform is detected by properly placed electrodes and an amplified
signal from amplifier 70 is applied to logic 72 which, like the
other logic devices described above, detects one or more herald
signs. In particular, logic 72 is designed to detect when the
heartbeat rate is less than a given value, for example, about 54
beats per minute, greater than a second value, for example, 120-130
beats per minute, or when a heartbeat has been skipped. Many simple
logic arrangements for detecting these conditions should be
apparent and these include arrangements for determining the time
between adjacent R-wave peaks and for triggering appropriate
signals on different outputs when that spacing is greater than, or
less than, preset values. A conventional power supply 74, which may
also be of the type described above, supplies the power to logic 72
as well as the other elements of the device.
Whenever a herald condition is detected an appropriate signal is
produced on line 76 which triggers an audio alarm 78 which the
patient can hear. A manual volume adjustment 80 is provided so that
the volume can be increased during sleep, or when the patient is
under conditions where the audio alarm 78 might not otherwise be
heard.
Further, logic 72 is provided with three or more additional outputs
each of which are connected to a separate indicator which is in
this embodiment a colored light. Thus when a low heartbeat rate is
detected, a signal is produced on line 82 which causes line 84 to
become illuminated and remain illuminated. Similarly, the detection
of a high heartbeat rate causes an appropriate signal to be
produced on line 86 to cause illumination of colored light 88.
Further, the detection of a skipped heartbeat produces a signal on
line 90 which causes light 92 to be lit. Each of the lights 84, 88
and 92 are preferably of different colors, for example, red, yellow
and green.
Thus, the patient is not only warned that a herald sign has
occurred, he is specifically informed as to the condition which
caused the audio alarm 78 to operate. This is important since there
are many circumstances under which it is necessary for the patient
to respond to the detected condition. A low heart rate is
particularly critical since competing lower and mechanically
inadequate rhythmic centers may escape with resultant cardiac
arrest and/or shock. The detection of a skipped beat may also be
important enough to justify some immediate action. High heartbeat
rates except ventricular tachycardia do not normally require
immediate action unles ventricular fibrillation results, in which
case the patient will be unable to respond to the warning
himself.
Accordingly, it is contemplated that with this embodiment, the
patient will be provided with appropriate drugs to use when the
associated light goes on, when immediate communication with the
physician is impossible. The drugs may be taken in any form. While
the critical point for the low rate is fairly constant, the point
at which logic 72 should trigger a warning for a high heartbeat
rate may vary from individual to individual and according to the
activities of that individual. Accordingly, it is desirable to be
able to adjust the rate value which triggers logic 72 and a
suitable mechanism 100 for accomplishing that purpose is shown in
FIG. 4. Normally, this adjustment will be unavailable to the
patient but will be made by the physician at the time that the
individual is given the unit or subsequently when indicated.
While the patient can administer medicine to himself in response to
the various alarm signals, it is contemplated that he will be
instructed to contact his physician or someone else whenever he
receives an alarm. Further, it is contemplated that this type of
unit can be used in combination with the transmitter unit or the
recording device shown in FIGS. 1 and 2, and that logic 72 will be
designed so as to be compatible with such other devices. The unit
shown in FIG. 4 may then be used initially with those patients who
are not thought to be extremely serious. If later the patient's
condition warrants it, the appropriate recording mechanism and
acoustical coupler or transmitter can be added.
Many changes and modifications in the above embodiment of the
invention can, of course, be made without departing from the scope
of the invention and that scope is intended to be limited only by
the scope of the appended claims.
* * * * *