U.S. patent application number 11/493555 was filed with the patent office on 2007-02-01 for system for patient alerting associated with a cardiac event.
Invention is credited to Mary Carol Day, David R. Fischell, Jonathan Harwood.
Application Number | 20070027397 11/493555 |
Document ID | / |
Family ID | 34795399 |
Filed Date | 2007-02-01 |
United States Patent
Application |
20070027397 |
Kind Code |
A1 |
Fischell; David R. ; et
al. |
February 1, 2007 |
System for patient alerting associated with a cardiac event
Abstract
A system for the detection of cardiac events occurring in a
human patient is provided. At least two electrodes are included in
the system for obtaining an electrical signal from a patient's
heart. An electrical signal processor is electrically coupled to
the electrodes for processing the electrical signal and a patient
alarm means is further provided and electrically coupled to the
electrical signal processor. The patient alarm means generates an
escalating sensory alarm signal over a predetermined time period
subsequent to the electrical signal processor if the processor
detects a cardiac event. The patient alarm means may be further
applied to a pacemaker or defibrillator system.
Inventors: |
Fischell; David R.; (Fair
Haven, NJ) ; Harwood; Jonathan; (Rumson, NJ) ;
Day; Mary Carol; (Middletown, NJ) |
Correspondence
Address: |
ROSENBERG, KLEIN & LEE
3458 ELLICOTT CENTER DRIVE-SUITE 101
ELLICOTT CITY
MD
21043
US
|
Family ID: |
34795399 |
Appl. No.: |
11/493555 |
Filed: |
July 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10765040 |
Jan 28, 2004 |
7107096 |
|
|
11493555 |
Jul 27, 2006 |
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Current U.S.
Class: |
600/516 ;
607/25 |
Current CPC
Class: |
A61B 5/349 20210101;
A61B 5/363 20210101; A61B 5/076 20130101; A61B 5/686 20130101; A61B
5/0031 20130101; A61B 5/1112 20130101 |
Class at
Publication: |
600/516 ;
607/025 |
International
Class: |
A61B 5/04 20060101
A61B005/04 |
Claims
1-40. (canceled)
41. An implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient comprising:
(a) a pacemaker adapted for insertion into the human patient; (b) a
pacemaker lead coupled to the pacemaker for obtaining an
electrogram electrical signal from the patient's heart; (c) an
electrical signal processor coupled to the pacemaker lead for
processing the electrogram electrical signal and detecting a
cardiac event; and, (d) patient alarm means coupled to the
electrical signal processor for generating an escalating sensory
alarm signal received by the patient over a predetermined time
period subsequent to the electrical signal processor detecting the
cardiac event.
42. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the cardiac event is coronary ischemia indicated
by a change in the ST segment of the electrogram.
43. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the cardiac event is coronary ischemia indicated
by a change in the ST segment of the electrogram at an elevated
heart rate.
44. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the cardiac event is an arrhythmia.
45. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 44 wherein the arrhythmia is high heart rate.
46. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 44 wherein the arrhythmia is low heart rate.
47. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 44 wherein the arrhythmia is an unsteady heart rate.
48. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 47 wherein the unsteady heart rate is the result of PVCs.
49. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 47 wherein the unsteady heart rate is the result of atrial
fibrillation.
50. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the escalating alarm signal progressively
increases in amplitude over time.
51. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 50 wherein the escalating alarm signal increases in amplitude
over time only for a preset time period.
52. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 50 wherein the escalating alarm signal includes a
multiplicity of successive alerting signals spaced in time by a
time interval, the successive alerting signals increasing in
amplitude over time.
53. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the escalating alarm signal includes a
multiplicity of successive sets of alerting signals, each set
including two or more alerting signals the alerting signals within
each set spaced apart in time by an intra-set time interval.
54. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 43 wherein the escalating alarm signal is produced by a
decreasing intra-set time interval in successive sets of alerting
signals.
55. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 43 wherein the sets of two or more alerting signals are
spaced apart in time by an inter-set time interval.
56. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 55 wherein the inter-set time interval is longer than the
intra-set time interval.
57. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 55 wherein the inter-set time interval is greater than one
second.
58. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 55 wherein the intra-set time interval is less than 1
second.
59. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the escalating alarm signal includes a
multiplicity of successive sets of alerting signals, the sets
spaced apart in time by an inter-set time interval.
60. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 59 wherein the escalating alarm signal is produced by a
progressively decreasing inter-set time interval between successive
sets of alerting signals.
61. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the escalating alarm signal includes a
multiplicity of successive sets of alerting signals, each set
including one or more alerting signals, the number of alerting
signals in each set increasing over time.
62. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 61 wherein the time interval between alerting signals in sets
of alerting signals including 2 or more alerting signals
progressively decreases over time.
63. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the escalating alarm signal includes a
multiplicity of alerting signals, the alerting signals increasing
in duration over time.
64. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the escalating alarm signal includes a
multiplicity of alerting signals, the alerting signals
progressively increasing in frequency over time.
65. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the escalating alarm signal includes an internal
alarm signal originating from an implanted medical device.
66. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 65 wherein the internal alarm signal is includes a
vibration.
67. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 65 wherein the internal alarm signal includes an electrical
tickle.
68. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 65 wherein the internal alarm signal includes a sound.
69. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 65 further including an escalating external alarm signal.
70. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 65 further including an external alarm signal generated by an
external alarm system is of constant level of perceptibility to the
patient.
71. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 65 further including an external alarm signal generated by an
external alarm system, the external alarm signal being initiated at
a preset time before the initiation of the escalating internal
alarm signal.
72. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 71 wherein the external alarm is an escalating alarm
signal.
73. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 65 further including an external alarm signal generated by an
external alarm system, the external alarm signal being initiated at
a preset time after the initiation of the escalating internal alarm
signal.
74. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 73 wherein the external alarm signal is an escalating alarm
signal.
75. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 41 wherein the escalating alarm signal includes an external
alarm signal originating from an external alarm system.
76. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 76 wherein the internal alarm signal includes a
vibration.
77. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 76 wherein the internal alarm signal includes a visual
display.
78. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 76 wherein the internal alarm signal includes a sound.
79. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 76 further including an internal alarm signal generated by an
implanted medical device, the internal alarm signal being of
constant level of perceptibility to the patient.
80. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 79 wherein the escalating external alarm signal is initiated
at a preset time before the initiation of the constant internal
alarm signal.
81. An implantable cardiac defibrillator having capability of
detecting cardiac events occurring in a human patient comprising:
(a) a defibrillator adapted for insertion into the human patient;
(b) at least one lead coupled to the defibrillator for obtaining an
electrogram electrical signal from the patient's heart; (c) an
electrical signal processor electrically coupled to said electrode
for processing the electrogram electrical system and detecting a
cardiac event; and, (d) patient alarm means coupled to the
electrical signal processor for generating an escalating sensor
alarm signal received by the patient over a predetermined time
period subsequent to the electrical signal processor detecting the
cardiac event.
82. The implantable cardiac defibrillator system having capability
of detecting cardiac events occurring in a human patient as recited
in claim 81 wherein the cardiac event is coronary ischemia
indicated by a change in the ST segment of the electrogram.
83. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the cardiac event is coronary ischemia indicated
by a change in the ST segment of the electrogram at an elevated
heart rate.
84. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the cardiac event is an arrhythmia.
85. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 84 wherein the arrhythmia is high heart rate.
86. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 84 wherein the arrhythmia is low heart rate.
87. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 84 wherein the arrhythmia is an unsteady heart rate.
88. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 87 wherein the unsteady heart rate is the result of PVCs.
89. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 87 wherein the unsteady heart rate is the result of atrial
fibrillation.
90. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the escalating alarm signal progressively
increases in amplitude over time.
91. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 90 wherein the escalating alarm signal increases in amplitude
over time only for a preset time period.
92. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 90 wherein the escalating alarm signal includes a
multiplicity of successive alerting signals spaced in time by a
time interval, the successive alerting signals increasing in
amplitude over time.
93. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the escalating alarm signal includes a
multiplicity of successive sets of alerting signals, each set
including two or more alerting signals the alerting signals within
each set spaced apart in time by an intra-set time interval.
94. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 93 wherein the escalating alarm signal is produced by a
decreasing intra-set time interval in successive sets of alerting
signals.
95. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 93 wherein the sets of two or more alerting signals are
spaced apart in time by an inter-set time interval.
96. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 95 wherein the inter-set time interval is longer than the
intra-set time interval.
97. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 95 wherein the inter-set time interval is greater than one
second.
98. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 95 wherein the intra-set time interval is less than 1
second.
99. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the escalating alarm signal includes a
multiplicity of successive sets of alerting signals, the sets
spaced apart in time by an inter-set time interval.
100. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 99 wherein the escalating alarm signal is produced by a
progressively decreasing inter-set time interval between successive
sets of alerting signals.
101. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the escalating alarm signal includes a
multiplicity of successive sets of alerting signals, each set
including one or more alerting signals, the number of alerting
signals in each set increasing over time.
102. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 101 wherein the time interval between alerting signals in
sets of alerting signals including 2 or more alerting signals
progressively decreases over time.
103. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the escalating alarm signal includes a
multiplicity of alerting signals, the alerting signals increasing
in duration over time.
104. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the escalating alarm signal includes a
multiplicity of alerting signals, the alerting signals
progressively increasing in frequency over time.
105. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the escalating alarm signal includes an internal
alarm signal originating from an implanted medical device.
106. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 105 wherein the internal alarm signal is-includes a
vibration.
107. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 105 wherein the internal alarm signal includes an electrical
tickle.
108. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 105 wherein the internal alarm signal includes a sound.
109. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 105 further including an escalating external alarm
signal.
110. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 105 further including an external alarm signal generated by
an external alarm system is of constant level of perceptibility to
the patient.
111. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 105 further including an external alarm signal generated by
an external alarm system, the external alarm signal being initiated
at a preset time before the initiation of the escalating internal
alarm signal.
112. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 111 wherein the external alarm is an escalating alarm
signal.
113. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 105 further including an external alarm signal generated by
an external alarm system, the external alarm signal being initiated
at a preset time after the initiation of the escalating internal
alarm signal.
114. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 113 wherein the external alarm signal is an escalating alarm
signal.
115. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the escalating alarm signal includes an external
alarm signal originating from an external alarm system.
116. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 116 wherein the internal alarm signal includes a
vibration.
117. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 116 wherein the internal alarm signal includes a visual
display.
118. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 116 wherein the internal alarm signal includes a sound.
119. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 116 further including an internal alarm signal generated by
an implanted medical device, the internal alarm signal being of
constant level of perceptibility to the patient.
120. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 119 wherein the escalating external alarm signal is initiated
at a preset time before the initiation of the constant internal
alarm signal.
121. The implantable pacemaker system having the capability of
detecting cardiac events occurring in a human patient as recited in
claim 81 wherein the implantable cardiac defibrillator also
includes the capability to pace the heart of the human patient.
122. A method of sensing cardiac events occurring in a human
patient including the steps of: (a) establishing at least two
electrodes for obtaining an electrical signal from the patient's
heart; (b) providing an electrical signal processor coupled to said
electrodes for processing the electrical signal; and, (c)
generating an escalating sensory alarm signal received by the
patient over a predetermined time period subsequent to the
electrical signal processor detecting a cardiac event.
123. The method of sensing cardiac events as recited in claim 122
wherein said escalating sensory alarm signal increases in amplitude
over time only for a preset time period.
124. The method of sensing cardiac events as recited in claim 122
wherein said escalating sensory alarm signal is non-continuous for
providing successive alerting signals increasing over a
predetermined time interval.
125. The method of sensing cardiac events as recited in claim 122
wherein the step of generating the escalating alarm signal includes
the step of establishing an internal alarm signal originating from
an implanted medical device.
126. The method of sensing cardiac events as recited in claim 125
where the step of establishing the internal alarm signal includes
the step of providing a vibratory internal alarm signal.
127. The method of sensing cardiac events as recited in claim 126
where the step of establishing the internal alarm signal includes
the step providing an electrical signal tickle.
128. The method of sensing cardiac events as recited in claim 125
where the step of establishing the internal alarm signal includes
the step of providing a visual display.
Description
FIELD OF USE
[0001] This invention is in the field of implantable medical device
systems that monitor a patient's cardiovascular condition.
BACKGROUND OF THE INVENTION
[0002] Heart disease is the leading cause of death in the United
States. A heart attack (also known as an acute myocardial
infarction (AMI)) typically results from a thrombus (i.e., a blood
clot) that obstructs blood flow in one or more coronary arteries.
AMI is a common and life-threatening complication of coronary
artery disease. Coronary ischemia is caused by an insufficiency of
oxygen to the heart muscle. Ischemia is typically provoked by
physical activity or other causes of increased heart rate when one
or more of the coronary arteries is narrowed by atherosclerosis.
AMI, which is typically the result of a completely blocked coronary
artery, is the most extreme form of ischemia. Patients will often
(but not always) experience chest discomfort (angina) when the
heart muscle is experiencing ischemia. Those with coronary
atherosclerosis are at higher risk for AMI if the plaque becomes
further obstructed by thrombus.
[0003] The current treatment for a coronary artery narrowing (a
stenosis) is the insertion of a drug-eluting stent such as the
Cypher.TM. sirolimus-eluting stent from Cordis Corporation or the
Taxus.TM. paclitaxel-eluting stent from the Boston Scientific
Corporation. The insertion of a stent into a stenosed coronary
artery is a reliable medical treatment to eliminate or reduce
coronary ischernia and to prevent the complete blockage of a
coronary artery, which blockage can result in an AMI.
[0004] Acute myocardial infarction and ischemia may be detected
from a patient's electrocardiogram (ECG) by noting an ST segment
shift (i.e., voltage change). However, without knowing the
patient's normal ECG pattern, detection from a standard 12 lead ECG
can be unreliable.
[0005] Fischell et al. in U.S. Pat. Nos. 6,112,116, 6,272,379 and
6,609,023 describe implantable systems and algorithms for detecting
the onset of acute myocardial infarction and providing both patient
alerting and treatment. The Fischell et al. patents describe how
the electrical signal from inside the heart (which is called an
"electrogram") can be used to determine various states of
myocardial ischemia.
[0006] The Reveal.TM. subcutaneous loop Holter monitor sold by
Medtronic, Inc., uses two case electrodes spaced about 3 inches
apart to record electrocardiogram information. Recording can be
triggered automatically when arrhythmias are detected or upon
patient initiation using an external device. The Reveal is designed
to record electrogram data only and does not include a patient
alerting capability. The Reveal also does not have the capability
to measure or alert the patient if there is an ST segment shift. In
fact, the Reveal's high pass filtering and electrode'spacing
preclude accurate detection of changes in the low frequency aspects
of the heart's electrical signal such as the ST segment of the
electrogram.
[0007] While pacemakers and Implantable Cardioverter Defibrillators
(ICDs) monitor the patient's electrogram, they do not currently
detect ST segment changes nor provide patient alerting.
[0008] The term "medical practitioner" shall be used herein to mean
any person who might be involved in the medical treatment of a
patient. Such a medical practitioner would include, but is not
limited to, a medical doctor (e.g., a general practice physician,
an internist or a cardiologist), a medical technician, a paramedic,
a nurse or an electrogram analyst. Although the masculine pronouns
"he" and "his" are used herein, it should be understood that the
patient, physician or medical practitioner could be a man or a
woman. A "cardiac event" includes an acute myocardial infarction,
ischemia caused by effort (such as exercise) and/or an elevated
heart rate, bradycardia, tachycardia or an arrhythmia such as
atrial fibrillation, atrial flutter, ventricular fibrillation, and
premature ventricular or atrial contractions (PVCs or PACs
respectively).
[0009] It is generally understood that the term "electrocardiogram"
is defined as the heart's electrical signals sensed by means of
skin surface electrodes that are placed in a position to indicate
the heart's electrical activity (depolarization and
repolarization). An electrocardiogram segment refers to a portion
of electrocardiogram signal that extends for either a specific
length of time, such as 10 seconds, or a specific number of heart
beats, such as 10 beats. A beat is defined as a sub-segment of an
electrogram or electrocardiogram segment containing exactly one R
wave. As used herein, the PQ segment of a patient's
electrocardiogram or electrogram is the typically straight segment
of a beat of an electrocardiogram or electrogram that occurs just
before the R wave and the ST segment is a typically straight
segment that occurs just after the R wave.
[0010] Although often described as an electrocardiogram (ECG), the
electrical signal from the heart as measured from electrodes within
the body is properly termed an "electrogram". As defined herein,
the term "electrogram" is the heart's electrical signal voltage as
sensed from one or more implanted electrode(s) that are placed in a
position to indicate the heart's electrical activity
(depolarization and repolarization). An electrogram segment refers
to a portion of the electrogram signal for either a specific length
of time, such as 10 seconds, or a specific number of heart beats,
such as 10 beats. For the purposes of this specification, the terms
"detection" and "identification" of a cardiac event have the same
meaning.
[0011] A heart signal parameter is defined to be a measured or
calculated value created during the processing of one or more beats
of the electrogram (or electrocardiogram). Heart signal parameters
include the following: ST deviation (ST segment average value minus
PQ segment average value), ST shift (ST deviation compared to a
baseline average ST deviation), average signal strength, T wave
peak height, T wave average value, T wave deviation, QRS complex
width, number of PVCs per unit time, heart rate and R-R
interval.
SUMMARY OF THE INVENTION
[0012] The present invention system for the detection of coronary
ischemia (including AMI) as described herein shall be called the
"Guardian" system. The Guardian system detects cardiac events using
an implanted sub-system called a "cardiosaver system" which is
designed to detect cardiac events including arrhythmias and
coronary ischemia. A "cardiac event" can be an acute myocardial
infarction, ischemia caused by effort (such as exercise) and/or an
elevated heart rate, bradycardia, tachycardia or an arrhythmia such
as atrial fibrillation, atrial flutter, ventricular fibrillation,
and premature ventricular or atrial contractions (PVCs or PACs
respectively). The present invention cardiosaver system is designed
to detect ischemia (including AMI) by identifying ST segment
changes in a positive direction (ST elevation) or negative
direction (ST depression).
[0013] The cardiosaver system includes electrodes placed to
advantageously sense electrical signals from the heart that is the
electrogram. The electrodes can be placed within the heart and/or
subcutaneously. The implanted portion of the Guardian system is the
cardiosaver system as described by Fischell et al. in U.S. Pat.
Nos. 6,112,116, 6,272,379 and 6,609,023, each of these patents
being incorporated herein by reference. The Guardian system also
includes external equipment that can include a physician's
programmer and an external alarm device also described in the
Fischell et al. patents.
[0014] The present invention is a cardiosaver system that utilizes
techniques for patient alerting designed to ensure the patient
knows what is happening without startling the patient, which could
cause an unwanted rise in heart rate at the time of a cardiac event
when it is important to remain calm.
[0015] In the Fischell et al. patents mentioned above, the concept
of internal and external alarm signals is discussed, including the
technique of using different patterns of sound, vibration or
electrical tickle to assist the patient in differentiating between
an emergency (major or critical) alarm where immediate medical
attention is needed and a "see your doctor" alert where an
appointment should be scheduled as soon as convenient.
[0016] The present invention alerting system improves upon the
Fischell et al. concepts by using alert escalation techniques that
will communicate the emergency alarm, see doctor alert and/or other
patient alert messages without startling or scaring the patient.
One embodiment of the present invention uses an increasing
amplitude of vibration over time from an internal alarm signal
within the implanted cardiosaver. For example, the vibration
amplitude might increase over a period of several minutes until it
reaches a pre-set level. The escalating amplitude technique can
also be applied if the internal alarm uses an electrical tickle or
other means of alerting the patient. Also the present invention
Guardian system may include an increasing amplitude for the
external alarm signal generated by the external alarm system
mentioned by Fischell et al. The external alarm signal can be a
sound, vibration or visual display with sound being the preferred
embodiment.
[0017] It is also envisioned that not only can the amplitude of the
internal and/or external alarm signals be increased over time, but
the pattern and frequency of the signal might change. For example,
the internal alarm might use sets of three successive vibrations
with a short time between vibrations within a set and a longer time
between sets where the time between sets of vibrations might
decrease over time. The time between vibrations within a set might
also decrease as the alert escalates. Another example might have
the external alarm signal using a tone or tone sequence that
increases in the pitch of the tones as the alert escalates.
Finally, if a visual display using sets of light flashes is used as
the external alarm signal, then the escalation might include the
brightness of the flashes, an increase in the number of the flashes
within a set, a decrease in the time between sets and a change in
the color of the flashes.
[0018] For the purposes of this invention, the term "alarm signal"
refers to the complete signal internally or externally generated to
alert the patient to the detection of a cardiac event. An alarm
signal will continue until a timer turns it off after a pre-set
time period (e.g., 5 minutes) or an alarm silence command is
provided to the source generating the alarm. A typical alarm signal
will be made up of a sequence of short (less than 10 seconds long)
alerting signals. The alerting signals may be produced in sets with
an inter-set time interval defined as the time interval between
sets of alerting signals and the intra-set time interval defined as
the time between alerting signals within a set of alerting
signals.
[0019] So in summary, the present invention is an implanted system
for the detection of cardiac events having any combination of
internal alarm signals and external alarm signals where, over the
initial period of patient alerting, the alarm signals escalate by
any or all of the following:
[0020] a) An increase in amplitude of alerting signals over
time;
[0021] b) An increase in the number of alerting signals per
set;
[0022] c) A decrease in the time between alerting signals within a
set;
[0023] d) A decrease in the time between sets of alerting
signals;
[0024] e) A change in the frequency (vibrational frequency, sound
pitch, color) of the alerting signals; and,
[0025] f) An increase in the frequency, length and/or amplitude of
each alerting signal within a set (including a set of one alerting
signal).
[0026] Another embodiment of the present invention is an implanted
ischemia detection device with patient alerting that also includes
pacemaker circuitry to pace the patient's heart as needed. Still
another embodiment is an implanted ischemia detection device with
patient alerting that includes Implantable Cardiac Defibrillator
(ICD) circuitry to defibrillate the patient's heart as needed. Yet
another embodiment is an implanted ischemia detection device with
patient alerting that includes a combination of pacemaker and ICD
circuitry.
[0027] It is also envisioned that there could be an escalating
pattern where the number of alerting signals in each set increases
while the length of each alerting signal decreases.
[0028] It is also envisioned that the escalation of alerting might
involve the sequencing of internal and external alarms. For
example, the external alarm signal might begin first as people who
are used to phones ringing are less likely to be startled by
external alerting sounds. After a preset period of time, the
internal alarm signal might begin. Neither, either or both the
external and internal alarm signals in such a sequential activation
might use one or more alarm signals that escalate by the means
described above.
[0029] Thus it is an object of this invention to have a Guardian
system that can alert a patient to the detection of a cardiac event
without causing a startle response.
[0030] Another object of this invention is to have a Guardian
system that can alert a patient to the detection of a cardiac event
where the alarm signal escalates over time.
[0031] Still another object of this invention is to have a Guardian
system that can alert a patient to the detection of a cardiac event
where the alarm signal escalates by increasing amplitude over
time.
[0032] Still another object of this invention is to have a Guardian
system that can alert a patient to the detection of a cardiac event
where the alarm signal escalates by increasing frequency over
time.
[0033] Yet another object of this invention is to have a Guardian
system that can alert a patient to the detection of a cardiac event
where the alarm signal escalates by decreasing the time between
alerting signals within sets of the alarm signal.
[0034] Yet another object of this invention is to have a Guardian
system that can alert a patient to the detection of a cardiac event
where the alarm signal escalates by decreasing the time between
sets of alerting signals within the alarm signal.
[0035] Yet another object of this invention is to have a Guardian
system that can alert a patient to the detection of a cardiac event
where the alarm signal escalates by increasing the number of
alerting signals within sets of the alarm signal.
[0036] Yet another object of this invention is to have a Guardian
system that can alert a patient to the detection of a cardiac event
where the alarm signal escalates by increasing the frequency,
length and/or amplitude of each alerting signal with a set
(including a set of one alerting signal).
[0037] Yet another object of the present invention is to have a
Guardian system with an implanted component having the capability
to generate an internal alarm signal and an external alarm system
capable of generating an external alarm signal where the patient
alert initiates the external alarm signal before the internal
alarm.
[0038] Yet another object of the present invention is to have a
Guardian system with an implanted component having the capability
to generate an internal alarm signal and an external alarm system
capable of generating an external alarm signal where the patient
alert initiates the internal alarm signal before the external
alarm.
[0039] These and other objects and advantages of this invention
will become obvious to a person of ordinary skill in this art upon
reading of the detailed description of this invention including the
associated drawings as presented herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] FIG. 1 illustrates a Guardian system for the detection of a
cardiac event such as an ST segment shift indicative of coronary
ischemia and for warning the patient that a cardiac event is
occurring;
[0041] FIG. 2 is a block diagram of the implanted cardiosaver
system;
[0042] FIG. 3 illustrates an increase in amplitude of an alarm
signal as the patient alert escalates;
[0043] FIG. 4 illustrates a change in the number of alerting
signals per set as the patient alert escalates;
[0044] FIG. 5 illustrates a decrease in the time between alerting
signals within a set of alerting signals as the patient alert
escalates;
[0045] FIG. 6 illustrates a decrease in the time between sets of
alerting signals as the patient alert escalates;
[0046] FIG. 7 illustrates a change in frequency of alerting signals
as the patient alert escalates;
[0047] FIG. 8 illustrates a change in the length of each alerting
signal within a set of alerting signals as the patient alert
escalates;
[0048] FIG. 9 illustrates a progressive increase in the alerting
signals within each set of alerting signals of an alarm signal;
and,
[0049] FIG. 10 illustrates an escalating patient alert with
increasing intensity, increasing number of alerting signals per
set, decreasing time between alerting signals within a set and
decreasing time between sets of alerting signals.
DETAILED DESCRIPTION OF THE INVENTION
[0050] FIG. 1 illustrates one embodiment of the Guardian system 10
consisting of an implanted cardiosaver system 5 and external
equipment 7. The cardiosaver system 5 includes a cardiosaver 11, an
antenna 6 and an electrode 4 that is part of a lead 2. The
cardiosaver 11 includes electronic circuitry that can detect a
cardiac event such as an acute myocardial infarction or arrhythmia
and can warn the patient when a cardiac event occurs. The
cardiosaver 11 can store the patient's electrogram for later
readout and can send and receive wireless signals 3 to and from the
external equipment 7 via the implanted antenna 6 and the external
antenna 25. The functioning of the cardiosaver system 5 will be
explained in greater detail with the assistance of FIG. 2.
[0051] The cardiosaver system 5 has at least one lead 2 with at
least one electrode 4. In fact, the cardiosaver system 5 could
utilize as few as one lead or as many as three and each lead could
have as few as one electrode or as many as eight electrodes. The
lead 2 in FIG. 1 could advantageously be placed subcutaneously or
through the patient's vascular system with the electrode 4 being
placed into the apex of the right ventricle. For example, the lead
2 could be placed in the right ventricle or right atrium or the
superior vena cava similar to the placement of leads for pacemakers
and ICDs. The metal case of the cardiosaver 11 could serve as an
indifferent electrode with the electrode 4 being the active
electrode. Alternately, the lead 2 in FIG. 1 could be placed
through the patient's vascular system with the electrode 4 being
placed into the apex of the left ventricle.
[0052] The lead 2 could advantageously be placed subcutaneously at
any location where the electrode 4 would provide a good electrogram
signal indicative of the electrical activity of the heart. Again
for the lead 2, the case of the cardiosaver 11 of the cardiosaver
system 5 could be an indifferent electrode and the electrode 4
would be the active electrode. Although the Guardian system 10
described herein can readily'operate with only two electrodes, or
one electrode and the case of the cardiosaver being the other
electrode, it is envisioned that multiple electrodes used in
monopolar or bipolar configurations could be used.
[0053] FIG. 1 also shows the external equipment 7 that consists of
an external alarm transceiver 20, a physician's programmer 18, a
pocket PC 12, an emergency room diagnostic system 16 and the
equipment 14 in a remote diagnostic center. The external equipment
7 provides the means to interact with the cardiosaver system 5.
These interactions include programming the cardiosaver 11,
retrieving data collected by the cardiosaver system 5, and handling
alarms generated by the cardiosaver 11. It should be understood
that the cardiosaver system 5 could operate with some but not all
of the external equipment 7.
[0054] The external alarm transceiver 20 includes a battery 21, an
alarm disable/panic button 22, a radio frequency transceiver 23, a
microphone 27, an alarm-speaker 24, an antenna 25, a GPS satellite
receiver 26, and a standard interface 28 for providing wired or
wireless communication with the pocket PC 12, emergency room
diagnostic system 16, or physician's programmer 18. A long distance
voice/data communications interface 29 provides connectivity to the
remote diagnostic center equipment 14 through voice and data
telecommunications networks. For example, the microphone 27 and
speaker 24 could be used for wired or wireless telephone calls to
and from a medical practitioner at the remote diagnostic center. A
built-in modem as part of the interface 29 would allow data to be
transmitted to and from the remote diagnostic center equipment 14
over a voice connection. Alternately, a data communications
capability of the interface 29 could allow data to be sent or
received through a wired or wireless data network. The external
alarm transceiver 20 may be a separate unit that can be carried by
the patient and used by the patient's physician as the data
interface to the cardiosaver system 5 or it may also be built into
the pocket PC 12, physician's programmer 18 or emergency room
diagnostic system 16
[0055] The pocket PC also described by Fischell et al. in U.S. Pat.
No. 6,609,023 can provide the patient or physician the ability to
check the status of the cardiosaver 11 and display a limited set of
electrogram data uploaded from the cardiosaver 11.
[0056] The emergency room diagnostic system 16 is a more
sophisticated system that can upload and display any of the data
stored within the cardiosaver 11 and would, in its preferred
embodiment, use a touch screen display to facilitate triage of
patients arriving in an emergency room who have the cardiosaver
system 5. This should greatly reduce the time from arrival at the
emergency room until treatment for cardiosaver system patients
having a cardiac event.
[0057] The purpose of the physician's programmer 18 shown in FIG. 1
is to set and/or change the operating parameters of the implanted
cardiosaver system 5 and to read out data stored in the memory of
the cardiosaver 11 such as stored electrogram segments as described
by Fischell et al. in U.S. Pat. No. 6,609,023.
[0058] The external alarm transceiver 20 would typically be a
pager-sized device that the patient would carry on his person or
keep in close proximity. If a cardiac event is detected by the
cardiosaver system 5, an alarm message is sent by a wireless signal
3 to the alarm transceiver 20 via the antennas 6 and 25. When the
alarm is received by the alarm transceiver 20, a patient alerting
sound is played through the loudspeaker 24 to warn the patient that
a cardiac event has occurred. Examples of such sounds include a
periodic buzzing, a sequence of tones and/or a speech message that
instructs the patient as to what actions should be taken.
Furthermore, the alarm transceiver 20 can, depending upon the
nature of the signal 3, send an outgoing message to the remote
diagnostic center equipment 14 to alert medical practitioners that
a cardiosaver system alarm has occurred. The medical practitioners
can then utilize the voice communications capabilities of the
remote diagnostic center equipment 14 to call back the patient
similar to the call that occurs to car drivers through the ONSTAR
service when their car's air bags deploy in an accident. The
optional GPS receiver 26 would allow the data sent to the remote
diagnostic center equipment 14 to include patient location to
facilitate the summoning of emergency medical services.
[0059] The alarm disable/panic button 22 will turn off both the
internal alarm of the implant 5 and the sound being emitted from
the loudspeaker 24. If no alarm is occurring, then pressing the
alarm disable/panic button 22 will place a voice and/or data call
to the remote diagnostic center similar to the call that is placed
when the ONSTAR button is pressed in a car equipped to access the
ONSTAR service. GPS information and a subset of patient electrogram
data may be sent as well to the medical practitioners at the remote
diagnostic center. The remotely located medical practitioner could
then analyze the electrogram data and call the patient back to
offer advice as to whether there is an emergency situation or the
situation could be routinely handled by the patient's personal
physician at some later time.
[0060] FIG. 2 is a block diagram of the cardiosaver system 5. The
lead 2 includes the electrode 4 and the wire 12. The wire 12
connects the electrode 4 to the amplifier circuit 36 that is also
connected by the wire 15 to the cardiosaver case 8 acting as an
indifferent electrode. The amplified electrogram signals 37 from
the amplifier circuit 36 are converted to digital signals 38 by the
analog-to-digital converter 41. The digital electrogram signals 38
are then sent to the electrical signal processor 44. The processor
44 in conjunction with the memory 47 can process the digital
signals 38 according to the programming instructions stored in the
program memory 45. This programming (i.e. software) enables the
cardiosaver system 5 to detect the occurrence of a cardiac event
such as an ST segment elevation that is indicative of an acute
myocardial infarction.
[0061] A clock/timing sub-system 49 provides the means for timing
specific activities of the cardiosaver system 5 including the
absolute or relative time stamping of detected cardiac events. The
clock/timing sub-system 49 can also facilitate power savings by
causing components of the cardiosaver system 5 to go into a low
power stand-by mode in between times for electrogram signal
collection and processing. Such cycled power savings techniques are
often used in implantable pacemakers and defibrillators. In an
alternative embodiment, the clock/timing sub-system can be provided
by a program subroutine run by the central processing unit 44. It
is also envisioned that the processor 44 may include an integral or
external First-In-First-Out (FIFO) buffer memory to allow saving of
data from before the detection of a cardiac event.
[0062] Techniques for detecting cardiac events by the processor 44
are described by Fischell et al. in U.S. Pat. No. 6,609,023.
[0063] An important aspect of the present invention is the
filtering of the electrical signals sensed by the electrodes 4 and
8. The preferred embodiment of the present invention cardiosaver 11
(FIG. 1) will include high pass and/or low pass filtering of the
electrical signals in the amplifier circuit 36. An alternative
embodiment would introduce filtering in any one, two or all of the
following locations:
[0064] 1. a separate analog filter between the amplifier circuit 36
and analog-to-digital converter 41,
[0065] 2. a separate digital filter circuit placed between the
analog-to-digital converter 41 and the processor 44, and/or
[0066] 3. digital filtering performed by the processor 44 on the
digital signals 38.
[0067] The memory 47 includes specific memory locations for patient
data, electrogram segment data and any other relevant data.
[0068] It is envisioned that the cardiosaver system 5 could also
contain pacemaker circuitry 170 and/or defibrillator circuitry 180
similar to the cardiosaver system described by Fischell et al. in
U.S. Pat. No. 6,240,049.
[0069] The alarm sub-system 48 contains the circuitry and
transducers to produce the internal alarm signals for the
cardiosaver 11 (FIG. 1). The internal alarm signal can be a
mechanical vibration, a sound or a subcutaneous electrical tickle
or shock.
[0070] The telemetry sub-system 46 with antenna 6 provides the
cardiosaver system 5 with the means for two-way wireless
communication to and from the external equipment 7 of FIG. 1. It is
also envisioned that short-range telemetry such as that typically
used in pacemakers and defibrillators could also be applied to the
cardiosaver system 5. It is also envisioned that standard wireless
protocols such as Bluetooth and 802.11a or 802.11b might be used to
provide communication with a wider group of peripheral devices.
[0071] A magnet sensor 190 may be incorporated into the cardiosaver
system 5. The primary purpose for a magnet sensor 190 is to keep
the cardiosaver system 5 in an off condition until it is checked
out just before it is implanted into a patient. This can prevent
depletion of the battery life in the period between the time that
the cardiosaver system 5 is packaged at the factory and the day it
is implanted.
[0072] The preferred embodiment of the present invention associated
with a pacemaker/ICD or combined pacemaker/ICD would have the event
detection and alerting function integrated within the pacemaker,
ICD or combined pacemaker/ICD. It is also envisioned that the lead
might connect both to a standard pacemaker, ICD or combined
pacemaker/ICD and a cardiosaver having an electrical signal
processor for cardiac event detection and the ability to generate
an escalating patient alert.
[0073] FIG. 3 is an example of use of increasing the amplitude of
an alarm signal to provide an escalating patient alert. FIG. 3
shows the progression over time of the three successive sets of
alerting signals 31, 32 and 33 of the alarm signal 30. The pattern
displayed in FIG. 3 can be applied to internal and/or external
alarm signals using vibration, sound, electrical stimulation
(tickle) or a visual display. The set 31 has alerting signals 31A,
31B and 31C, each alerting signal within the set 31 having an
amplitude 315, a duration 316, and a time interval between the
alerting signals 31A and 31B and the alerting signals 31B and 31C
of 311. The set 32 has alerting signals 32A, 32B and 32C, each
alerting signal within the set 32 having an amplitude 325, a
duration 326 and a time interval between the alerting signals 32A
and 32B and the alerting signals 32B and 32C of 321. The set 33 has
alerting signals 33A, 33B and 33C, each alerting signal within the
set 33 having an amplitude 335, a duration 336 and a time interval
between the alerting signals 33A and 33B and the alerting signals
33B and 33C of 331. The time interval between the sets 31 and 32 is
312 and the time interval between the sets 32 and 33 is 323. It can
be seen that the alarm signal 30 provides an escalating patient
alert by progressively increasing the amplitude over time as the
amplitude 335 is greater than the amplitude 325 which is greater
than the amplitude 315. Ideally, such an escalating amplitude alert
would start at level barely detectable by the patient and increase
to a level that cannot be ignored. The physician's programmer 18 of
FIG. 1 would typically provide the capability to test different
patterns and intensities of both internal and external alarm
signals with the patient to set a patient alert that cannot be
missed while also reducing the potential to startle the patient. It
is also envisioned that the amplitude might also increase for
successive alerting signals within a set. The present invention
includes any increase in amplitude over time in any type of
internal or external alarm signal. It is also envisioned that after
a preset escalation period, the amplitude would reach a pre-set
level and no longer increase. An important feature of the
programmer 18 would be to set the initial alerting signal amplitude
so that it is just barely perceptible and to set the highest
alerting signal amplitude at a level that cannot be missed.
Although FIG. 3 shows a constant duration of the alerting signals
(316, 326 and 336), a constant time between sets (312 and 323) and
constant times between alerting signals within a set (311, 321 and
331) they need not be constant. The times between alerting signals
311, 321 and 322 are typically less than one second while the times
between sets 312 and 323 are typically greater than one second.
[0074] FIG. 4 is an example of use of increasing number of alerting
signals within each set of alerting signals of an alarm signal to
provide an escalating patient alert. FIG. 4 shows the progression
over time of the four successive sets of alerting signals 41, 42,
43 and 44 of the alarm signal 40. The pattern displayed in FIG. 4
can be applied to internal and/or external alarm signals using
vibration, sound, electrical stimulation (tickle) or a visual
display. The set 41 has one alerting signal 41A, the alerting
signal 41A having an amplitude 45 and a duration 46. The set 42 has
two alerting signals 42A and 42B, each alerting signal within the
set 42 having an amplitude 45, a duration 46 and a time interval
between the alerting signals 42A and 42B of 421. The set 43 has
three alerting signals 43A, 43B and 43C, each alerting signal
within the set 43 having an amplitude 45, a duration 46 and a time
interval between the alerting signals 43A and 43B and the alerting
signals 43B and 43C of 431. The set 44 has four alerting signals
44A, 44B, 44C and 44D, each alerting signal within the set 44
having an amplitude 45, a duration 46, and a time interval between
the alerting signals 44A and 44B, the alerting signals 44B and 44C,
and the alerting signals 44C and 44D of 44. The time interval
between the sets 41 and 42 is 412, the time interval between the
sets 42 and 43 is 423, the time interval between the sets 43 and 44
is 434. It can be seen that the alarm signal 40 provides an
escalating patient alert by progressively increasing the number of
alerting signals per set over time.
[0075] Although the pattern shown in FIG. 4 shows an increase by
one of the number of alerting signals in successive sets, it is
envisioned that an increase in the number of alerting signals per
set could occur faster, e.g. an increase by two from one set to the
next. It is also envisioned that the increase in the number of
alerting signals per set could occur more slowly, e.g. an increase
by one after every two sets. Ideally, such an escalating alert
would start with a single alerting signal in a set such as the set
41 and increase to a preset number of alerting signals per set. The
present invention includes any progressive increase in the number
of alerting signals per set in an internal or external alarm
signal. It is also envisioned that after a preset escalation
period, the number of alerting signals per set would reach a
pre-set level and no longer increase. Although FIG. 4 shows a
constant amplitude 45, a constant duration of the alerting signals
46, a constant time between sets (412,423 and 434) and constant
times between alerting signals within a set (421, 431 and 441),
they need not be constant. The times between alerting signals 421,
431 and 441 are typically less than one second while the times
between sets 412, 423 and 434 are typically greater than one
second. It is also envisioned that as the number of alerting
signals within a set increases, the duration 46 of the alerting
signals might decrease. This will subsequently reduce the total
time for sets of alerting signals as the number of alerting signals
increases.
[0076] FIG. 5 is an example of use of decreasing time between
alerting signals within a set of alerting signals of an alarm
signal to provide an escalating patient alert. FIG. 5 shows the
progression over time of the three successive sets of alerting
signals 51, 52 and 53 of the alarm signal 50. The pattern displayed
in FIG. 5 can be applied to internal and/or external alarm signals
using vibration, sound, electrical stimulation (tickle) or a visual
display. The set 51 has alerting signals 51A, 51B and 51C, each
alerting signal within the set 51 having an amplitude 55, a
duration 516 and a time interval between the alerting signals 51A
and 51B and the alerting signals 51B and 51C of 511. The set 52 has
alerting signals 52A, 52B and 52C, each alerting signal within the
set 52 having an amplitude 55, a duration 526 and a time interval
between the alerting signals 52A and 52B and the alerting signals
52B and 52C of 521. The set 53 has alerting signals 53A, 53B and
53C, each alerting signal within the set 53 having an amplitude 55,
a duration 536 and a time interval between the alerting signals 53A
and 53B and the alerting signals 53B and 53C of 531. The time
interval between the sets 51 and 52 is 512 and the time interval
between the sets 52 and 53 is 523. It can be seen that the alarm
signal 50 provides an escalating patient alert by progressively
decreasing the time between alerting signals within successive sets
over time as the time 511 is greater than the time 521 which is
greater than the time 531. It is also envisioned that the time
between alerting signals might decrease for successive alerting
signals within a set. The present invention includes any
progressive decrease in the time between successive alerting
signals in an internal or external alarm signal. It is also
envisioned that after a preset escalation period, the time between
alerting signals would reach a pre-set level and no longer
decrease. Although FIG. 5 shows a constant amplitude 55, a constant
duration of the alerting signals (516, 526 and 536) and a constant
time between sets (512 and 523) they need not be constant. The
times between alerting signals 511, 521 and 531 are typically less
than the times between sets 512 and 523.
[0077] FIG. 6 is an example of use of decreasing time between sets
of alerting signals of an alarm signal to provide an escalating
patient alert. FIG. 6 shows the progression over time of the four
successive sets of alerting signals 61, 62, 63 and 64 of the alarm
signal 60. The pattern displayed in FIG. 6 can be applied to
internal and/or external alarm signals using vibration, sound,
electrical stimulation (tickle) or a visual display. The set 61 has
alerting signals 61A and 61B, each alerting signal within the set
61 having an amplitude 65, a duration 616 and a time interval
between the alerting signals 61A and 61B of 611. The set 62 has
alerting signals 62A and 62B, each alerting signal within the set
62 having an amplitude 65, a duration 626 and a time interval
between the alerting signals 62A and 62B of 621. The set 63 has
alerting signals 63A and 63B, each alerting signal within the set
63 having an amplitude 65, a duration 636 and a time interval
between the alerting signals 63A and 63B of 631. The set 64 has
alerting signals 64A and 64B, each alerting signal within the set
64 having an amplitude 65, a duration 646 and a time interval
between the alerting signals 64A and 64B of 641. The time interval
between the sets 61 and 62 is 612, the time interval between the
sets 62 and 63 is 623 and the time interval between the sets 63 and
64 is 634. It can be seen that the alarm signal 60 provides an
escalating patient alert by progressively decreasing the time
between sets of alerting signals over time as the time 612 is
greater than the time 623 which is greater than the time 634. The
present invention includes any progressive decrease in the time
between successive sets of alerting signals in an internal or
external alarm signal. It is also envisioned that after a preset
escalation period, the time between sets of alerting signals would
reach a pre-set level and no longer decrease. Although FIG. 6 shows
a constant amplitude 65, a constant duration of the alerting
signals (616, 626, 636 and 646) and a constant time between
alerting signals within each set (611, 621, 631 and 641), they need
not be constant. The times between alerting signals 611, 621, 631
and 641 are typically less than the times between sets 612, 623 and
634.
[0078] FIG. 7 is an example of use of increasing frequency
(decrease in wavelength) for successive sets of alerting signals of
an alarm signal to provide an escalating patient alert. FIG. 7
shows the progression over time of the three successive sets of
alerting signals 71, 72 and 73 of the alarm signal 70. The pattern
displayed in FIG. 7 can be applied to internal and/or external
alarm signals using vibration, sound, electrical stimulation
(tickle) or a visual display. For a visual display a change in
frequency would typically entail a change in color. The set 71 has
alerting signals 71A and 71B, each alerting signal within the set
71 having a wavelength 717, an amplitude 75, a duration 716 and a
time interval between the alerting signals 71A and 71B of 711. The
set 72 has alerting signals 72A and 72B, each alerting signal
within the set 72 having a wavelength 727, an amplitude 75, a
duration 726 and a time interval between the alerting signals 72A
and 72B of 721. The set 73 has alerting signals 73A and 73B, each
alerting signal within the set 73 having a wavelength 737, an
amplitude 75, a duration 736 and a time interval between the
signals 73A and 73B of 731. The time interval between the sets 71
and 72 is 712 and the time interval between the sets 72 and 73 is
723. It can be seen that the alarm signal 70 provides an escalating
patient alert by progressively decreasing the wavelength
(increasing the frequency) of the alerting signals within
successive sets over time as the wavelength 717 is greater than the
wavelength 727 which is greater than the wavelength 737. It is also
envisioned that the wavelength of the alerting signals might
progressively decrease for successive alerting signals within a
set. The present invention includes any use of a progressive
decrease in the wavelength (which is equivalent to an increase in
frequency) of alerting signals in an internal or external alarm
signal. It is also envisioned that after a preset escalation
period, the frequency of the alerting signals would reach a pre-set
level and no longer change. Although FIG. 7 shows a constant
amplitude 75, a constant duration of the alerting signals (716, 726
and 736), a constant time between alerting signals within each set
(711, 721, and 731) and a constant time between sets (712 and 723),
they need not be constant. The times between alerting signals 711,
721 and 731 are typically less than the times between sets 712 and
723. Although the alerting signals 71A, 71B, 72A, 72B, 73A and 73B
as well as all of the alerting signals for FIGS. 2 through 6 are
shown as square waves, it is envisioned that any wave structure
including sine waves and triangular waves could be used by the
cardiosaver system 5 of FIG. 1.
[0079] FIG. 8 is an example of use of progressively increasing the
duration of the alerting signals for successive sets of alerting
signals of an alarm signal to provide an escalating patient alert.
FIG. 8 shows the progression over time of the three successive sets
of alerting signals 81, 82 and 83 of the alarm signal 80. The
pattern displayed in FIG. 8 can be applied to internal and/or
external alarm signals using vibration, sound, electrical
stimulation (tickle) or a visual display. The set 81 has alerting
signals 81A and 81B, each alerting signal within the set 81 having
an amplitude 85, a duration 816 and a time interval between the
alerting signals 81A and 81B of 811. The set 82 has alerting
signals 82A and 82B, each alerting signal within the set 82 having
an amplitude 85, a duration 826 and a time interval between the
alerting signals 82A and 82B of 821. The set 83 has alerting
signals 83A and 83B each alerting signal within the set 83 having
an amplitude 85, a duration 836 and a time interval between the
alerting signals 83A and 83B of 831. The time interval between the
sets 81 and 82 is 812 and the time interval between the sets 82 and
83 is 823. It can be seen that the alarm signal 80 provides an
escalating patient alert by progressively increasing the duration
of the alerting signals for successive sets over time as the
duration 836 is greater than the duration 826 which is greater than
the duration 816. It is also envisioned that the duration of
alerting signals might increase for successive alerting signals
within a set. The present invention includes any progressive
increase in the duration of alerting signals in an internal or
external alarm signal. It is also envisioned that after a preset
escalation period, the duration of the alerting signals would reach
a pre-set level and no longer increase. Although FIG. 8 shows a
constant amplitude 85, a constant time between alerting signals
within each set (811, 821 and 831) and a constant time between sets
(812 and 823) they need not be constant. The times between alerting
signals 811, 821 and 831 are typically less than the times between
sets 812 and 823.
[0080] FIG. 9 is an alternative to the alarm signal 30 of FIG. 3 as
an example of use of increasing amplitude of an alarm signal to
provide an escalating patient alert. FIG. 9. shows the progression
over time of the three successive sets of alerting signals 91, 92
and 93 of the alarm signal 90. The pattern displayed in FIG. 9 can
be applied to internal and/or external alarm signals using
vibration, sound, electrical stimulation (tickle) or a visual
display. The set 91 has alerting signals 91A, 91B and 91C with
amplitudes 915A, 915B and 915C respectively. Each alerting signal
within the set 91 has a duration 916 and a time interval between
the alerting signals 91A and 91B and the alerting signals 91B and
91C of 911. The set 92 has alerting signals 92A, 92B and 92C with
amplitudes 925A, 925B and 925C respectively. Each alerting signal
within the set 92 has a duration 926 and a time interval between
the alerting signals 92A and 92B and the alerting signals 92B and
92C of 921. The set 93 has alerting signals 93A, 93B and 93C with
amplitudes 935A, 935B and 935C respectively. Each alerting signal
within the set 93 has a duration 936 and a time interval between
the alerting signals 93A and 93B and the alerting signals 93B and
93C of 931. The time interval between the sets 91 and 92 is 912 and
the time interval between the sets 92 and 93 is 923. It can be seen
that the alarm signal 90 provides an escalating patient alert by
progressively increasing the amplitude over time as the amplitude
increases with each successive alerting signal within each set,
e.g. 915C is greater than the amplitude 915B which is greater than
the amplitude 915A. There is also shown a progressive increase in
amplitude between sets 91, 92 and 93. Ideally, such an escalating
amplitude alert would start at level barely detectable by the
patient and increase to a level that cannot be ignored. The
physician's programmer 18 of FIG. 1 would typically provide the
capability to test different patterns and intensities of both
internal and external alarm signals with the patient to set a
patient alert that cannot be missed while also reducing the
potential to startle the patient. It is also envisioned that after
a pre-set escalation period, the amplitude would reach a pre-set
level and no longer increase. Although FIG. 9 shows a constant
duration of the alerting signals (916, 926 and 936), a constant
time between sets (912 and 923) and constant times between alerting
signals within a set (911, 921 and 931) they need not be constant.
The times between alerting signals 911, 921 and 931 are typically
less than one second while the times between sets 912 and 923 are
typically greater than one second.
[0081] FIG. 10 is an example of use of a combination of progressive
escalating features of an alarm signal to provide an escalating
patient alert. FIG. 10 shows the progression over time of the three
successive sets of alerting signals 101, 102 and 103 of the alarm
signal 100. The pattern displayed in FIG. 10 can be applied to
internal and/or external alarm signals using vibration, sound,
electrical stimulation (tickle) or a visual display. The set 101
has two alerting signals 101A and 101B, each alerting signal within
the set 101 having an amplitude 1015, a duration 1016 and a time
interval between the alerting signals 101A and 101B of 1011. The
set 102 has three alerting signals 102A, 102B and 102C, each
alerting signal within the set 102 having an amplitude 1025, a
duration 1026 and a time interval between the alerting signals 102A
and 102B and the alerting signals 102B and 102C of 1021. The set
103 has four alerting signals 103A, 103B, 103C and 103D, each
alerting signal within the set 103 having an amplitude 1035, a
duration 1036 and a time interval between the alerting signals 103A
and 103B, the alerting signals 103B and 103C and the alerting
signals 103C and 103D of 1031. The time interval between the sets
101 and 102 is 1012 and the time interval between the sets 102 and
103 is 1023. It can be seen that the alarm signal 100 provides an
escalating patient alert by combining several of the escalating
features seen in FIGS. 3 though 7 including: [0082] a)
progressively increasing the amplitude of the alerting signals over
time as the amplitude 1035 is greater than the amplitude 1025 which
is greater than the amplitude 1015; [0083] b) progressively
increasing the number of alerting signals in each set as the set
101 contains two alerting signals, the set 102 contains 3 alerting
signals and the set 103 contains 4 alerting signals; [0084] c)
progressively decreasing the time interval between alerting signals
within each set as the time interval 1011 is greater than the time
interval 1021 which is greater than the time interval 1031; and,
[0085] d) progressively decreasing the time interval between sets
of alerting signals as the time interval 1012 is greater than the
time interval 1023,
[0086] Although the alarm signal 100 shows a combination of four
different escalation features of the alarm signals 30, 40, 50 and
60, it is envisioned that an escalating signal could include any
combination of two, three or more of the escalation techniques
shown in the examples of FIGS. 3 through 10. It is also envisioned
that the present invention would also include any escalating
alerting pattern that would over time become more and more
perceptible to a patient.
[0087] Although the techniques for escalating patient alerting has
been discussed with respect to an implanted system for the
detection of cardiac events, it is also envisioned that these
techniques are equally applicable to systems for the detection of
cardiac events that are entirely external to the patient. For
clarity, the time interval between alerting signals within a set is
hereby termed as the intra-set time interval and the time interval
between sets of alerting signals is hereby termed the inter-set
time interval.
[0088] Various other modifications, adaptations, and alternative
designs are of course possible in light of the above teachings.
Therefore, it should be understood at this time that, within the
scope of the appended claims, the invention can be practiced
otherwise than as specifically described herein.
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