EP0175734A1 - Cardiac monitors - Google Patents

Cardiac monitors

Info

Publication number
EP0175734A1
EP0175734A1 EP85901485A EP85901485A EP0175734A1 EP 0175734 A1 EP0175734 A1 EP 0175734A1 EP 85901485 A EP85901485 A EP 85901485A EP 85901485 A EP85901485 A EP 85901485A EP 0175734 A1 EP0175734 A1 EP 0175734A1
Authority
EP
European Patent Office
Prior art keywords
alarm
cardiac
timing means
monitor
patient
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP85901485A
Other languages
German (de)
French (fr)
Inventor
Maria Cardiac Recorders Limited SPENCER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cardiac Recorders Ltd
Original Assignee
Cardiac Recorders Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cardiac Recorders Ltd filed Critical Cardiac Recorders Ltd
Publication of EP0175734A1 publication Critical patent/EP0175734A1/en
Pending legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
    • A61B5/316—Modalities, i.e. specific diagnostic methods
    • A61B5/318—Heart-related electrical modalities, e.g. electrocardiography [ECG]
    • A61B5/33—Heart-related electrical modalities, e.g. electrocardiography [ECG] specially adapted for cooperation with other devices
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/024—Detecting, measuring or recording pulse rate or heart rate
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
    • A61B5/316—Modalities, i.e. specific diagnostic methods
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
    • A61B5/316—Modalities, i.e. specific diagnostic methods
    • A61B5/318—Heart-related electrical modalities, e.g. electrocardiography [ECG]
    • A61B5/346—Analysis of electrocardiograms
    • A61B5/349—Detecting specific parameters of the electrocardiograph cycle
    • A61B5/363—Detecting tachycardia or bradycardia

Definitions

  • This invention relates to cardiac monitors, in particular for long-term monitoring of patients, for example in intensive care or coronary care units, operating theatres, and pace maker clinics.
  • an alarm is generated if the patient goes into rate alarm, usually an audible alarm.
  • the bleep commonly produced by a monitor in step with the heart beats is replaced by a continuous tone when the monitor detects cardiac arrest.
  • a cardiac monitor is fitted with timing means arranged to provide an indication of the time that has elapsed from the beginning of a rate alarm.
  • the time indication can for example be presented on a CRT screen of the monitor, instead of or in addition to the conventional display of heart beat and numerical pulse rate, or alternatively a separate time display can be provided.
  • the timing means is preferably arranged so that it can be reset to zero either manually, or automatically when the patient is in normal heart rhythm, for example after a certain length of time in normal rhythm or after a certain number of beats in normal rhythm.
  • the timing means is so arranged that if the patient is resuscitated but relapses into rate alarm soon after resuscitation, the timing means will measure and display the total time spent in the successive episodes of rate alarm. Accordingly, re-setting of the timing means may be rendered ineffective for a predetermined delay after normal heart rhythm has been restored.
  • Cardiac monitors commonly include a rate meter for determining the heart beat rate, controls for setting beat rates at which alarms are given, and a comparator which triggers the alarm when the measured rate reaches a predetermined value. Conveniently, this comparator also triggers the operation of the timing means, both to initiate timing and for automatic resetting when normal heart rhythm has been restored.
  • Figure 1 is a block diagram of a cardiac monitor incorporating timing means, according to the present invention
  • Figure 2 is a block diagram of a particular cardiac monitor to which the invention is applicable.
  • the monitor has an ECG amplifier 2 connected to suitable ECG electrodes 1 and providing an output to a QRS detector 3 which detects successive beats of the patient's heart.
  • the QRS detector provides outputs to a heart rate meter 4, and also to display control circuitry 5.
  • the rate meter 4 provides an output voltage proportional to the mean heart rate, which is also supplied to the display control circuitry.
  • the monitor also includes control logic 6, providing timing signals and other controlling signals for the display control circuitry, such that the latter controls the display on a built-in CRT display unit 7.
  • the display may for example comprise upper and lower traces showing the heart beat wave form as a cascaded rolling display.
  • the lower trace can be frozen, or the upper trace can be transferred to the lower trace and held frozen, to permit close examination of an. event appearing on either trace.
  • a three-digit display of the heart rate determined by the rate meter appears above the upper trace, together with symbols indicating that a QRS has been detected, or a lead or electrode fault, or the presence of heart pacemaker pulses.
  • the monitor may also include means for synchronous defibrillation in conjunction with a defibrillator.
  • the features described above are known, for example in the "Cardiorater CR7" monitor made by Cardiac Recorders Ltd.
  • the monitor also includes a loudspeaker or other sound source 11, connected to the QRS detector so as to produce a bleep each time a QRS (heartbeat) is detected.
  • the rate meter 4 is connected to an alarm comparator 8 in which the signal representing the heart rate is compared with upper and lower alarm levels manually set by controls indicated generally by the reference numeral 9, for example slide potentiometer controls provided with scales calibrated in beats per minute on the front panel of the monitor. If the measured heart rate falls outside the range between the upper and lower set levels, the comparator 8 provides an output signal to the sound source 11 so that the latter produces a continuous alarm tone.
  • the alarm is delayed from the onset of the alarm condit ion , f or example by seven seconds, and if the alarm state ceases within this delay no alarm is given. The alarm ceases when the alarm state ceases.
  • the alarm can be turned off, by moving the "low" alarm control to its lowest position.
  • the signal from the alarm comparator is also applied to a timer 10 of any convenient type, so that the latter starts timing from the onset of an alarm condition.
  • the timer provides an output signal which is used to generate a display of elapsed time, either on the CRT display unit 7, or on a separate timer display. This provides a direct indication of the length of time for which the patient has been in a state of rate alarm. Since the patient must be resuscitated within about four minutes to avoid brain damage, knowledge of the duration of the rate alarm is extremely important to those attempting resuscitation.
  • the timer When the state of rate alarm has ended, the timer will stop and its display may remain on the screen for a limited time.
  • the recorded time is held in the timer long enough to ensure that if the patient's heart stops again after a short time, the timer will resume counting from the previously recorded time so that it will display the total time for which the heart has been stopped in two or more successive episodes.
  • the timer is reset to zero manually or automatically when the heartbeat has been restored to a normal rhythm for a predetermined time or a predetermined number of beats.
  • the monitor may be provided with a reset button providing a reset input to the timer, this input also being connected to the comparator 8 to reset the timer when the comparator no longer provides an alarm signal.
  • a reset delay 12 may be included in the reset signal path.
  • Figure 2 shows a block diagram of the above-mentioned, "cardiorater CR7" monitor, together with the cardiac arrest timer according to the present invention.
  • This block diagram is believed to be self-explanatory and therefore is no described in detail.
  • the alarm can be turned off manually. Staff may well forget to turn it on again when the patient has been resuscitated.
  • the monitor may be provided with means for restoring the alarm circuitry to its previous operating condition automatically when the heartbeat has returned to a normal rhythm, either after a predetermined time or after a predetermined number, for example ten to twenty, of R waves.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Cardiology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Molecular Biology (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Physics & Mathematics (AREA)
  • Medical Informatics (AREA)
  • Biophysics (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Physiology (AREA)
  • Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)

Abstract

Un moniteur cardiaque comporte un compteur de fréquence des battements du coeur (4), une alarme comme un haut-parleur (11) et un comparateur (8) actionnant l'alarme lorsque le pouls est anormal, en particulier lors d'un arrêt cardiaque. Afin de permettre au personnel de connaître la durée de l'ârret cardiaque, le comparateur d'alarme déclanche également une horloge (10). L'horloge peut être remise à zéro manuellement ou automatiquement après rétablissement du rythme cardiaque normal. Un dispositif de retard (12) est prévu, si bien que l'horloge ne peut être remise à zéro qu'après un certain délais suivant la ressuscitation du patient. Par conséquent, si le patient a une rechute peu après la ressuscitation, l'horloge mesure la durée totale de l'arrêt cardiaque.A heart monitor has a heartbeat rate counter (4), an alarm such as a speaker (11), and a comparator (8) that activates the alarm when the pulse is abnormal, particularly during cardiac arrest . In order to allow staff to know the duration of the cardiac arrest, the alarm comparator also starts a clock (10). The clock can be reset manually or automatically after a return to normal heart rate. A delay device (12) is provided so that the clock can only be reset after a certain delay following the resuscitation of the patient. Therefore, if the patient has a relapse soon after resuscitation, the clock measures the total duration of the cardiac arrest.

Description

CARDIAC MONITORS
BACKGROUND OF THE INVENTION.
This invention relates to cardiac monitors, in particular for long-term monitoring of patients, for example in intensive care or coronary care units, operating theatres, and pace maker clinics.
In conventional cardiac monitors, an alarm is generated if the patient goes into rate alarm, usually an audible alarm. For example, the bleep commonly produced by a monitor in step with the heart beats is replaced by a continuous tone when the monitor detects cardiac arrest.
A serious disadvantage of known monitors is that the attending staff have no way of knowing how long the patient has been in a state of rate alarm, and therefore do not know how much time they have left to resuscitate the patient before brain damage occurs. SUMMARY OF THE INVENTION.
According to the present invention, a cardiac monitor is fitted with timing means arranged to provide an indication of the time that has elapsed from the beginning of a rate alarm.
The time indication can for example be presented on a CRT screen of the monitor, instead of or in addition to the conventional display of heart beat and numerical pulse rate, or alternatively a separate time display can be provided.
The timing means is preferably arranged so that it can be reset to zero either manually, or automatically when the patient is in normal heart rhythm, for example after a certain length of time in normal rhythm or after a certain number of beats in normal rhythm.
Preferably the timing means is so arranged that if the patient is resuscitated but relapses into rate alarm soon after resuscitation, the timing means will measure and display the total time spent in the successive episodes of rate alarm. Accordingly, re-setting of the timing means may be rendered ineffective for a predetermined delay after normal heart rhythm has been restored. Cardiac monitors commonly include a rate meter for determining the heart beat rate, controls for setting beat rates at which alarms are given, and a comparator which triggers the alarm when the measured rate reaches a predetermined value. Conveniently, this comparator also triggers the operation of the timing means, both to initiate timing and for automatic resetting when normal heart rhythm has been restored.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are shown in the accompanying drawings, in which:
Figure 1 is a block diagram of a cardiac monitor incorporating timing means, according to the present invention, and Figure 2 is a block diagram of a particular cardiac monitor to which the invention is applicable.
DESCRIPTION OF PREFERRED EMBODIMENTS
The monitor has an ECG amplifier 2 connected to suitable ECG electrodes 1 and providing an output to a QRS detector 3 which detects successive beats of the patient's heart.
The QRS detector provides outputs to a heart rate meter 4, and also to display control circuitry 5. The rate meter 4 provides an output voltage proportional to the mean heart rate, which is also supplied to the display control circuitry.
The monitor also includes control logic 6, providing timing signals and other controlling signals for the display control circuitry, such that the latter controls the display on a built-in CRT display unit 7.
The display may for example comprise upper and lower traces showing the heart beat wave form as a cascaded rolling display. The lower trace can be frozen, or the upper trace can be transferred to the lower trace and held frozen, to permit close examination of an. event appearing on either trace. A three-digit display of the heart rate determined by the rate meter appears above the upper trace, together with symbols indicating that a QRS has been detected, or a lead or electrode fault, or the presence of heart pacemaker pulses.
The monitor may also include means for synchronous defibrillation in conjunction with a defibrillator.
The features described above are known, for example in the "Cardiorater CR7" monitor made by Cardiac Recorders Ltd. The monitor also includes a loudspeaker or other sound source 11, connected to the QRS detector so as to produce a bleep each time a QRS (heartbeat) is detected.
To provide an alarm, the rate meter 4 is connected to an alarm comparator 8 in which the signal representing the heart rate is compared with upper and lower alarm levels manually set by controls indicated generally by the reference numeral 9, for example slide potentiometer controls provided with scales calibrated in beats per minute on the front panel of the monitor. If the measured heart rate falls outside the range between the upper and lower set levels, the comparator 8 provides an output signal to the sound source 11 so that the latter produces a continuous alarm tone. The alarm is delayed from the onset of the alarm condit ion , f or example by seven seconds, and if the alarm state ceases within this delay no alarm is given. The alarm ceases when the alarm state ceases. The alarm can be turned off, by moving the "low" alarm control to its lowest position.
The signal from the alarm comparator is also applied to a timer 10 of any convenient type, so that the latter starts timing from the onset of an alarm condition. The timer provides an output signal which is used to generate a display of elapsed time, either on the CRT display unit 7, or on a separate timer display. This provides a direct indication of the length of time for which the patient has been in a state of rate alarm. Since the patient must be resuscitated within about four minutes to avoid brain damage, knowledge of the duration of the rate alarm is extremely important to those attempting resuscitation.
When the state of rate alarm has ended, the timer will stop and its display may remain on the screen for a limited time. The recorded time is held in the timer long enough to ensure that if the patient's heart stops again after a short time, the timer will resume counting from the previously recorded time so that it will display the total time for which the heart has been stopped in two or more successive episodes.
The timer is reset to zero manually or automatically when the heartbeat has been restored to a normal rhythm for a predetermined time or a predetermined number of beats. Thus, the monitor may be provided with a reset button providing a reset input to the timer, this input also being connected to the comparator 8 to reset the timer when the comparator no longer provides an alarm signal. To prevent the timer from being reset too soon, in case the heart stops again, a reset delay 12 may be included in the reset signal path. The circuitry of the block diagram is not illustrated in detail, since circuit elements capable of performing the required functions will readily suggest themselves to the skilled reader.
By way of example only, to illustrate a practical heart monitor system, Figure 2 shows a block diagram of the above-mentioned, "cardiorater CR7" monitor, together with the cardiac arrest timer according to the present invention. This block diagram is believed to be self-explanatory and therefore is no described in detail.
As mentioned above, the alarm can be turned off manually. Staff may well forget to turn it on again when the patient has been resuscitated. The monitor may be provided with means for restoring the alarm circuitry to its previous operating condition automatically when the heartbeat has returned to a normal rhythm, either after a predetermined time or after a predetermined number, for example ten to twenty, of R waves.

Claims

CLAIMS :
1. A cardiac monitor incorporating an alarm arranged to operate on detection of abnormal heart action, and further incorporating timing means arranged to provide an indication of the time elapsed from initial operation of the alarm.
2. A cardiac monitor incorporating an alarm arranged to operate if a patient being monitored suffers cardiac arrest, and timing means arranged to provide an indication of the time that has elapsed from the beginning of cardiac arrest.
3. A cardiac monitor as claimed in claim 2 in which the timing means is so arranged that if the patient is resuscitated but relapses into cardiac arrest soon after resuscitation, the timing means will measure and display the total time spent in the successive episodes of cardiac arrest.
4. A cardiac monitor as claimed in claim 3 including means for resetting the timing means, the resetting means being ineffective for a predetermined delay after restoration of normal heart rhythm.
5. A cardiac monitor as claimed in claim 1, 2 or 3 including means for manually or automatically resetting the timing means to zero.
6. A cardiac monitor as claimed in any preceding claim including a comparator which triggers the alarm when the measured heartbeat rate reaches a predetermined value and also tr iggers operation of the timing means.
EP85901485A 1984-03-20 1985-03-19 Cardiac monitors Pending EP0175734A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8407155 1984-03-20
GB08407155A GB2156124B (en) 1984-03-20 1984-03-20 Cardiac monitors

Publications (1)

Publication Number Publication Date
EP0175734A1 true EP0175734A1 (en) 1986-04-02

Family

ID=10558336

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85901485A Pending EP0175734A1 (en) 1984-03-20 1985-03-19 Cardiac monitors

Country Status (5)

Country Link
EP (1) EP0175734A1 (en)
JP (1) JPS61501493A (en)
DK (1) DK531485A (en)
GB (1) GB2156124B (en)
WO (1) WO1985004087A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6726634B2 (en) * 2002-01-25 2004-04-27 Koninklijke Philips Electronics N.V. System and method for determining a condition of a patient
CN105852840A (en) * 2016-04-25 2016-08-17 珠海格力电器股份有限公司 Heart rhythm monitoring equipment
JP2020036733A (en) * 2018-09-04 2020-03-12 フクダ電子株式会社 Biological information management system and terminal device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1224904A (en) * 1968-08-09 1971-03-10 John Stewart Simpson Stewart Improvements in and relating to electromedical apparatus
US3680084A (en) * 1970-08-03 1972-07-25 Denis Franklin Status display panel indicating performance as a function of time with record feature
US4129125A (en) * 1976-12-27 1978-12-12 Camin Research Corp. Patient monitoring system
US4276888A (en) * 1978-10-26 1981-07-07 Smith Charles A Vital function monitor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8504087A1 *

Also Published As

Publication number Publication date
GB2156124A (en) 1985-10-02
GB2156124B (en) 1987-10-14
DK531485A (en) 1986-01-03
GB8407155D0 (en) 1984-04-26
DK531485D0 (en) 1985-11-18
JPS61501493A (en) 1986-07-24
WO1985004087A1 (en) 1985-09-26

Similar Documents

Publication Publication Date Title
US3144019A (en) Cardiac monitoring device
US5285792A (en) System for producing prioritized alarm messages in a medical instrument
CA1060102A (en) Cardiac pacer system
US4527567A (en) Method and apparatus for automatically evaluating the quality of the performance of a cardiac pacing system
US4202340A (en) Method and apparatus for monitoring heart activity, detecting abnormalities, and cardioverting a malfunctioning heart
US4667682A (en) Cardiac ambulatory monitor
US3698386A (en) Cardiac rhythm computer device
US4457315A (en) Cardiac arrhythmia detection and recording
US5058599A (en) Method and apparatus for detecting a sequence of abnormal events in an electrical signal, particularly in the depolarization signal of a heart
US3495584A (en) Lead failure detection circuit for a cardiac monitor
US6438411B1 (en) Digital ECG detection system
Vetter et al. Comparison of arrhythmia computer and conventional monitoring in coronary-care unit
US3584618A (en) A system and method for monitoring a progressive sequence of physiological conditions
JPS6139064B2 (en)
US5955956A (en) Audible alarm system for an automated external defibrillator
GB2083363A (en) Automatic defibrillator
US3651799A (en) System for mutually exclusive monitoring of natural heartbeat and pacer-stimulated heartbeat
US3554188A (en) Heartbeat frequency monitor
US4096865A (en) Method and apparatus for monitoring a timed failure condition relationship in a cardiac pacer
EP0175734A1 (en) Cardiac monitors
JPH0510108B2 (en)
CA1103315A (en) Apparatus for detecting arrhythmias
CA1138531A (en) Cardiac arrhythmia detector and recorder
US3921624A (en) Apparatus for recording heart rate rhythm
EP1191973B1 (en) Medical implant

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB LI LU NL SE

17P Request for examination filed

Effective date: 19860210

17Q First examination report despatched

Effective date: 19870724

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

RIN1 Information on inventor provided before grant (corrected)

Inventor name: SPENCER, MARIACARDIAC RECORDERS LIMITED