HEART RATE MONITOR

• US 3,608,545 A
• Filed: 11/25/1968
• Issued: 09/28/1971
• Est. Priority Date: 11/25/1968
• Status: Expired due to Term

• Current Assignee: Bernard Novack, Jesse L. Acker
• Original Assignee: Bernard Novack, Jesse L. Acker
• Inventors: Novack, Bernard, Acker, Jesse L.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US04/778,382
• Time in Patent Office: 1,037 Days
• Field of Search: 128/2.5P,2.5S,2.5T,2.06,2.5M
• US Class Current: 600/513
• CPC Class Codes: A61B 5/02455 provided with high/low alarm devices
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/361 Detecting fibrillation

Abstract

In a heart rate monitor, two electrical inputs derived from ECG. electrodes and from an arterial pulse pickup are received by separate channels to produce respective electrical outputs, such as, variable DC voltages, corresponding to the intervals between successive QRS and arterial pulses, and hence to the rates of such pulses, deviations of such electrical outputs beyond adjustably preset limits of allowable ranges therefor are detected, and an alarm is actuated, as through a digital logic circuit and preferably to operate in synchronism with the QRS pulses, only in response to patient conditions represented by predetermined combinations of detected deviations of the electrical outputs outside the allowable ranges therefor. Further, suitable time delays are provided to cause actuation of the alarm soon after the occurrence of certain combinations of deviations, such as, no pulse and no ECG. or fibrillation (high ECG. rate and no pulse) and to delay the actuation of the alarm in the case of other deviations, such as, the combination of high ECG. or QRS and high arterial pulse rates.

Claims

1. Apparatus for monitoring the heart rate of a patient comprising means including transducer means attachable to the patient to provide first and second electrical outputs characteristic of the rates of QRS and arterial pulses, respectively, alarm means actuable to signal cardiac arrythmias, means to detect deviations of said first and second electrical outputs beyond upper and lower limits of allowable ranges therefor, and means for causing actuation of said alarm means only in response to patient conditions represented by predetermined combinations of detected deviations of said first and second electrical outputs from said allowable ranges.

2. Apparatus as in claim 1, in which said means for causing actuation of the alarm means includes time delay means providing different time delays for said actuation of the alarm means upon occurrences of certain of said predetermined combinations of detected deviations and of others of said predetermined combinations of detected deviations.

3. Apparatus as in claim 1, in which said means for causing actuation of the alarm means includes means to produce respective signals upon occurrences of said predetermined combinations of detected deviations, and alarm-actuating means operable upon the accumulation of predetermined numbers of said signals.

4. Apparatus as in claim 3, in which said predetermined number of signals corresponding to certain of said combinations of detected deviations is different from said predetermined number of signals corresponding to others of said combinations of detected deviations, whereby to provide different time delays for actuation of said alarm means in response to the occurrences of different combinations of detected deviations.

5. Apparatus as in claim 3, further comprising timed means to reset said alarm-actuating means at predetermined intervals so that said alarm means is actuated thereby upon the accumulation of said predetermined numbers of signals within any of said intervals.

6. Apparatus as in claim 5, in which said predetermined number of signals corresponding to certain of said combinations of detected deviations is different from said predetermined number of signals corresponding to others of said combinations of detected deviations, whereby to provide different time delays for actuation of said alarm means in response to the occurrences of different combinations of detected deviations.

7. Apparatus as in claim 1, further comprising means to operate said alarm means in synchronism with said QRS pulses upon said actuation of the alarm means.

8. Apparatus as in claim 1, in which said predetermined combinations of detected dEviations represent a first condition in which QRS and arterial pulse rates are both above said upper limits of said allowable ranges therefor, a second condition in which QRS and arterial pulse rates are both below said lower limits of said allowable ranges therefor, a third condition in which said QRS pulse rate is above said upper limit of said allowable range therefor and there is no arterial pulse, and a fourth condition in which there is not QRS pulse and no arterial pulse.

9. Apparatus as in claim 8, in which said means for causing actuation of the alarm means includes means to produce first and second signals upon each occurrence of said first condition and upon each occurrence of any of said second, third and fourth conditions, respectively, and alarm-actuating means operable upon the accumulation of a relatively large number of said first signals and a relatively small number of said second signals.

10. Apparatus as in claim 9, further comprising timed means to reset said alarm-actuating means at predetermined intervals so that said alarm means is actuated thereby upon the accumulation of said large number of first signals or said small number of second signals within any of said intervals.

11. Apparatus as in claim 1, in which said means to provide said first and second electrical outputs has separate channels extending from the respective transducer means and each including amplifier means with automatic gain control to provide output pulses of constant amplitude irrespective of the amplitude of the pulses from the respective transducer means, and means to produce a DC voltage of a magnitude that varies in accordance with the lengths of successive intervals between said output pulses of constant magnitude and which constitutes said electrical output from the respective channel.

12. Apparatus as in claim 1, in which said means to provide said first and second electrical outputs has separate channels extending from the respective transducer means and each including means to produce a DC voltage of a magnitude that varies in accordance with the lengths of successive intervals between pulses from the respective transducer means to constitute said electrical output of the respective channel, and said means to detect deviations of said first and second electrical outputs includes means to produce standard DC voltages of magnitudes representing said upper and lower limits of the allowable ranges and comparator circuit means for issuing corresponding signals when the DC voltages of variable magnitude constituting said first and second electrical outputs are outside the ranges of voltages established by said standard DC voltages.

13. Apparatus as in claim 12, in which said means to produce said standard DC voltages include, for each standard voltage, amplifier means having a fixed input voltage and a feedback loop with a potentiometer having a resistance value that is variable by movement of the arm of said potentiometer so that the standard DC voltage at the output of said amplifier means is adjusted inversely with respect to said movement of the arm.

14. Apparatus as in claim 12, in which said means for causing actuation of said alarm means includes digital logic circuit means receiving said signals from said comparator circuit means and producing signals for causing actuation of the alarm means only when the received signals correspond to said predetermined combinations of deviations.

15. Apparatus as in claim 14, in which each of said separate channels further includes means to transmit a signal directly to said logic circuit means upon the absence of pulses from the respective transducer means.

16. Apparatus as in claim 1, further comprising signal lights for visually indicating the patient'"'"''"'"'s QRS and arterial pulses, and means operable by the respective transducer means to effect illumination of said signal lights in synchronism with said QRS and arterial pulses.

17. Apparatus as in claim 1, in which said transduCer means includes ECG electrodes for producing electrical pulses corresponding to said QRS and a photoplethysmograph pickup for producing electrical pulses corresponding to said arterial pulse, and variable power supply means are provided for said photoplethysmograph pickup to ensure that the output from the latter is unaffected by variations of said pickup and of the patient'"'"''"'"'s skin transmissibility.