Apparatus and method for determining onset times of pulses and use thereof in computing interarterial blood pressure electromechanical interval

• US 4,023,563 A
• Filed: 09/22/1975
• Issued: 05/17/1977
• Est. Priority Date: 09/22/1975
• Status: Expired due to Term

• Current Assignee: American Home Products Corporation (Pfizer Inc.)
• Original Assignee: American Home Products Corporation (Pfizer Inc.)
• Inventors: Mentelos, Richard A., Reynolds, Charles A., Lewis, Donald E.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/615,305
• Time in Patent Office: 603 Days
• Field of Search: 128/2.05 A, 128/2.05 D, 128/2.05 F, 128/2.05 M, 128/2.05 P, 128/2.05 Q, 128/2.05 R, 128/2.06 R, 73/194 E, 307/235 A, 307/235 J, 324/188, 328/114, 328/162
• US Class Current: 600/485
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: H03K 5/153 Arrangements in which a pulse is delivered at the instant when a predetermined characteristic of an input signal is present or at a fixed time interval after this instant switching at zero crossing H03K17/13

Abstract

Apparatus and a method for determining the onset of an interarterial blood pressure pulse and measuring the time delay preceding the onset from the corresponding electrical heartbeart triggering signal wherein the blood pressure pulse is converted to an electrical input signal which is split into two identical components, one being delayed in time, inverted and amplified after which it is added to the other. A timer measures the duration between the electrical heartbeat actuating signal and the point at which the sum of the blood pressure component signals reaches a peak and subtracts from that result the time delay applied to the one component to yield the electromechanical interval between the electrical heartbeat signal and onset of the blood pressure pulse.

Claims

1. Apparatus for determining the time of onset of an electrical pulse measured from a reference time comprising:

means for producing from each said electrical pulse an identical corresponding respective pulse;

means for shifting the phase of said corresponding pulse with respect to said electrical pulse by a predetermined time;

means for inverting and amplifying said phase shifted corresponding pulse;

3. Apparatus according to claim 1 wherein said predetermined characteristic is the peak of said combined pulse.

4. Apparatus according to claim 1 wherein said predetermined characteristic is the point of change in voltage polarity of said combined pulse.

6. Apparatus according to claim 4 wherein said actuating means comprises means for detecting the occurrence of an event, said timing means being actuated in response to said event for measuring said onset time from said event.

7. Apparatus according to claim 4 wherein said predetermined characteristic is the peak of said summation pulse.

8. Apparatus according to claim 6 further comprising means responsive to said summation pulse peak detecting means for resetting said timing means for a new measurement.

9. Apparatus according to claim 4 wherein said predetermined characteristic is the point of change in voltage polarity of said summation pulse.

11. A method according to claim 9 wherein said predetermined characteristic is the peak of said summation pulse.

12. A method according to claim 9 wherein said predetermined characteristic is the point of change in voltage polarity of said summation pulse.

14. Apparatus according to claim 12 wherein said predetermined characteristic is the point of change in voltage polarity of said summation pulse.

15. Apparatus according to claim 12 wherein said predetermined characteristic is the peak of said summation pulse.

2. means for combining said electrical pulse with said corresponding amplified, inverted and phase shifted respective pulse to form a combined pulse;

timer actuating means operative at said reference time;

a timer responsive to said actuating means and to a predetermined characteristic of said combined pulse for producing a first signal having a characteristic with a magnitude related to the time of occurrence of said combined pulse characteristic measured from said reference time;

means for producing a second signal having a characteristic with a magnitude related to said predetermined phase shift time; and

means for combining said first and second signals to form a third signal having a characteristic with a magnitude related to the difference in magnitudes of said respective characteristics of said first and second signals, said third signal characteristic magnitude being related to said onset time.

5. Apparatus for determining the time of onset of an electrical pulse comprising:

means for splitting said electrical pulse into respective first and second pulses with waveforms identical to that of said electrical pulse;

means for delaying said first pulse for a constant time period;

means for inverting and amplifying said delayed first pulse;

means for adding said delayed inverted and amplified first pulse and said second pulse to form a summation pulse;

means for detecting a predetermined characteristic of said summation pulse;

timing means responsive to said detection means for indicating the time at which said predetermined characteristic occurs,

means for actuating said timing means; and

means for subtracting said constant time period from said predetermined characteristic occurrence time, the output of said subtracting means being proportional to the time of onset of said pulses.

10. A method of determining the time of onset of electrical pulses having varying amplitudes and slopes relative to a reference time comprising:

actuating a timer to measure the time elapsed from said reference time;

splitting each of said electrical pulses into respective first and second identical pulses;

delaying said first pulse for a constant time period;

amplifying and inverting said delayed first pulse;

adding said amplified and inverted first pulse to said second pulse to form a summation pulse;

detecting the occurrence of a predetermined characteristic of said summation pulse;

determining from said timer the time elapsed from said reference time at said occurrence; and

subtracting from said elapsed time at said occurrence said constant time period.

13. In an apparatus for determining the time interval between one electrical pulse indicating a first event and a following electrical pulse indicating a second event having a timer which begins measuring time in response to said one pulse and ceases measuring time upon onset of said following pulse, the improvement which comprises:

means for splitting said following pulse into respective first and second identical pulses,

means for delaying said first pulse for a constant time period,

means for inverting and amplifying said delayed first pulse,

means for summing said delayed inverted and amplified first pulse and said second pulse to form a summation pulse,

means for detecting a predetermined characteristic of said summation pulse,

means responsive to said detecting means for storing the measurement in said timer, and

means for subtracting from the measurement in said storing means, said constant time period.

16. Apparatus for determining the electromechanical time interval between the myocardial electrical impulse transmitted to the heart of a subject and the onset of the absolute blood pressure pulse resulting from the heartbeat induced by the myocardial impulse comprising:

means for producing an electrical waveform symmetrical to the waveform of said absolute blood pressure pulse,

means for producing from said electrical waveform first and second signals having identical waveforms symmetrical thereto,

means for shifting the phase of said first signal by a predetermined time,

means for inverting and amplifying said phase shifted signal to form a third signal,

means for combining said second and third signals to form a fourth signal,

timing means for detecting the time of occurrence of a predetermined characteristic of said fourth signal, said timing means including actuating means responsive to said myocardial electrical impulse to measure time therefrom and produce a fifth signal having a characteristic with a magnitude related to the time from said myocardial impulse to said time of occurrence,

means for producing a sixth signal with a characteristic having a magnitude related to said phase shift time, and

means for combining said fifth and sixth signals to form a seventh signal having a characteristic with a magnitude related to the difference in magnitudes of said respective characteristics of said fifth and sixth signals, said seventh signal characteristic magnitude being related to said electromechanical interval.

18. Apparatus according to claim 16 further comprising means responsive to said myocardial electrical impulse for resetting the measurement in said timing means to zero.

17. Apparatus for determining the electromechanical time interval between the myocardial electrical impulse transmitted to the heart of a subject and the onset of an electrical signal waveform representative of the absolute blood pressure pulse resulting from the heartbeat induced by the myocardial impulse comprising:

means for producing from said electrical signal first and second signals identical thereto,

means for delaying said first signal by a predetermined amount of time to yield a delayed signal,

means for inverting and amplifying said delayed signal,

means for adding said inverted and amplified delayed signal to said second signal to form a resultant signal,

means for detecting the peak of said resultant signal,

timing means for measuring elapsed time, said timing means being responsive to said myocardial electrical impulse for beginning said measurement and responsive to said peak detecting means for terminating said measurement, and

means for subtracting from said terminated count said predetermined amount of time.