Method of arrhythmia detection with detecting mechanism

• US 4,356,827 A
• Filed: 09/16/1980
• Issued: 11/02/1982
• Est. Priority Date: 11/27/1978
• Status: Expired due to Term

• Current Assignee: Colin Electronics Co., Ltd.
• Original Assignee: Nippon Collin Co., Ltd.
• Inventors: Harada, Chikao, Uemura, Masahiro, Sakurado, Kenichi, Kakamu, Tsunehito
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Jaworski, Francis J.
• Application Number:
  US06/187,723
• Time in Patent Office: 777 Days
• Field of Search: 128/680-683, 128/702-703, 128/705
• US Class Current: 600/493
• CPC Class Codes: A61B 5/02208 using the Korotkoff method
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence

Abstract

A method of using a sphygmomanometer having a built-in arrhythmia detecting mechanism, wherein the blood pressure measuring portion contains a pulsation detector, which receives pulse sounds including Korotkoff sounds for electrically converting the pulse sounds into wave form signals of the vascular pulse wave and output the same, and a mechanism indicating the blood pressure value by means of detecting the Korotkoff sounds recognized and separated from the wave form signals of the vascular pulse wave output in the above-mentioned way; the incorporated arrhythmia detecting mechanism receives the wave form signals of the vascular pulse wave for comparing the cycle of the wave form signals with a predetermined criterion in order to electrically detect irregularities, if any, in the signals for detecting the existence of arrhythmias. This sphygmomanometer is capable of measuring the blood pressure simultaneously with the detecting of arrhythmia.

Claims

1. A method of arrhythmia detection using a sphygomanometer with an arrhythmia detecting mechanism, wherein diagnosis of arrhythmia is done simultaneously with the blood pressure measurement, comprising the steps of detecting arrythmia by comparing the ratio of two consecutive physiological pulse interval times with a predetermined allowable range value, determining an arrythmia if said ratio value is out of said allowable range, setting said two consecutive pulse interval times as one duration time T₁ from a base point of a said pulse appearing or disappearing to the next similar base point of a said pulse appearing or disappearing, taking a succeeding duration of time T₂ in the identical way between each two similar base points, said arrhythmia detecting method being characterized by the steps of simultaneous derivation of arrythmia system input from the Korotkoff or physiological pulse pressure waveforms of the sphygmomanometric portion of the system, electrically forming a first pulse from said physiological pulse detecting;

calculating two time values (T₁ -t₁) and (T₂ -t₁) by deducting from one pulse interval T₁ and the next pulse interval T₂ respectively the pulse interval t₁ of said first pulse, said time values being made the objects of the pulse interval comparison;

completing said comparison within the pulse duration time of a second pulse triggered at every second rising of said first pulse width t₁, and clearing the memory of pulse interval comparison within the time duration (t₁ -t₂), i.e., from the rising of said second pulse to the falling of said first pulse.

2. A method as claimed in claim 1, and the steps of indicating blood pressure values by using logic circuitry for recognizing the Korotkoff sounds and an indicating means for indicating blood pressure values in response to the output from said logic circuitry.

3. A method as claimed in claim 2, and the step of digitally indicating blood pressure values by using light emitting diodes (LEDs).

4. A method as claimed in claim 1, wherein said arrhythmia detecting steps further comprise:

converting a pulse interval, which spans the time from the appearance point or the disappearance point of a pulse to the appearance point or the disappearance point of the next pulse, that is, from one base point to the next base point in the same phase, into another physical amount corresponding to said pulse interval;

comparing said converted physical amount with a predetermined criterion using a window comparator in order to check whether said physical amount is within said limit of allowance; and

indicating arrhythmia by using the output of said window comparator to deive an indicating means.

5. A method as claimed in claim 4, wherein said arrhythmia detecting steps further comprise:

forming a pulse with a rectangular wave with the pulse width t₁ in response to signals from a pulse to be detected using a first pulse forming circuit;

memorizing the converted physical amount from said converting circuit using a memory circuit;

a timing circuit causing a least said converting circuit and said memory circuit to function in an orderly manner and without error by using a timing circuit;

calculating the physical amount, which corresponds to the deducted value, respectively from said one pulse interval T₁ and the next pulse interval T₂ minus said pulse width t₁, as the objects of pulse interval comparison by using an operation circuit;

forming said pulse with a pulse width t₂, which is shorter than the pulse width t₁, capable of finishing said comparison of pulse interval within the duration of time t₂, a second pulse forming circuit and clearing said memory circuit within the duration of time rest (t₁ -t₂); and

using the output of said first pulse forming circuit as the input to a flip-flop circuit which in turn outputs to said second pulse forming circuit and said timing circuit.

6. A method as claimed in claim 5, wherein said converting circuit converts the time (T₁ -t₁) from the first pulse to the second pulse in the pulse signal which is output in the first pulse forming circuit and synchronized with the pulse seconds to be detected into a voltage;

said operation circuit receives the converted voltage value through said memory circuit and computes and produces a voltage increased in amount and another voltage decreased in amount respectively by a certain predetermined percentage for inputting both voltage values to said window comparator as the upper and lower limits, and said indicating means indicating the existence of arrythmia when the voltage value of the time (T₂ -t₁) ranging from the second pulse to the third pulse, which is input directly from said converting circuit to said window comparator, is out of the range between said upper limit and lower limit.

7. A method as claimed in claim 6, wherein said second pulse forming circuit produces a rectangular wave with a pulse width t₂ at every second pulse out of the pulses output from said first pulse forming circuit, and wherein an AND circuit is disposed for receiving said rectangular wave signals and those from said window comparator and delivers signals to said arrhythmia indicating means only when said both signals are input to said AND circuit at the same time.

8. A method as claimed in claim 5, wherein said converting circuit converts the time (T₁ -t₁) from the first pulse to the second pulse, and the time (T₂ -t₁), from the second pulse to the third pulse, of the pulse signal which is output in the first pulse forming circuit and synchronized with the pulse sounds to be detected, into the number of clock pulses, said memory circuit is composed of a pair of circuits for respectively memorizing such two numbers of clock pulses, said operation circuit is a division circuit for determing the ratio of said two clock pulses input through said memory circuit, and said window comparator compares the ratio of said two kinds of clock pulse numbers with the predetermined allowance value, for signalling, when said ratio gets out of the allowable range, said indicating means.

9. A method as claimed in claim 8, wherein said second pulse forming circuit produces a rectangular wave with the pulse width t₂ at every second pulse our of the pulses output from said first pulse forming circuit, and said rectangular wave signal thus produced is input to said division circuit.

10. A method as claimed in any one of claims 5 to 9, wherein the pulse width t₂ of the pulse signal output from said first pulse forming circuit is 7 milliseconds or less.

11. A method as claimed in any one of claims 4 to 9, wherein said indicating means digitally indicates the number of arrythmias using light emitting diodes (LEDs).