US3552386A — Arrhythmia detecting apparatus and method

Claim 1

Independent Claim 181 words

An arrhythmia detecting system for operation on electrocardiographic (ECG.) signals normally including P, Q, R, S and T wave portions, said system comprising: signal-selecting means responsive to said ECG. signals for producing a pulse output when the derivative of a portion of said ECG. signal attains a predetermined threshold value for a certain minimum time interval and does not fall below said threshold value for more than a certain maximum time interval; circuit means operative during a first and a subsequent operating period and responsive to said derivative pulse output for producing first and second outputs respectively, each of said first and second outputs being indicative of the time during which said derivative pulse output is present during the corresponding one of said operating periods; storage means for storing said first output produced during said first operating period; and output means operatively coupled to said storage means and said circuit means for producing an output indication when the second output produced during said subsequent operating period attains a predetermined relationship to the stored first output produced during said first operating period.

Claim 2

Dependent Claim 181 words

An arrhythmia detecting system for operation on electrocardiographic (ECG.) signals normally including P, Q, R, S and T wave portions, said system comprising: signal-selecting means responsive to said ECG. signals for producing a pulse output when the derivative of a portion of said ECG. signal attains a predetermined threshold value for a certain minimum time interval and does not fall below said threshold value for more than a certain maximum time interval; circuit means operative during a first and a subsequent operating period and responsive to said derivative pulse output for producing first and second outputs respectively, each of said first and second outputs being indicative of the time during which said derivative pulse output is present during the corresponding one of said operating periods; storage means for storing said first output produced during said first operating period; and output means operatively coupled to said storage means and said circuit means for producing an output indication when the second output produced during said subsequent operating period attains a predetermined relationship to the stored first output produced during said first operating period.

Claim 3

Dependent Claim 180 words

The arrhythmia detecting system of claim 1, said signal-selecting means including: means for producing the derivative of a received ECG. signal; means for attenuating said derivative to preselected values; means for indicating when the attenuated derivative of the QRS portion of said ECG. signal exceeds said predetermined threshold value; pulse stretching means responsive to said indicating means for producing said derivative pulse output when said attenuated derivative exceeds said threshold value for said minimum time interval and does not fall below threshold value for more than said maximum time interval; said first output produced by said circuit means being representative of the period of the QRS portion of the ECG. signal; and said output means including means for comparing the width of the QRS portion of the ECG. signal represented by said first output during said first operating period with the width of the QRS portion of the ECG. signal represented by said second output during said subsequent operating period, said comparing means being operable to produce said output indication in response to abnormal QRS portions of the ECG. signal.

Claim 4

Dependent Claim 76 words

The system of claim 2, said pulse stretching means including: first delay means responsive to said indicating means for producing a signal each time said attenuated derivative exceeds said threshold value for said minimum time interval; second delay means for producing a signal as long as successive signals from said first delay means occur within said maximum time interval; and means responsive to the signal from said second delay means for producing said derivative pulse output.

Claim 5

Dependent Claim 46 words

The system as in claim 2 further including means responsive to a selected plural number of occurrences of said output indications during said subsequent operating period for producing an output signal indicative of the occurrence of a plurality of abnormal QRS portions of received ECG. signals.

Claim 6

Dependent Claim 60 words

The system as in claim 4 further including: means responsive to a plural number of occurrences of abnormal QRS portions for producing an output signal related to the frequency of abnormal QRS portions; and means responsive to a plural number of occurrences of abnormal QRS portions for producing an output signal related to the number of sequential abnormal QRS portions.

Claim 7

Dependent Claim 57 words

The system as in claim 1, said circuit means further including: an oscillator for producing pulses at preselected intervals in response to the application of said derivative pulse output thereto; and an accumulator connected to receive said oscillator pulses for producing said first output indicative of the time said derivative pulse output is applied to said oscillator.

Claim 8

Dependent Claim 43 words

The system as in claim 6, said accumulator being a counter adapted to count pulses from said oscillator; and said storage means including a storage register which is operative to store the count of pulses by said counter during said first operating period.

Claim 9

Dependent Claim 72 words

The system as in claim 7 wherein said output means includes gating means for transferring into said counter the complement of the count of pulses stored in said storage register to preset said counter to the complement of said count of pulses for producing an overflow signal when the number of pulses applied to said counter during said subsequent operating period exceeds the stored count of pulses during said first operating period.

Claim 10

Dependent Claim 48 words

The system as in claim 2, said attenuating means including: a variable attenuator; and means for adjusting said variable attenuator during said first operating period in response to the amplitude of the largesT derivative of the ECG. signal applied to said signal-selecting means during said first operating period.

Claim 11

Dependent Claim 89 words

The system as in claim 1, said signal-selecting means including: a signal filter having a band-pass frequency characteristic centered at approximately 25 hertz; a variable attenuator for receiving the ECG. signals; means for adjusting said variable attenuator in response to the amplitude of the derivative of the largest signal passed by said signal filter during said first operating period; and means coupled to the output of said variable attenuator for producing said derivative pulse output in response to signals passed by said variable attenuator during said subsequent operating period.

Claim 12

Independent Claim 121 words

The method of analyzing electrocardiographic signals normally including P, Q, R, S and T wave portions comprising the steps of: normalizing to a predetermined value the derivative of a selected portion of the ECG. signals received during a first operating period; measuring the time during which the derivative of the normalized ECG. signal exceeds said predetermined value and also meets predetermined time duration requirements during the first operating period; storing said measurement of time; measuring the time during which the derivative of the normalized ECG. signals received during a subsequent operating period exceeds said predetermined value; and comparing said measurements during said first and subsequent operating periods to produce an output indication in response to said measurements attaining a preselected relationship.

Claim 13

Independent Claim 121 words

The method of analyzing electrocardiographic signals normally including P, Q, R, S and T wave portions comprising the steps of: normalizing to a predetermined value the derivative of a selected portion of the ECG. signals received during a first operating period; measuring the time during which the derivative of the normalized ECG. signal exceeds said predetermined value and also meets predetermined time duration requirements during the first operating period; storing said measurement of time; measuring the time during which the derivative of the normalized ECG. signals received during a subsequent operating period exceeds said predetermined value; and comparing said measurements during said first and subsequent operating periods to produce an output indication in response to said measurements attaining a preselected relationship.

Claim 14

Dependent Claim 83 words

The method as in claim 11 wherein: the step of normalizing includes altering the amplitude of the derivative of received ECG. signals to preselected values; and the measuring step during each of said first and subsequent operating periods includes measuring the width of the normalized derivative of the QRS portion of the ECG. signals which exceed a predetermined threshold for a predetermined minimum period of time and which do not fall below said threshold for more than a predetermined maximum period of time.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-01-04	1974-07-06	1975-01-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-01-04	1978-07-06	1979-01-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-01-04	1982-07-06	1983-01-05	$7700.00	Window Closed / Lapsed

Arrhythmia detecting apparatus and method

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