Cardiac arrhythmia detector

Claim 2

A cardiac arrhythmia detector comprising in combination: a. a set of electrodes adapted to be applied to the body, b. means connected to said electrodes for generating a signal proportional to the first time derivative of the input signal applied to said electrodes, c. means for measuring the peak amplitude of said first time derivative of each waveform due to either normal or abnormal vertricular pumping action, d. means for establishing the running average of the last 10 to 40 of said peak amplitudes, e. means for establishing an amplitude threshold defined as 1/16 to 1/4 of said running average, f. means for measuring the time interval spent above said amplitude threshold by each first time derivative waveform due to either normal or abnormal ventricular pumping action, g. means for establishing the running average of the last 10 to 40 of said time intervals, h. means for comparing each measured peak according to (c) above, to the running average according to (d) above, to identify whether or not the individual peak differs from said running average by more than plus or minus 25 percent, and classifying as normal, on this basis, those for which the difference is less than plus or minus 25 percent, and abnormal those for which the different exceeds plus or minus 25 percent, i. means for comparing each time interval according to (f) above, to the running average according to (g) above, to identify whether or not the individual interval differs from said running average by more than plus or minus 25 percent, and classifying as normal, those for which the difference is less than plus or minus 25 percent, and abnormal those for which the difference exceeds plus or minus 25 percent, j. means for eliminating from consideration, for purposes of establishing the running averages of (d) and (g) above, those derivative waveforms found to be abnormal according to (h) or (i) above, and k. alarm means and means for delivering a positive output to said alarm means whenever a derivative waveform is classified as abnormal according to either (h) or (i) above.

Claim 3

The cardiac arrhythmia detector of claim 1, having in addition thereto a modulator, sounder and touch plate means and means for actuating same from said generated signal whereby a wearer can touch said plate and means whereby said sounder will issue an audible ECG signal which can be sent over a telephone or the like.

Claim 4

The cardiac arrhythmia detector of claim 1, having means inhibiting said alarm until a plurality of abnormal indications are detected within a time period and means for varying said period.

Claim 5

A detector for missing R waves comprising in combination: a. a set of electrodes adapted to be applied to the body, b. circuit means connected to said electrodes, said circuit means including means to identify a missing R wave, including means for measuring the interval between each successive pair of normal R waveforms, and means for declaring a misssing R wave when the current interval is greater than about 1.5 times the immediately previous interval, alarm means and means for actuating said alarm means upon said declaration.

Claim 6

A detector for missing R waves comprising in combination: a. a set of electrodes adapted to be applied to the body, b. circuit means connected to said electrodes, said circuit means including means to identify a missing R wave, including means for measuring the interval between each successive pair of normal R waveforms, and means for declaring a misssing R wave when the current interval is greater than about 1.5 times the immediately previous interval, alarm means and means for actuating said alarm means upon said declaration.

Claim 7

A combined cardiac arrhythmia detector and missing R wave detector comprising in combination: a. a set of electrodes adapted to be applied to the body, b. first circuit means connected to said electrodes, said first circuit means including means whereby the output of the said means is proportional to the first time derivative of the input signal applied to said electrodes, c. means for measuring the peak amplitude achieved by the first time derivative of each waveform due to either normal or abnormal ventricular pumping action, any time said derivative waveform exceeds an amplitude threshold defined as 1/16 1/2 of a running average, d. means for measuring the time interval spent above said amplitude threshold by each first time derivative waveform due to either normal or abnormal ventricular pumping action, e. means for establishing the running average of the last 10 to 40 of said time intervals, f. means for comparing each so measured peak according to said running average to identify whether or not the individual peak differs from said running average by more than plus or minus 25 percent, and classifying as normal, on this basis, those for which the difference is less than plus or minus 25 percent, and abnormal those for which the difference exceeds plus or minus 25 percent, g. means for comparing each said time interval to the said running average to identify whether or not the individual interval differs from said running average by more than plus or minus 25 percent, and classifying as normal, those for which the difference is less than plus or minus 25 percent and abnormal those for which the difference exceeds plus or minus 25 percent, h. means for eliminating from consideration, for purposes of establishing said running averages, those derivative waveforms thus found to be abnormal, i. means for producing a first output signal whenever a derivative waveform is classed as abnormal, j. a second circuit means connected to said electrodes, said means, including means to identify an asynchronous R wave, wherein said means comprises circuitry for measuring the interval between each successive pair of R waveforms,, and means for declaring an asynchronous R wave when the current said interval is greater than about 1.5 times the immediately previous interval, and means for producing a second output signal upon said declaration, and k. alarm means and means for actuating said alarm means by the occurrence of said first output signal followed immediately by said second output signal.

Claim 8

A combined cardiac arrhythmia detector and missing R wave detector comprising in combination: a. a set of electrodes adapted to be applied to the body, b. first circuit means connected to said electrodes, said first circuit means including means whereby the output of the said means is proportional to the first time derivative of the input signal applied to said electrodes, c. means for measuring the peak amplitude achieved by the first time derivative of each waveform due to either normal or abnormal ventricular pumping action, any time said derivative waveform exceeds an amplitude threshold defined as 1/16 1/2 of a running average, d. means for measuring the time interval spent above said amplitude threshold by each first time derivative waveform due to either normal or abnormal ventricular pumping action, e. means for establishing the running average of the last 10 to 40 of said time intervals, f. means for comparing each so measured peak according to said running average to identify whether or not the individual peak differs from said running average by more than plus or minus 25 percent, and classifying as normal, on this basis, those for which the difference is less than plus or minus 25 percent, and abnormal those for which the difference exceeds plus or minus 25 percent, g. means for comparing each said time interval to the said running average to identify whether or not the individual interval differs from said running average by more than plus or minus 25 percent, and classifying as normal, those for which the difference is less than plus or minus 25 percent and abnormal those for which the difference exceeds plus or minus 25 percent, h. means for eliminating from consideration, for purposes of establishing said running averages, those derivative waveforms thus found to be abnormal, i. means for producing a first output signal whenever a derivative waveform is classed as abnormal, j. a second circuit means connected to said electrodes, said means, including means to identify an asynchronous R wave, wherein said means comprises circuitry for measuring the interval between each successive pair of R waveforms,, and means for declaring an asynchronous R wave when the current said interval is greater than about 1.5 times the immediately previous interval, and means for producing a second output signal upon said declaration, and k. alarm means and means for actuating said alarm means by the occurrence of said first output signal followed immediately by said second output signal.

Claim 9

A cardiac R wave detector comprising in combination: a. a set of electrodes adapted to be applied to the body, b. circuit means connected to said electrodes for generating a signal proportional to the first time derivative of the input signal applied to said electrodes, c. said circuit means including means for detecting a first time derivative which is positive in polarity and has a slope on the heart waveform of about 0.02 volts per second and having a time duration of about 50 milliseconds, and means for detecting immediately following said first time derivative, a second first derivative which is negative in polarity, has a slope on the heart waveform of about minus 0.02 volts per second and having a time duration of about 50 milliseconds, and d. means for producing an output signal each time that both criteria are met.

Claim 10

A cardiac R wave detector comprising in combination: a. a set of electrodes adapted to be applied to the body, b. circuit means connected to said electrodes for generating a signal proportional to the first time derivative of the input signal applied to said electrodes, c. said circuit means including means for detecting a first time derivative which is positive in polarity and has a slope on the heart waveform of about 0.02 volts per second and having a time duration of about 50 milliseconds, and means for detecting immediately following said first time derivative, a second first derivative which is negative in polarity, has a slope on the heart waveform of about minus 0.02 volts per second and having a time duration of about 50 milliseconds, and d. means for producing an output signal each time that both criteria are met.

Claim 11

The cardiac R wave detector of claim 6, having a means whereby an alarm is sounded when heartbeats are slower than a normal standard and means for selecting said standard.

Claim 12

The cardiac R wave detector of claim 6, having means associated therewith whereby an alarm is sounded when heartbeats are faster than a normal standard and means for selecting said standard.