Continuity detector for heartbeat rate measuring system

Claim 2

Apparatus for monitoring a succession of heartbeats and estimating heart rate, comprising: first and second electrodes adapted to contact a patient and transmit an EKG signal indicative of heartbeat activity; heart rate means, connected to the first and second electrodes, for monitoring the EKG signal and estimating heart rate; means for coupling a prescribed continuity signal to the first electrode, for transmission through the patient to the second electrode; means for detecting the presence of the continuity signal at the second electrode and producing an inhibit signal whenever the continuity signal is not detected; and means for inhibiting the heart rate means in response to the inhibit signal.

Claim 3

Apparatus as defined in claim 1, wherein the detection means includes: means for determining the difference between the amplitude of the continuity signal present at the first electrode and the amplitude of the continuity signal present at the second electrode and for producing a corresponding amplitude signal; and means for comparing the amplitude signal to a prescribed threshold and for producing the inhibit signal whenever the threshold is exceeded.

Claim 4

Apparatus as defined in claim 1, wherein the continuity signal is an ac signal.

Claim 5

Apparatus as defined in claim 3, wherein the frequency spectrum of the continuity signal is distinct from that of the EKG signal.

Claim 6

Apparatus as defined in claim 1, wherein: the heart rate means includes means for measuring the time intervals between successive heartbeats, and means for estimating heartbeat rate based on a plurality of such time interval measurements; and the means for inhibiting inhibits the means for measuring if the inhibit signal occurs at any time between successive heartbeats.

Claim 7

Apparatus as defined in claim 1, and further including: counter means for accumulating a measurement of the amount of time the inhibit signal occurs; and threshold detector means for inhibiting the heart rate means from monitoring the EKG signal if the measurement exceeds a prescribed threshold.

Claim 8

Apparatus as defined in claim 6, wherein the counter means increments the measurement when the inhibit signal is present and decrements the measurement when the inhibit signal is not present.

Claim 9

Apparatus for estimating heartbeat rate, comprising: first and second electrodes adapted to contact a patient at spaced locations and transmit an EKG signal indicative of heartbeat activity; heart rate means connected to the first and second electrodes, for detecting the successive heartbeats of the EKG signal, and for measuring the time intervals therebetween and estimating heartbeat rate based on those measurements; continuity detection means for detecting electrical continuity from one electrode through the patient to the other electrode, the continuity detection means including means for coupling a prescribed continuity signal to the first electrode, for transmission through the patient to the second electrode, and means for detecting the presence of the continuity signal at the second electrode and producing an inhibit signal whenever the continuity signal is not detected; and inhibit means for inhibiting the heart rate means from measuring the current heartbeat interval, whenever the inhibit signal is present and at least until the heart rate means detects the first heartbeat after the inhibit signal terminates, whereby erroneous heartbeat estimates caused by a lack of continuity between the first and second electrodes are prevented.

Claim 10

Apparatus for estimating heartbeat rate, comprising: first and second electrodes adapted to contact a patient at spaced locations and transmit an EKG signal indicative of heartbeat activity; heart rate means connected to the first and second electrodes, for detecting the successive heartbeats of the EKG signal, and for measuring the time intervals therebetween and estimating heartbeat rate based on those measurements; continuity detection means for detecting electrical continuity from one electrode through the patient to the other electrode, the continuity detection means including means for coupling a prescribed continuity signal to the first electrode, for transmission through the patient to the second electrode, and means for detecting the presence of the continuity signal at the second electrode and producing an inhibit signal whenever the continuity signal is not detected; and inhibit means for inhibiting the heart rate means from measuring the current heartbeat interval, whenever the inhibit signal is present and at least until the heart rate means detects the first heartbeat after the inhibit signal terminates, whereby erroneous heartbeat estimates caused by a lack of continuity between the first and second electrodes are prevented.

Claim 11

Apparatus as defined in claim 8, wherein the means for detecting includes: means for determining the difference between the amplitude of the continuity signal present at the first electrode and the amplitude of the continuity signal present at the second electrode and for producing a corresponding amplitude signal; and means for comparing the amplitude signal to a prescribed threshold and for producing the inhibit signal whenever the threshold is exceeded.

Claim 12

Apparatus as defined in claim 8, wherein the continuity signal is an ac signal having a frequency spectrum distinct from that of the EKG signal.

Claim 13

Apparatus as defined in claim 8, and further including: up/down counter means for accumulating a measurement of the amount of time the inhibit signal is present in excess of the amount of time the inhibit signal is not present; and threshold detector means for inhibiting the heart rate means from estimating heartbeat rate if the up/down counter means measurement ever exceeds a prescribed threshold.

Claim 14

Apparatus for estimating heartbeat rate, comprising: first and second electrodes adapted to contact a patient at spaced locations and transmit an EKG signal indicative of heartbeat activity; heart rate means, connected to the first and second electrodes, for detecting the successive heartbeats of the EKG signal, measuring the time intervals therebetween, and estimating heartbeat rate based on those measurement; continuity detection means for detecting electrical continuity from one electrode through the patient to the other electrode, the continuity detection means including means for coupling a prescribed ac continuity signal to the first electrode, for transmission through the patient to the second electrode, the continuity signal having a frequency spectrum distinct from that of the EKG signal, means for determining the difference between the amplitude of the continuity signal present at the first electrode and the amplitude of the continuity signal present at the second electrode and for producing a corresponding amplitude signal, and p1 means for comparing the amplitude signal to a prescribed threshold and for producing an inhibit signal whenever the threshold is exceeded; inhibit means for inhibiting the heart rate means from measuring the current heartbeat interval whenever the inhibit signal is present and at least until the heart rate means detects the first heartbeat after the inhibit signal terminates, whereby erroneous heartbeat estimates caused by a lack of continuity between the first and second electrodes are prevented; up/down counter means for accumulating a measurement of the amount of time the inhibit signal is present in excess of the amount of time the inhibit signal is present in excess of the amount of time the inhibit signal is not present; and threshold detector means for inhibiting the heart rate means from estimating heartbeat rate if the up/down counter means measurement ever exceeds a prescribed threshold.

Claim 15

Apparatus for estimating heartbeat rate, comprising: first and second electrodes adapted to contact a patient at spaced locations and transmit an EKG signal indicative of heartbeat activity; heart rate means, connected to the first and second electrodes, for detecting the successive heartbeats of the EKG signal, measuring the time intervals therebetween, and estimating heartbeat rate based on those measurement; continuity detection means for detecting electrical continuity from one electrode through the patient to the other electrode, the continuity detection means including means for coupling a prescribed ac continuity signal to the first electrode, for transmission through the patient to the second electrode, the continuity signal having a frequency spectrum distinct from that of the EKG signal, means for determining the difference between the amplitude of the continuity signal present at the first electrode and the amplitude of the continuity signal present at the second electrode and for producing a corresponding amplitude signal, and p1 means for comparing the amplitude signal to a prescribed threshold and for producing an inhibit signal whenever the threshold is exceeded; inhibit means for inhibiting the heart rate means from measuring the current heartbeat interval whenever the inhibit signal is present and at least until the heart rate means detects the first heartbeat after the inhibit signal terminates, whereby erroneous heartbeat estimates caused by a lack of continuity between the first and second electrodes are prevented; up/down counter means for accumulating a measurement of the amount of time the inhibit signal is present in excess of the amount of time the inhibit signal is present in excess of the amount of time the inhibit signal is not present; and threshold detector means for inhibiting the heart rate means from estimating heartbeat rate if the up/down counter means measurement ever exceeds a prescribed threshold.

Claim 18

A method as defined in claim 13, wherein the step of detecting the presence of the continuity signal includes steps of: detecting the difference between the amplitude of the continuity signal at the first electrode and the amplitude of the continuity signal at the second electrode and producing a corresponding amplitude signal; and comparing the amplitude signal to a prescribed threshold and producing the inhibit signal whenever the threshold is exceeded.

Claim 19

A method as defined in claim 13, wherein the continuity signal is an ac signal having a frequency spectrum distinct from that of the EKG signal.

Claim 20

A method as defined in claim 13, wherein: the step of monitoring and estimating includes steps of measuring the time intervals between successive heartbeats, and estimating heartbeat rate based on a plurality of such time interval measurements; and the step of inhibiting inhibits the step of measuring if the inhibit signal occurs at any time between successive heartbeats.

Claim 21

A method as defined in claim 13, and further including steps of: accumulating a measurement of the amount of time the inhibit signal occurs; and inhibiting the step of monitoring if the measurement exceeds a prescribed threshold.

Claim 22

A method as defined in claim 17, wherein the step of accumulating increments the measurement when the inhibit signal is present and decrements the measurement when the inhibit signal is not present.