System for detecting heart pacemaker pulses
First Claim
1. Apparatus for accurately detecting the pulse width of simulating pulses applied by an artificial pacemaker to a patient'"'"'s heart, each of the stimulating pulses comprising a relatively fast rising leading edge followed by an attenuated wave form portion and terminating in a relatively slow falling trailing edge, said apparatus comprising:
- wave shaping amplifier means for receiving and amplifying the stimulating pulses along with low frequency noise signals in accordance with a transfer function such that low frequency component signals are amplified with a relatively low gain and higher frequency component signals are amplified with a relatively high gain whereby said noise signals are substantially discriminated against;
first normally deactuated threshold means responsive to the output of said amplifier means of an amplitude greater than a first predetermined level for providing a first output signal indicative of the occurrence of the trailing edge;
differential amplifier means responsive to the output of said amplifier means and to the stimulating pulses and noise signals, for providing a difference output signal corresponding to the difference between the input signals;
second normally actuated threshold means responsive to the difference output of an amplitude greater than a second predetermined level for providing a second output signal indicative of the occurrence of the leading edge;
said transfer function of said amplifier means and said first predetermined level being selected to provide an accurate indication of the occurrence of the trailing edge without prematurely responding to the attenuated wave form portion of the stimulating pulse; and
means responsive to the second output signal for disabling said second threshold means and for enabling said first threshold means to initiate detection of the trailing edge of the stimulating pulse.
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Abstract
A system is disclosed for accurately providing a signal or signals indicative of the relatively sharp leading edge and the relatively attenuated trailing edge of a pulse and in particular of a pulse applied by a heart pacemaker to a patient'"'"'s heart. The system of this invention functions to distinctly detect each of the relatively fast rising leading edge and the relatively slow rising trailing edge, while preventing a premature detection of the trailing upon the attenuated or drooping portion of the pacing pulse therebetween.
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Citations
11 Claims
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1. Apparatus for accurately detecting the pulse width of simulating pulses applied by an artificial pacemaker to a patient'"'"'s heart, each of the stimulating pulses comprising a relatively fast rising leading edge followed by an attenuated wave form portion and terminating in a relatively slow falling trailing edge, said apparatus comprising:
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wave shaping amplifier means for receiving and amplifying the stimulating pulses along with low frequency noise signals in accordance with a transfer function such that low frequency component signals are amplified with a relatively low gain and higher frequency component signals are amplified with a relatively high gain whereby said noise signals are substantially discriminated against; first normally deactuated threshold means responsive to the output of said amplifier means of an amplitude greater than a first predetermined level for providing a first output signal indicative of the occurrence of the trailing edge; differential amplifier means responsive to the output of said amplifier means and to the stimulating pulses and noise signals, for providing a difference output signal corresponding to the difference between the input signals; second normally actuated threshold means responsive to the difference output of an amplitude greater than a second predetermined level for providing a second output signal indicative of the occurrence of the leading edge; said transfer function of said amplifier means and said first predetermined level being selected to provide an accurate indication of the occurrence of the trailing edge without prematurely responding to the attenuated wave form portion of the stimulating pulse; and means responsive to the second output signal for disabling said second threshold means and for enabling said first threshold means to initiate detection of the trailing edge of the stimulating pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for accurately detecting the relatively sharp leading edge and attenuated trailing edge of stimulating pulses applied by an artifical pacemaker to a patient'"'"'s heart and for transmitting the detected stimulating pulses, combined with cardiac signals of a patient'"'"'s heart, over a limited bandwidth medium to a remote station, said apparatus comprising:
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(a) selectively actuatable modulation means for generating a carrier signal of a frequency suitable to be transmitted over the limited bandwith medium; (b) detection means for accurately detecting the pulse width of stimulating pulses applied by an artificial pacemaker to a patient'"'"'s heart, each of the stimulating pulses comprising a relatively the fast rising leading edge followed by an attenuated wave form portion and terminating in the relatively slow falling trailing edge, said detector means comprising; (1) wave shaping amplifier means for receiving and amplifying the stimulating pulses along with low frequency noise signals in accordance with a transfer function such that low frequency component signals are amplified with a relatively low gain and higher frequency component signals are amplified with a relatively high gain such that said noise signals are substantially discriminated against; (2) first normally deactuated threshold means responsive to the output of said amplifier means of an amplitude greater than a first predetermined level for providing a first output signal indicative of the occurrence of the trailing edge; (3) differential amplifier means responsive to the output of said amplifier means and to the stimulating pulses and noise signals, for providing a difference output signal corresponding to the difference between the input signals; (4) second normally actuated threshold means responsive to the difference output of an amplitude greater than a second predetermined level for providing a second output signal indicative of the occurrence of the leading edge; (5) said transfer function of said amplifier means and said first predetermined level being selected to provide an accurate indication of the occurrence of the trailing edge without prematurely responding to the attenuated wave form portion of the stimulating pulse; and (6) means responsive to the second output signal for disabling said second threshold means and for enabling said first threshold means to initiate detection of the trailing edge of the stimulating pulse; and (c) means responsive to the first and second output signals for providing a pulse like signal having a pulse width expanded with respect to the period between the first and second output signals and applying the pulse like signal to actuate said modulation means to transmit the carrier signal over the limited bandwidth medium for the expanded pulse width.
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11. Apparatus for accurately detecting the pulse width of stimulating pulses applied by an artificial pacemaker to a patient'"'"'s heart, each of the stimulating pulses including a relatively fast rising leading edge, a relatively slow falling trailing edge and an attentuated, sloping portion therebetween, said apparatus comprising:
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(a) first detection means coupled to receive the stimulating pulses along with noise signals for detecting the leading edge of each of the stimulating pulses and for providing a first output indicative of the occurrence thereof; and (b) second detector means actuatable after the detection of the leading edge for detecting the trailing edge of each stimulating pulse and coupled to receive and variably amplify each of the stimulating pulses in accordance with a transfer function such that said second detector means provides a second output signal indicative the occurrence of the trailing edge without prematurely responding to the attenuated, sloping portion to provide a false indication of the occurrence of the trailing edge.
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Specification