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System for detecting heart pacemaker pulses

  • US 4,226,245 A
  • Filed: 11/06/1978
  • Issued: 10/07/1980
  • Est. Priority Date: 11/06/1978
  • Status: Expired due to Term
First Claim
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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:

  • 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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