Digital cardiac pacemaker with threshold margin check
First Claim
1. An implantable cardiac pacemaker pulse generator having stimulating signal providing means for generating electrical stimulating pulses having a defined pulse energy and rate adapted to be applied to stimulate the heart, and detecting means for receiving a test signal from an external source and providing a threshold safety margin signal, further comprising safety margin means responsive to said threshold safety margin signal for causing said stimulating signal providing means to provide a test series of stimulating pulses at a rate different than the defined rate when said defined rate is lower than said test rate and at said defined rate where said defined rate exceeds said test rate and to provide one of said stimulating signal having a pulse energy reduced by a predetermined amount from the defined pulse energy, and means for terminating said test series when fixed number of said stimulating pulses is produced following the provision of said threshold safety margin signal.
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Accused Products
Abstract
There is disclosed herein a programmable cardiac pacemaker pulse generator utilizing digital circuitry for controlling the provision of cardiac stimulating pulses. The pulse generator is capable of having the rate, the pulse width, the pulse amplitude, the refractory period, the sensitivity and the mode of operation programmed. In addition, the pulse generator can have the output inhibited and can respond to programming signals causing a threshold margin test to be performed, accomplished by threshold safety margin means responsive to a programmed test signal for causing a series of stimulating pulses to be provided a rate different than the previously programmed rate with at least one of the stimulating signals having its energy reduced a predetermined amount. Capture at the reduced energy can be monitored by external equipment.
54 Citations
21 Claims
- 1. An implantable cardiac pacemaker pulse generator having stimulating signal providing means for generating electrical stimulating pulses having a defined pulse energy and rate adapted to be applied to stimulate the heart, and detecting means for receiving a test signal from an external source and providing a threshold safety margin signal, further comprising safety margin means responsive to said threshold safety margin signal for causing said stimulating signal providing means to provide a test series of stimulating pulses at a rate different than the defined rate when said defined rate is lower than said test rate and at said defined rate where said defined rate exceeds said test rate and to provide one of said stimulating signal having a pulse energy reduced by a predetermined amount from the defined pulse energy, and means for terminating said test series when fixed number of said stimulating pulses is produced following the provision of said threshold safety margin signal.
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4. A digitally controlled implantable cardiac pacemaker pulse generator comprising:
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a pair of output terminals at least one of which is adapted to being connected to a lead to which an output signal to stimulate the heart is provided, said output signal being a series of electrical pulses occurring at a defined rate, with each pulse having a defined pulse width; digital control means including clock means, counting means and decoding means, said clock means providing a clock signal to said counting means to be counted, and said decoding means providing said output signal to said output terminals in response to said counting means reaching a certain count; means adapted to respond to an external signal applied to said pulse generator from an external source for providing a test signal; safety margin means responsive to said test signal for providing a safety margin signal to said digital control means; and said digital control means comprising means responding to said safety margin signal for providing a test sequence of a given number of the pulses of said output signal at a test rate above the defined rate when said defined rate is less than said test rate and at said defined rate when said defined rate exceeds said test rate and for decreasing the pulse width of at least one pulse of said given number of pulses; and said safety margin means comprises further means for counting the given number of pulses of said output signal and terminating said test sequence. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification