Low energy pacing pulse waveform for implantable pacemaker
First Claim
1. In an implantable pulse generator for providing cardiac pacing pulses through a discharge path including implantable pacing electrodes coupled to a patient'"'"'s heart in response to a pacing pulse trigger signal defining a predetermined pacing pulse interval, an improved pacing output circuit for reduced energy expenditure comprising:
- an output capacitor adapted to be charged in a charge path and discharged in said discharge path;
charging circuit means for charging said output capacitor to a predetermined peak voltage level through said charge path; and
discharge circuit means operable in response to said pacing pulse trigger signal for controllably discharging said output capacitor in said discharge path and providing a pacing pulse output voltage across said implantable pacing electrodes commencing at an initial pulse voltage level less than said predetermined peak voltage level and greater than zero and increasing over an initial fraction of said pacing pulse interval to an intermediate pulse voltage level and thereafter exponentially decreasing in voltage amplitude during a remaining fraction of said pulse interval until a terminal end thereof, whereby pacing pulse energy delivered across said pacing electrodes is decreased and a residual charge of said output capacitor at the end of the pacing pulse interval is increased by restraining the discharge of said output capacitor during said initial fraction of said pacing pulse interval.
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Accused Products
Abstract
A tissue electrical stimulator and electrical pulse waveform are described. The stimulator or pulse generator may deliver the pules preferably through an endocardial electrode to pace a heart but could be used for other tissue such as nerves or to deliver defibrillation pulses through other means. A preferred circuit is described employing timing of a gate voltage level on an output transistor for the discharge capacitor(s) of the pulse generator. The waveform has a leading edge starting above zero volts and ramps upward for an initial fraction until a saturation voltage is reached and then ramps downward.
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Citations
25 Claims
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1. In an implantable pulse generator for providing cardiac pacing pulses through a discharge path including implantable pacing electrodes coupled to a patient'"'"'s heart in response to a pacing pulse trigger signal defining a predetermined pacing pulse interval, an improved pacing output circuit for reduced energy expenditure comprising:
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an output capacitor adapted to be charged in a charge path and discharged in said discharge path; charging circuit means for charging said output capacitor to a predetermined peak voltage level through said charge path; and discharge circuit means operable in response to said pacing pulse trigger signal for controllably discharging said output capacitor in said discharge path and providing a pacing pulse output voltage across said implantable pacing electrodes commencing at an initial pulse voltage level less than said predetermined peak voltage level and greater than zero and increasing over an initial fraction of said pacing pulse interval to an intermediate pulse voltage level and thereafter exponentially decreasing in voltage amplitude during a remaining fraction of said pulse interval until a terminal end thereof, whereby pacing pulse energy delivered across said pacing electrodes is decreased and a residual charge of said output capacitor at the end of the pacing pulse interval is increased by restraining the discharge of said output capacitor during said initial fraction of said pacing pulse interval. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In an implantable pulse generator for providing cardiac pacing pulses through a discharge path including an implantable pacing electrode coupled to a patient'"'"'s heart in response to a pacing pulse trigger signal defining a predetermined pacing pulse interval, an improved pacing output circuit for reduced energy expenditure comprising:
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output capacitor means adapted to be charged in a charge path and discharged in said discharge path; charging circuit means for charging said output capacitor means to a predetermined peak voltage level through said charge path; an output circuit means having a conduction path in said discharge path coupled to said output capacitor and having a control gate; and discharge voltage control circuit means operable in response to said pulse trigger signal and coupled to said control gate for providing a variable gate voltage to render said conduction path of said output circuit means conductive for controllably discharging said output capacitor means in said discharge path and providing a pacing pulse output voltage across said implantable pacing electrode(s) commencing at an initial pacing pulse voltage level less than said predetermined peak voltage level and greater than zero and increasing over an initial fraction of said pacing pulse interval to an intermediate pacing pulse voltage level and thereafter decreasing exponentially in voltage amplitude during a remaining fraction of said pulse interval until a terminal end thereof, whereby pacing pulse energy delivered across said pacing electrodes is decreased and a residual charge of said output capacitor at the end of the pacing pulse interval is increased by restraining the discharge of said output capacitor during said initial fraction of said pacing pulse interval. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. In an implantable pulse generator for providing cardiac pacing pulses through implantable pacing electrodes to a patient'"'"'s heart and across an electrode-tissue interface and impedance of a discharge path through the patient'"'"'s heart in response to a pacing pulse trigger signal having a predetermined pulse width, an improved pacing output circuit for reducing energy expenditure comprising:
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an output capacitor adapted to be charged in a charge path and discharged in said discharge path to provide said pacing pulse over said pulse width; discharge switch means having a conduction path in a discharge circuit with said output capacitor and said pacing electrodes having an open state for blocking discharge current flow and an variable closed state for allowing variable current flow in dependence on a switch control signal; charge circuit means for charging said output capacitor to a predetermined charge voltage level while said discharge switch means is in said open state; and discharge circuit means operable in response to said pacing pulse trigger signal for providing a variable control signal to said discharge switch means for partially closing said discharge switch means and discharging said output capacitor at a progressively increasing voltage commencing from an initial pacing pulse voltage level less than said predetermined charge voltage level and greater than zero over an initial fraction of said pacing pulse interval until said discharge switch means is fully closed and thereafter allowing exponential discharge of said output capacitor voltage for a remaining fraction of said pacing pulse interval through said discharge switch. - View Dependent Claims (18, 19, 20, 21)
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- 22. In a tissue stimulator having a timing means for timing a pulse interval and pulse generator means for providing a tissue stimulation pulse, the improvement comprising a pulse generator means configured for providing said tissue stimulation pulse such that when provided, said stimulation pulse has a voltage pulse waveform commencing at an initial pulse voltage level greater, in absolute value, than zero and increasing over an initial fraction of said pulse interval to an intermediate pulse voltage level and immediately thereafter exponentially decreasing in voltage amplitude from the intermediate pulse voltage level during a remaining fraction of said pulse interval.
- 24. In an implantable cardiac pacemaker having timing means for timing a pulse interval and pulse generator means for providing a pacing pulse, the improvement in said pulse generator means comprising circuit means for providing as said pacing pulse a voltage pulse waveform commencing at an initial pulse voltage level greater, in absolute value, than zero and increasing over an initial fraction of said pulse interval to an intermediate pulse voltage level and thereafter exponentially decreasing in voltage amplitude during a remaining faction of said pulse interval.
Specification