Prophylactic pacemaker
First Claim
1. In a demand cardiac pacemaker of the type having input and output means adapted for connection to the heart, the input means including means for sensing natural heartbeats, having pulse generator means connected to said output means and including timing circuit means connected to said sensing means for establishing a first pulse generator means output pulse rate, and having means cooperating with said timing circuit means for providing a second, different pulse generator means output pulse rate, the improvement which comprises means operatively connected to said cooperating means for selectively rendering said first and second rates substantially identical.
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Abstract
A demand pacemaker having different standby and pacing rates and circuitry for selectively rendering the standby and pacing rates substantially identical. First and second capacitors control the standby and pacing rates, respectively, one capacitor being responsive to either a natural heartbeat or a pacemaker output pulse to alter the rate established by the other. In a preferred embodiment, the second capacitor is charged during a pacemaker output pulse and discharges through the first capacitor to decrease its charging time, the charging time of the first capacitor controlling the pacemaker output pulse frequency. Circuitry responsive to externally generated signals causes the second capacitor to charge during both a natural heartbeat or a pacemaker output pulse to render the pacemaker standby and pacing rates substantially identical. In this manner, the pacemaker of the present invention may be employed to monitor heart activity at a first, or standby, rate while providing a pacing function at a second, higher rate, on demand, until such time as the necessity for the pacing function is established with the standby rate then being modified to conform to the pacing rate.
9 Citations
21 Claims
- 1. In a demand cardiac pacemaker of the type having input and output means adapted for connection to the heart, the input means including means for sensing natural heartbeats, having pulse generator means connected to said output means and including timing circuit means connected to said sensing means for establishing a first pulse generator means output pulse rate, and having means cooperating with said timing circuit means for providing a second, different pulse generator means output pulse rate, the improvement which comprises means operatively connected to said cooperating means for selectively rendering said first and second rates substantially identical.
- 4. In a demand cardiac pacemaker of the type having input and output means adapted for connection to the heart, the input means including means for sensing natural heartbeats, having pulse generator means connected to said output means, and having means for establishing a first pulse generator means interpulse period in response to a sensed natural heartbeat and a second, different pulse generator means interpulse period in response to a pulse generator means output pulse, the improvement which comprises means for selectively altering at least one of said first and second interpulse periods to provide substantially identical interpulse periods in response to natural heartbeats and pulse generator means output pulses.
- 7. In a demand cardiac pacemaker of the type having input and output means adapted for connection to the heart, the input means including means for sensing natural heartbeats, having pulse generator means connected to said output means, and having timing circuit means differently responsive to natural heartbeats and pulse generator means output pulses for establishing a first pulse generator means interpulse period in response to natural heartbeats and a second pulse generator means interpulse period in response to pulse generator means output pulses, the improvement which comprises means connected to said timing circuit means and responsive to externally generated signals for selectively rendering said timing circuit means substantially identically responsive to natural heartbeats and pulse generator means output pulses.
- 13. In a demand cardiac pacemaker of the type having input and output means, the input means including means for sensing natural heartbeats, having pulse generator means connected to said output means, and having timing circuit means connected to said sensing means including first capacitance means for controlling the pulse generator means output pulse frequency in accordance with the first capacitance means charging time and means responsive to a pulse generator means output pulse for changing the charging time of said first capacitance means, the improvement which comprises means connected to said charging time changing means and responsive to externally generated signals for rendering said charging time changing means responsive to natural heartbeats on alternate ones of said externally generated signals.
- 16. In a demand cardiac pacemaker of the type having input and output means, the input means including means for sensing natural heartbeats, having a pulse generator means connected to said output means, having first timing means for controlling the pulse generator means output pulse frequency, having means for resetting said first timing means on the occurrence of either a natural heartbeat or a pulse generator means output pulse and having means for altering said pulse generator means output pulse frequency for one pulse cycle following a pulse generator means output pulse, the improvement which comprises means interconnecting said resetting means and said altering means and responsive to externally generated signals for enabling said altering means on the occurrence of natural heartbeats and pulse generator means output pulses following alternate ones of said externally generated signals.
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21. In a demand cardiac pacemaker of the type having input and output means, the input means including means for sensing natural heartbeats, having pulse generator means connected to said output means, and having hysteresis means connected to said sensing means for providing different pulse generator means standby and pacing rates, the improvement which comprises means responsive to externally generated signals for selectively connecting said hysteresis means to said pulse generator means.
Specification