| 摘要 |
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. |
