| 摘要 |
<p>An implantable programmable pacemaker includes a sensor for measuring oxygen saturation levels in blood on a periodic basis, e.g., every 15 seconds, while the pacemaker is operating in its programmed mode of operation. The energy of stimulation pulses generated by the pacemaker is automatically adjusted, as required, in order to maintain a prescribed level of oxygen saturation in the blood. At least a minimum level of oxygen saturation is presumed when the stimulation pulses are of sufficient energy to effectuate capture. Hence, the oxygen saturation level is monitored to provide an indication of whether capture has been lost, and if so, to increase the stimulation energy. In one embodiment, the stimulation energy is increased by first increasing the pulse width of the stimulation pulse a prescribed amount. After the pulse width has been increased a maximum amount, and if capture is still lost, the stimulation energy is further increased by increasing the pulse amplitude a prescribed amount. After the pulse amplitude has been increased a maximum amount, and if capture is still lost, the operating mode of the pacemaker is changed, and the stimulation energy is reset to an appropriate value. <IMAGE></p> |
