Artificial cardiac pacemaker

摘要

An artificial cardiac pacemaker for use with a heart comprises an output feedback preventing circuit for applying stimulating output pulses developed by the pacemaker to a heart while preventing the pulses from being fed back into the pacemaker and for detecting cardiac signals from the heart. A selective converter circuit is connected to the output feedback preventing circuit and functions to convert negative cardiac signals from the heart into positive signals and apply the signals to a low pass filter circuit which filters the signals to eliminate high frequency noise. A resettable circuit for the refractory period is connected to receive the filtered signals and establishes a predetermined refractory period after each QRS signal from the heart and provides a corresponding trigger signal to a delay circuit which responds thereto to provide a trigger pulse after a predetermined time delay. A generator circuit is connected to the delay circuit and responds to the trigger pulses to accordingly generate output pulse signals. An output stimulating circuit has an input connected to the generator circuit and an output connected to the output feedback preventing circuit and is driven by the pulse signals to produce corresponding stimulating output pulses suitable for heart stimulation.