Heart pacemaker battery saving circuit - has pulse shaper output fed to alternative trigger stages to modify pulse trains

The battery operated heart pacemaker has a control circuit which at low potentials permits the use of minimum current within safe limits. The device also has an electrode connected to a preamplifier followed by a trigger stage. Its output is fed to a monostable multivibrator acting as a pulse shaper, forming rectangular pulses of opposite polarity. One set is fed to a second trigger stage which also limits the upper frequency of the trigger pulses. A third trigger stage and multivibrator form an alternative path to modify the pulses and fire an increased battery life. The first path establishes the basic rate of the pulses. The recurrence frequency of the pulses are separated at the end of the life of the battery from normal operating conditions.