Rate and A-V delay generator for heart pacemaker

Apparatus for producing atrial and ventricular timing signals for a pacemaker with independent control of ventricular rate and atrial-ventricular delay, comprising:

• means for generating first and second voltage signals, one of said voltage signals comprising a voltage ramp signal and the other of said voltage signals comprising a reference voltage;
• first voltage comparison means connected to receive said first and second voltage signals and operative to produce a first output signal when said voltage ramp signal reaches a predetermined relationship with said reference voltage;
• voltage offset means connected to receive one of said voltage signals and operative to produce an offset voltage signal which differs therefrom by an offset voltage;
• second voltage comparison means connected to receive said voltage offset signal and the other of said voltage signals and operative to produce another output signal when said voltage offset signal and said other voltage signal reach a predetermined relationship, said output signal being spaced in time from said first output signal according to the amount of said offset voltage;
• and
• means for adjusting the amount of said offset voltage, whereby the earlier and later output signals provide atrial and ventricular timing signals, respectively, and whereby the ventricular rate may be controlled by adjusting the relationship of said reference voltage and said voltage ramp signal, and the atrial-ventricular delay may be independently controlled by adjusting the amount of said offset voltage.