programs stored in rom 55 and used by microprocessor 26 these programs include system supervisory programs detection algorithms for detecting and confirming various arrhythmias and programming for implementing the flow chart of fig4 as well as storage programs for storing in external memory 57 data concerning the functioning of module 12 and electrograms provided by atrial and or ventricular cardiac lead s 20 fig1 timers 51 and 52 and associated control software implement standard timing functions required by microprocessor 26 microprocessor 26 receives various status and control inputs from the interface 24 and defibrillator 16 on buses 38 and 40 and produces the control signals on these buses and bus 32 necessary for various functions including normal rate responsive pacing of the atria and or ventricle skeletal muscle stimulation and defibrillation more specifically the atrial and ventricular pace control inputs derived from the signals received from the heart on leads 18 and 20 determine the respective types of atrial and or ventricular pacing to be delivered to the heart details of this function are described in commonly assigned u s pat no 4 869 252 to norma louise gilli issued sep 26 1989 entitled 34 apparatus and method for controlling pulse energy in antitachyarrhythmia and bradycardia pacing devices 34 and incorporated herein by reference the skeletal muscle stimulator 30 shown in fig1 receives input signals from microprocessor 26 over the skeletal muscle stimulation control bus 32 in addition the.