parameters such a differentiation between the two operating states can also be effected by correspondingly influencing the parameter controlled addressing process in the case of the exclusion of certain interval ranges the interval values which are applicable instead i e the limit interval values of the frequency ranges 34 excluded 34 during stimulation operation are fed into the memory locations associated with the respective parameters fig2 is a top view of a control member 200 for external programming and control by the physician 39 s hands on display 201 in the left half of the figure the functional dependency of the heart frequency is shown in dependence on the systolic intervals to be detected with the display being made separately or superposed for different operating states the illustration corresponds to the values stored in pacemaker memory 9 with it being possible to either give a fixed functional relationship or the stimulation frequencies to be maintained for the systolic intervals determined in the implanted system are calculated on the basis of the values found when sine rhythms did exist it is also possible to program in preferred stimulation frequencies to be maintained for predetermined value ranges of the systolic intervals as well as differences in the frequencies which belong to interval values for different operating modes so that these correction values can be used when the mode is changed etc processing of the heart and stimulation frequencies takes place in the form of the reciprocal interval between r waves so that proportionality.