Because Radio Frequency Identification (RFID) technologies are very widespread, the influence of these electromagnetic fields on implantable cardiac pacemakers should be evaluated. The results were obtained modelling pacemakers, electrodes and sources using the DUKE body model and simulating different setups with the numerical simulation program SEMCAD X (Speag Zurich). The obtained disturbance voltages at the input of the cardiac pacemaker were used to gain information about the difference between left and right pectoral implantation method and between unipolar and bipolar electrode setup. Furthermore the results were compared to thresholds given by the standards DIN EN 45502-2-1 and VDE 0848-3-1. The results show that some exposure situations with several sources are capable of influencing the pacemaker and therefore a possible threat for the wellbeing of the person wearing a cardiac pacemaker.