The development of innovative types of electrodes and the further development of existing products account for a large part of the resulting costs for a company. With the help of suitable software, changes of the constructions can be recorded and certain simulations, e.g. the occurrence of interactions in the electric field, can be carried out before the actual prototyping. Barold and Kucher evaluated far-field atrial oversensing by left ventricular electrode displacement in CRT-D patients with left ventricular undersensed activity during the blanking periode [1]. Lewicka-Nowak and co-workers found 11% far field R-wave sensing by atrial electrode at the right atrial appendage versus 1% at the Bachmann's bundle [2]. Taieb and co-workers analysed left atrial far-field sensing by left ventricular electrodes in 8.5% of CRT devices with potential hazard in CRT [3]. Atrioventricular nodal ablation in CRT patients with atrial fibrillation is a class IIa and level B indication for ablation and Aune and co-workers found a significant improvement of ventricular capture from 68% to 98% after atrioventricular nodal ablation [4]. Barold and Herweg analysed after