Aim: Computational simulations of the electrophysiology up to the ECG have seen a severe rise in popularity over the recent years. Yet, so far, the impact deformation has on the ECG is still not completely understood. In this study we present a fully coupled electro-mechanical computational model of the complete heart embedded into a torso. Compared to previous studies this gives us the ability to incorporate apico-basal, as well as rotational movement of the ventricles more accurately. Methods: We combined two validated frameworks of electrophysiology and mechanics to create a strongly coupled electro-mechanical one. To obtain a high comparability to a prior study, where cine-MRI was used to map deformation, the same geometrical model of heart and torso, stimulation pro-file, apico-basal heterogeneities, and ECG-lead positions were used. Results: Changes in amplitude of the T-wave were contradicting to some previously published results. Our model predicts a slight increase of 8% in T-wave amplitude in Einthoven II lead with deformation, instead of a decrease shown in a previous study. Further, the time to T-wave peak, which could be interpreted as the QT-interval, increased by 7ms. When we decoupled the electrophysiology from the mechanics for the ECG calculation and artificially shifted the membrane voltages by +75ms, such that the repolarization lies completely in the isovolumetric relaxation phase (without influencing deformation), morphology changes could be reverted. Conclusion: Our results highlight that the impact of deformation is not as prominent as previously shown. The overall effect on the T-wave is dependent on the temporal relation of the electrical repolarization with the diastolic phase. Overall though, the effect seems to be almost negligible in terms of amplitude as well as morphology.