This deliverable describes the work developed in the course of the Workpackage 6 of the euHeart project, on the planning of RadioFrequency ablation for patients suffering from Atrial Fibrillation (AF) and Ventricular Tachycardia (VT). New advances towards the personalization of atrial models are first reported by evaluating the coherence of a rule-based fiber placement method with respect to some available high resolution imaging of the atria and comparing simulated and measured local activation times. Atrial electrophysiological models are then used to investigate the role of gaps in ablation lesions on the cross gap conduction. Preliminary results show that that lesion gaps which are isolating under electrical remodeling, might be conductive under physiological conditions which may explain low success rates of radiofrequency ablation of AF. Another application of electrophysiological modeling consists in finding the pulmonary veins which are most likely to reconnect during the healing process after an ablation procedure. A sensitivity analysis has been devised to quantify the degree of isolation of each vein as a function of the threshold used to segment scars in late enhancement MR images acquired from patients awaiting AF redo-procedures. For the study on Ventricular Tachycardia (VT), personalization of an electrophysiological model of the ventricles has been carried out successfully on 2 patients for whom a non-contact electrophysiological mapping system was used during a VT Stim procedure. In those 2 cases, VT could be induced during the procedure and the location of exit points has been shown to match regions of high heterogeneity in terms of action potential duration (APD) restitution slope parameters. Similar parameter maps have been established on patients with ischemic heart diseases (IHD) and dilated cardiomyopathy (DCM) leading to low heterogeneity of APD restitution slope parameters for DCM patients and relatively higher values for IHD patients. On those 2 patients, a comparison between simulated VT exit points and observed ones has been performed showing good correlation. The advantage of simulating a VT Stim procedure is demonstrated by allowing to vary the stimulation points and to estimate the transmurality of VT reentry circuits.