Cardiac electrical dyssynchrony, due to conduction disorders such as left bundle-branch block (LBBB), leads to heterogeneous myocardial contraction, potentially causing reduced pump function. Cardiac resynchronization therapy has been shown to be an effective treatment to improve pump function in patients with LBBB by restoring ventricular electrical synchrony through ventricular pacing. In this context, computational cardiovascular modelling is increasingly recognized and used as a valuable tool for investigating pathological conditions and evaluating treatment strategies. The main goals of our research involve modelling the effects of dyssynchrony on regional tissue mechanics and global cardiac pump function as well as investigating the effect of different pacing strategies. Using patient-specific cardiac geometries, electrical activation maps were calculated using an Eikonal model on a 3D biventricular geometry. The Purkinje network was identified using a probabilistic approach based on non-invasive ECG data. The activation times were then averaged within the AHA regions and used as inputs in CircAdapt, a cardiovascular model capable of describing heterogeneous mechanical activation. The CircAdapt model was calibrated to match MRI-derived variables such as end-systolic and end-diastolic volumes. Simulated strain, regional myocardial work, and hemodynamic function were compared for each pacing strategy. Using this coupled approach, we can confirm the existence of a non-trivial relationship between electrical synchrony, mechanical homogeneity, and hemodynamic function. Furthermore, we can predict the pacing strategy associated with the most synchronous electrical activation and homogeneous mechanical work distribution.