The relation between abnormal ventricular activation and corresponding ECGs still requires additional understanding. The presence of disease breaks the equivalence in equivalent dipole layer-based $ECG$ simulations. In this study, endocardial and epicardial patches were introduced to simulate abnormal wave propagation in different types of substrates. The effect of these different types of substrates on the $QRS$ complex was assessed using a boundary element method forward $heart/torso$ and a 64-lead body surface potential map (BSPM). Activation was simulated using the fastest route algorithm with six endocardial foci and $QRS$ complexes corresponding to abnormal patch activation were compared to the $QRS$ complexes of normal ventricular activation using correlation coefficient $(CC)$ . Abnormal patch activation affected both $QRS$ morphology and duration. These $QRS$ changes were observed in different leads, depending on substrate location. With insights obtained in such simulations, risk-stratification and understanding of disease progression may be further enhanced.