The contraction of the heart is the consequence of the synchronized reaction of the myocardium to the propagation of a non-linear electrophysiology wave. Such scenario, however, can be altered in pathological conditions, such as when ventricular tachycardia or ventricular fibrillation manifest. These phenomena are related to the non physiological impulse propagation within the tissue, which are often triggered by myocardial infarction. In particular, the scar region is known to act as a support for the generation of scroll waves owing to the high conductivity difference between healthy and pathological tissue. While the dynamics and formation of arrhytmogenic patterns is widely studied in literature, their consequences on the cardiac hemodynamics are rarely taken into account. In this work, we aim at investigating what are the effects of ventricular fibrillation on the blood flow and, in particular, determine what pathological electrophysiology patterns are the most harmful to the normal vortex dynamics. To this aim, the whole cardiac anatomy of a patient has been reconstructed from medical images (CT scans) and realistic ischemic regions have been included in order to trigger fibrillation patterns. The electrophysiology is then solved though a bidomain model coupled with suitable cellular models encompassing the hetoregeneity of the myocardium owing to the presence of healthy tissue, peri-infarct region and scar tissue. The corresponding hemodynamics is then solved by integrating the Navier-Stokes equations, which are discretized using a staggered finite differences complemented with immersed boundary techinques. The resulting multi-physics system can be then exploited as a predictive tool to reproduce ventricular fibrillation cases and try to understand what is the optimal intervention in order to restore the cardiac function.