In this proof of principle study, we investigated the effectiveness and safety of hemodynamic support with the Intra-Ventricular Membrane Pump (IVMP). The IVMP was implanted into the apex of the left ventricle. Hemodynamic assessment was performed in six ex vivo beating porcine hearts (PhysioHeart platform). The cardiac output (CO), mean arterial pressure (MAP), coronary flow (CF) and pulse pressure (PP) were obtained before and during IVMP support and reported as means ± standard deviations. In two additional visualization experiments, the integrity of the mitral valve was assessed during IVMP support. We found a significant increase of the CO (+1.4 ± 0.2 L/min, P < .001), MAP (+13 ± 6 mm Hg, P = .008), CF (+0.23 ± 0.1 L/min, P = .004), and PP (+15 ± 4 mm Hg, P = .002) during IVMP support, when compared to baseline. No interference of the IVMP with mitral valve function was observed. An increase of premature ventricular complexes (PVC) was observed during support with the IVMP (mean PVC-burden 4.3% vs. 0.7% at baseline), negatively influencing hemodynamic parameters. The IVMP is able to significantly improve hemodynamic parameters in a co-pulsatile fashion, without hampering the function of the mitral valve. These findings provide a basis for future development of a catheter-based IVMP.