1 Laboratoire de Biomécanique Appliquée, UMRT24 Université Gustave Eiffel - Aix Marseille Université, Faculté de Médecine secteur-Nord, Marseille, France. Electronic address: dorian.sweidy@univ-eiffel.fr.
2 Laboratory of Cardiovascular Fluid Dynamics, Mechanical Industrial and Aerospace Engineering, Concordia University, Montreal, QC, Canada. Electronic address: andrew.mathyssen@mail.concordia.ca.
3 Laboratory of Cardiovascular Fluid Dynamics, Mechanical Industrial and Aerospace Engineering, Concordia University, Montreal, QC, Canada. Electronic address: kowsar.teimouri@mail.concordia.ca.
4 Laboratoire de Biomécanique Appliquée, UMRT24 Université Gustave Eiffel - Aix Marseille Université, Faculté de Médecine secteur-Nord, Marseille, France. Electronic address: wei.wei@univ-eiffel.fr.
5 Laboratory of Cardiovascular Fluid Dynamics, Mechanical Industrial and Aerospace Engineering, Concordia University, Montreal, QC, Canada. Electronic address: wael.saleh@concordia.ca.
6 Laboratory of Cardiovascular Fluid Dynamics, Mechanical Industrial and Aerospace Engineering, Concordia University, Montreal, QC, Canada. Electronic address: lyes.kadem@concordia.ca.
7 Laboratoire de Biomécanique Appliquée, UMRT24 Université Gustave Eiffel - Aix Marseille Université, Faculté de Médecine secteur-Nord, Marseille, France. Electronic address: morgane.evin@univ-eiffel.fr.

Blunt trauma is a major complication of high-speed motor vehicle crashes, often resulting in injuries of varying severity. Cardiac trauma accounts for about 18% of blunt chest injuries, the third most common death cause. Experimental studies described cardiac consequences after impact; however, none have captured the ventricular flow behavior during the impact itself. In this study, we test the feasibility of a custom-made left-heart-simulator to recreate acute time-controlled impacts on the left ventricle and analyze the resulting flow disturbances. The setup includes silicone models of the left atrium, left ventricle, and aorta, equipped with bioprosthetic mitral and aortic valves. The working fluid is a 60/40 mixture of distilled water/glycerol. The ventricle is enclosed in a hydraulic chamber filled with the same fluid, while a piston-cylinder system driven by a linear motor controls contraction and relaxation. To simulate impact, a 3D-printed impactor is positioned facing the ventricle and actuated by a second linear motor connected through two orthogonally-mounted syringes. Five impact timings during the cardiac cycle are tested. Flow in the ascending aorta is measured, and pressure sensors in the ventricle and aorta record instantaneous variations before, during and after impact. During impact, significant alterations in both systolic and diastolic ventricular pressure are observed, with 52% systolic pressure increase during systolic impacts and 422% diastolic pressure decrease during diastolic impacts. Flow velocity fields reflect atypical ascending outflow toward the mitral valve. This work provides new insights into trauma-induced intraventricular flow dynamics and contributes to understanding cardiac injury mechanisms in sudden impacts.