The cardiac simulator   (see A2, A11, A12, A13, A22, A23, C13, C20, C28, C34, C35, C46, C48, D7). Despite the satisfying results obtained in the field of valvular prostheses (12 000 yearly implementations in France), many problems remain which are due to thromboembolic incidents, as the 10 years mortality ratio for implemented patients ranges from 30 to 50%. Complications are influenced by the kinematics and the design of the prosthesis. With a view to characterize a valvular prosthesis' comportment before a clinical use, a cardiovascular simulator was created within the laboratory. This simulator is the improvement of a simple ventricular activator formerly conceived and realized at the IMFM (Marseilles' Fluid Mechanics Institute). This new simulator innovates by producing independent contractions of models of left auricle and ventricle, so that physiological flows conditions may be recreated. The activation of these two cavities is based on the same principle. A computer (fitted with the Labview software) generates a driving signal and sends it to a hydrodynamic generator, which debts fluid in a hermetic cage containing the cavity model. The alternatively positive and negative debts induce the contraction first, and then the expansion of the cavity. The models of auricle, ventricle and aorta are made of silicone after moulds of cardiovascular voids.       Double activation simulator Besides the respect of anatomic shapes, these moulds possess elastic characteristics which are close to the physiologic reality. To complete this device, the capacitive effects of the arterial system, and the resistive effects of the systemic bed are respectively simulated by a compliance and a resistance. The circulation of the fluid (of same viscosity as blood) is insured by the complementary actions of contractions/expansions of the atrial and ventricular cavities, and the opening/closing movements of two aortic and mitral valvular prostheses.