(Received: xx Xxxx xxxx.Accepted: xx Xxxx xxxx) Heart valve bioprostheses usually do not need anticoagulation; however they are threatened by an increasing with time risk of degeneration. The aim of this work is to find a magnetic sensor, which could be integrated in a bioprosthesis, monitoring the prosthesis in such a way that allows to confidently forecast the failure. Several models of magnetic sensors have been tested in a hydro- dynamic setup specifically manufactured, where the heart pressure, frequency, and cardiac flow were simulated. Small pieces of amorphous soft magnetic material were stuck to the cusps of a bioprosthesis, and through a carefully designed electronic system, the movement of the cusps is detected at the same time that the image of the working valve is captured by a digital camera. The small pieces placed in the valve are under an external applied field of few Khz, and the magnetiza- tion signal of the pieces is acquired by means of two series connected coils. The movement of the pieces, at a cardiac simulated rhythm, induces a modulation in the amplitude of the signal detected in the secondary coils, with the same frequency as the valve movement. The modulated signal is analysed with a system consisting of an amplifier and a synchronous demodulator. The analysis of the electronic signal together with the image allows characterizing the signal changes when the valve begins to fail, preventing the bioprosthesis functional failure.