In vitro characterization of bileaflet Mechanical Heart Valves closing sound

Due to the asynchronous closure of the leaflets , the closing sound of a bileaflet Mechanical Hearth Valve (MHV) is characterised by the presence of two peaks in the time domain. The closing sounds of four commercial MHVs have been acquired in vitro using the Sheffield Pulse Duplicator, under different working conditions to simulate as many physiological ones. The MHVs closing sounds were detected by a commercial apparatus (Myotis 3c, Cardiosignal GmbH). Closing sound spectra (10-22 kHz) have been statistically analysed and compared. A preliminary classification of the tested MHVs is herewith presented; differences in their phonographic behaviour are briefly discussed. This work would allow moving towards the early phonocardiographic diagnosis of bileaflet MHVs malfunction due to endothelial pannus deposition and/or thrombosis.