Monitoring of respiration, seismocardiogram and heart sounds by a PVDF piezo film sensor

In-vivo monitoring of patient's cardiac mechanics via seismocardiogram was recently introduced (demonstrated). Usually, seismocardiogram is recorded using accelerometers placed on patient's sternum. This study present the ability of a PVDF piezo film transducer to record the mechanical activity of the heart (seismocardiogram and heart sounds) and also of the respiration-related, thorax motion. The transducer was positioned on patient's sternum and held in position by a chest strap. Patient's ECG signal was simultaneously recorded to provide a timereference of the cardiac activity. The piezoelectric sensor was able to record respiratory movements, seismocardiogram and heart sounds: These signals can be obtained from the recorded signal by applying simple filters. The seismocardiogram waveform appears to be dependent on the various phases of the respiratory cycle. The recorded signal from the sole piezoelectric sensor can provide relevant information such heart rate, respiratory rate, timing of mechanical event within the cardiac cycle, etc.