Theoretical Modeling on Monitoring Left Ventricle Deformation Using Conformal Piezoelectric Sensors

Left ventricular (LV) volume is a crucial indicator for the assessment of the heart function. However, the current clinical practice cannot be used to monitor the LV volume continuously or warn patients with high risk in time before heart attack occurs in everyday life, resulting in high mortality and morbidity. Here, we theoretically validate the potentiality of a conformal real-time LV deformation-monitoring sensor using piezoelectric materials. The electromechanical relationship between the deformation of the hearts and output voltage signals of the sensors is demonstrated first. End-to-end displacements and deformations of piezoelectric films under cyclic load are derived from the output voltage signals and then compared with experimental values. Then, the real-time LV volumes of a pig and a cow are derived and compared by employing the experimental output voltage signals of the flexible sensor mounted on the LV surface. Finally, by employing the LV volume data of healthy people and patients with various heart diseases in the literature, the theoretical output voltage signals of flexile sensors when mounted on LV surface are calculated and compared. These predicted output voltage signals show significant differences for people with different kinds of cardiac diseases. The results in this study demonstrate that the conformal piezoelectric sensor is fully potential to continuously monitor the cardiac deformation and correspondingly provide timely warning for cardiologists and patients with heart diseases.