Using the Photoplethysmography Technique to Improve the Accuracy of LVET Measurement in the ICG Technique

Abstract

The stroke volume is an important cardiac blood flow hydraulic parameter that can be used to assess whether the pump function of the heart is normal. Non-invasive stroke volume measurement is currently performed using impedance cardio plethysmography (ICG). The ICG method is used to detect the amount of changes in the volume of thoracic cavity generated by the heartbeat and to estimate the stroke volume. Left ventricular ejection time (LVET) is an important parameter in stroke volume measurement with ICG technology. However, the ICG signal is susceptible to artificial noise interference, which leads to inaccurate LVET and miscalculation of stroke volume. In order to solve this problem, this paper uses the photoplethysmography (PPG) sensor to measure LVET, and assesses whether the LVET measured by the PPG sensor is more accurate than the LVET measured by the ICG. The results show that using the PPG sensor can indeed improve the accuracy of the LVET measurement, and that the closer the PPG sensor is placed to the heart, the more stable and accurate the measured LVET will be.