Fiducial Point Estimation Solution for Impedance Cardiography Measurements

ICG (impedance cardiography) is in parallel to ECG (electrocardiography) an important indicator of the functioning of the heart and of the overall cardiovascular system. Adding the ICG to ECG measurement functionality into the wearable devices improves the quality of health monitoring, as the ICG reflects relevant hemodynamic parameters (informative time intervals, but also the stroke volume and cardiac output and their variability). The most challenging task of the ICG signal processing is to extract the key points B, C, X of the cardiac period - start, peak-location, and value at this point and the end of the LVET (left ventricular ejection time) sub-period in the cardiac cycle. A novel block diagram and analog implementation of it has been proposed, analyzed, and discussed, with discussion of the benefits of the proposed solution. The proposed solution enables developing of relatively simple very power-efficient solutions, monitoring the ICG values of the person with smart and efficient data acquisition and processing.