A New Measure of Pulse Rate Variability and Detection of Atrial Fibrillation Based on Improved Time Synchronous Averaging

Figure 4

Pulse wave and its derivative with an applied threshold. The derivative of the original signal is almost entirely unaffected by baseline wander and shows clearer segmentation points. The first zero point of the derivative before each threshold point was defined as the period segmentation point, and the corresponding segments of the original signal between two adjacent period segmentation points were single-period waveforms.