Pulse Arrival Time Techniques

For over 90 years, researchers and clinicians have worked on systems to noninvasively measure pulse wave velocity, with the ultimate goal of measuring continuous, cuffless blood-pressure. The design of multisensor systems to make two or more measurements of the pulse wave along the human arterial tree has become the hallmark of these efforts. Pulse arrival time measurements are traditionally made by detecting a first fiducial point on the electrocardiogram (ECG) waveform, and second fiducial point on a distal pulsatile waveform, such as the photoplethysmogram (PPG) or impedance cardiogram (ICG). By looking at the time difference between these two fiducial points, an approximation for pulse wave velocity can be calculated. Some other challenges exist in transforming the pulse arrival times into absolute blood pressure, but these have been largely overcome, as evidenced by the clinical-grade systems that are commercially available in the marketplace today.