WHY DOES THE WAVEFORM OF A PULSE WAVE FEATURE “ONE WAVE WITH THREE TWISTS”

Taking the Chinese idiom “one wave with three twists” as the entry point, this paper systematically interprets the physical and physiological mechanisms underlying the “one wave with three twists” morphology of human pulse wave. Characteristic segments of a typical pulse wave consist of the ascending limb, primary systolic peak, tidal wave, dicrotic notch, dicrotic wave, and descending limb, which correlate with physiological events including ventricular ejection, elastic reservoir of blood vessels, valve closure, and peripheral resistance. Drawing on transmission-line theory, arteries are analogized to elastic transmission conduits to illustrate that, as pulse waves propagate across the arterial tree, incident waves superpose with reflected waves originating from branching sites, stenotic segments and vessel terminals. This unveils the formation principle for the spatiotemporal “one wave with three twists” fluctuations in pulse waves of pressure and flowrate. The clinical value of pulse wave features for cardiovascular health assessment is further discussed. Through vivid metaphors and an interdisciplinary perspective, this paper reveals the intrinsic link between everyday-language descriptions and life-science mechanisms, highlighting the bridging role of biomechanics in deciphering biological phenomena and advancing clinical practice.