A new mathematical model of wrist pulse waveforms characterizes patients with cardiovascular disease - A pilot study

Abstract

The purpose of this study was to analyze and compare a series of measured radial pulse waves as a function of contact pressure for young and old healthy volunteers, and old patients with cardiovascular disease. The radial pulse waves were detected with a pressure sensor and the contact pressure of the sensor was incremented by 20gf during the signal acquisition. A mathematical model of radial pulse waveform was developed by using two Gaussian functions modulated by radical functions and used to fit the pulse waveforms. Then, a ratio of area (r_A) and a ratio of peak height (r_PH) between percussion wave and dicrotic wave as a function of contact pressure were calculated based on fitted parameters. The results demonstrated that there was a maximum for waveform peak height, a minimum for r_A (r_A^min) and a minimum for r_PH (r_PH^min) appeared as contact pressure varied. On average, older patients had higher peak amplitude and a significantly smaller r_A^min (p<0.001) and r_PH^min (p<0.02) than the young and old volunteers. The r_A^min and r_PH^min calculated with the mathematical model had moderate to strong positive linear correlations (r=0.66 to 0.84, p<0.006) with those directly calculated without the model. The receiver operating characteristic (ROC) analysis showed that the r_A^min calculated with the model and the contact pressure measured at the r_A^min had good diagnostic accuracy to distinguish healthy volunteers vs. diseased patients. Therefore, using the mathematical model to quantitatively analyze the radial pulse waveforms as a function of contact pressure could be useful in the diagnosis of cardiovascular diseases.

Keywords: Cardiovascular disease; Contact pressure; Gaussian function; Mathematical model; Radial pulse waves.