Subject-Specific Cardiovascular Signatures Revealed by Arterial Pulse Signals in Patients with Heart Diseases—Part I: General Cases

Background/Objectives: This study evaluates whether cardiovascular (CV) parameters derived from noninvasive arterial pulse signals can capture subject-specific physiological characteristics and longitudinal changes in patients with diverse heart diseases. Method: Arterial pulse signals at the radial artery (RA) and carotid artery (CA) of each patient were successfully recorded from all 18 patients using micro-fabricated tactile sensors. Signal quality was screened before analysis, and the accepted signals were analyzed using a single-degree-of-freedom time–frequency (SDOF-TF) framework. Key CV parameters, including time-based indices—heart rate (HR), heart rate variability (HRV), respiration rate (RR), and respiration modulation (RM), as well as harmonic amplitudes and normalized arterial pulse waveform (APW)—were extracted from measurements at rest and post-exercise across three rehabilitation visits in 18 patients with heterogeneous CV conditions. Longitudinal changes in CV parameters within subjects and variability between subjects were assessed. Results: Compared with a healthy reference, the patients exhibited heterogeneous CV profiles, with lower HRV in all patients except one with AF, who showed elevated HRV, and generally reduced post-exercise CV responses. Higher-order harmonic amplitudes were attenuated at the RA, while CA-derived APW measurements showed greater sensitivity to systolic upstroke slope. Marked inter-subject variability was evident in at-rest CV parameters and 5-min post-exercise responses. Longitudinal CV responses varied across rehabilitation visits, potentially reflecting multiple contributing factors. Conclusions: The 100% pulse acquisition rate supports the feasibility of the tactile sensor technology for pulse measurement, and the combined sensor technology and SDOF-TF framework enable quantitative characterization of shared and individualized CV patterns in cardiac patients and their post-exercise recovery, including time-based indices, harmonic signatures, site-specific differences, and interactions among CV parameters. These findings warrant further investigation in larger cohorts with appropriate physiological reference measurements.