Assessing spontaneous baroreflex in aged with pulse-pulse intervals and pulse amplitudes

Cardiac autonomic dysfunction is a serious condition in the elder subjects. Baroreflex sensitivity (BRS) by measuring pulse intervals and blood pressure has been proven as an effective indicator. This paper proposes a novel index by substitution blood pressure with amplitudes of pressure pulse. We recruited 61 subjects divided into two groups: healthy young subjects (Group1, n=33), healthy elders (Group2, n=28). The wrist pulse pressures of each subject were measured for 5 minutes to obtain pulse-pulse intervals and amplitudes then applied within the spontaneous sequence technique to calculate the pulse-pulse interval and amplitude ratio (PAR). We verified the reproducibility of PAR and agreement with spectral analysis of heart rate variability in group1 participants. We discovered significant differences between different groups in PAR (Group1 vs. Group2: 0.90±0.42 vs. 0.62±0.27, P=0.010). In contrast with measurements of BRS, this study proposes a simple approach without the necessity of blood pressure calibration or professional expertise to conduct measurements, thereby providing a convenient method for assessing autonomic function at home.