Abstract

Importance of heart rate variability (HRV) came into existence with the observations of Hon and Lee in 1965 and had been used ever since for objective assessment of automatic nervous system (ANS) as well as in intensive care monitoring. Blood pressure (BP) variability has been investigated less extensively because of invasive nature or high cost of beat-to-beat BP measurement. Peripheral blood flow (PBF) variability and morphology index variability (of the peripheral pulse) have also been sparingly studied because of the paucity of physiological and clinical correlation. In continuation of these studies, the peripheral pulse from the right wrist has been recorded in 207 control subjects and 207 patients (suffering from different diseases) in resting condition (supine), and HRV, blood flow variability and morphology index variability has been derived from this data. To take care of large scatter in the value of variability parameters in control subjects, multiple observations have been made on the subject, and the average value of variability parameter has been considered for analysis in conformity with central limit theorem (CLT). The control data has shown a remarkable decrease in standard deviation and coefficient of variation and enabled use of parametric statistical analysis. Comparison of variability parameters in health and disease has been observed to be consistent with the nonparametric analysis namely Mann– Whitney test , with a correlation coefficient of 0.8675. Based on this analysis, general and specific parameters, which change in the presence of a disease, have been identified for different diseases. The observations are reported here.

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