The Morphology of Digital Volume Pulse Wave in Health and Hypertension Recorded Plethysmographically

The present investigation aims at clarifying the pathogenesis of hypertension by evaluation of 11 parameters derived from geometrical analysis of finger pulse waves, which were recorded plethysmographically. 259 subjects (male 136, female 123) from 20 to 80 years were divided into 128 normotensives and 131 hypertensives and were subdivided into 23-39, 40-59, and over 60 years groups.In normotensives, the contours of pulse waves change with advancement of age. Statistically significant age changes were observed in an increase of the relative crest time, inclination time, ratio of amplitude of dicrotic waves to peak amplitude and in the decrease of elasticity index in both sexes.When male hypertensives are compared with the male normotensives, the statistically significant interaction betwenn age and blood pressure is observed in the relative crest time and elasticity index. The average relative crest time and elasticity index in male normotensives are significantly low in the case of relative crest time and significantly high in the case of elasticity index compared with those of hypertensives in age group of 20-39 and 40-59 respectively. The diminition of dicrotic wave in male and female hypertensives in ages from 20 to 39 suggests that the increase of peripheral resistance may be involved the pathogenesis of essential hypertension.Over the age of 60, none of the parameters indicate a significant difference between the normal and the hypertension group.Males and females over the age of 60 were put together and divided into five subgroups according to systolic and diastolic blood pressure. In the subjects with only systolic elevations but diastolic normal blood pressure levels, the parameters concerned with anacrotic limbs, viz. relative crest time, elasticity index, inclination time and angle of anacrotic limb, revealed similar values to those of normotensives, while other parameters derived from catacrotic limbs, such as the percentage of descending time at 1/2 or 1/4 peak amplitude, relative amplitude at 1/2 or 1/4 the distance of the diastolic phase in subjects with systolic hypertension show lower values than those of other types of hypertension. The changes of parameters concerned with anacrotic limb in elderly systolic hypertensives may reflect the decrease of elasticity in the peripheral vasculature which is common in normotensives with advancement of age, but the concave direction of the slope of the catacrotic limb in elderly sysotlic hypertensives suggests that the resistance of peripheral circulation remains at the level of normotensives.