[Assessment of arterial distensibility by ambulatory monitoring of QKD interval. Reproducibility of the method].

Abstract

We have proposed the use of the ambulatory monitoring of the timing of Korotkoff sounds (QKD interval) to assess arterial distensibility. This interval is inversely linked to pulse wave velocity. The study of its variations according to spontaneous blood pressure changes during 24 h allows to calculate indices of arterial distensibility independent of actual blood pressure. A normalized QKD100-60 is calculated as the value for a 60 batt/min heart rate and a 100 mmHg systolic blood pressure from the individual multivariate linear relationship between these 3 variables. This interval decrease with arterial distensibility. We tested the reproducibility of this method in 28 normal subjects (14 males, 14 females, aged 43 +/- 16 years) who underwent two 24 h recordings during daily routine separated by one week. Standard deviation of differences for QKD100-60 was 12 ms, the coefficient of variation 6% and the coefficient of repeatibility 24 ms. So QKD100-60 shows a good reproducibility in the same range that 24 h blood pressure means.