Asymmetric properties of long-term and total heart rate variability.

Abstract

We report on two new physiological phenomena: the long-term and total heart rate asymmetry, which describe a significantly larger contribution of heart rate accelerations to long-term and total heart rate variability. In addition to the existing pair of indices, {text {SD1}}_{rm d}, {text {SD1}}_{rm a}, which are based on partitioning short-term variance, we introduce two other pairs of descriptors based on partitioning long-term ({text {SD2}}_{rm d}, {text {SD2}}_{rm a}) and total ( {text {SDNN}}_{rm d}, {text {SDNN}}_{rm a}) heart rate variability. The new asymmetric descriptors are used to analyze RR intervals time series derived from the 30-min ECG recordings of 241 healthy subjects resting in supine position. It is shown that both new types of asymmetry are present in 76% of the subjects. The new phenomena reported here are real physiological findings rather than artifacts of the method since they vanish after data shuffling.