Analysis of oscillatory processes in the cardiovascular system in response to local heating in patients with type 2 diabetes mellitus

Abstract

A comprehensive spectral analysis was used to assess heart rate variability and skin perfusion pattern of limbs in patients with type 2 diabetes mellitus in response to local heating and to identify significant predictors of physiological and pathological changes in the cardiovascular system. An electrocardiogram and skin perfusion on the forearm and foot were measured using Laser Doppler flowmetry at rest and during local heating in both healthy volunteers and patients with type 2 diabetes. The wavelet analysis was applied to Laser Doppler signals and heart rate variability (based on electrocardiogram signals). ROC analysis was used to evaluate significant predictors. The analysis results of patients with type 2 diabetes were compared with healthy controls. The following changes were observed in patients 1) impairment of skin blood flow reserve on the foot during heating, 2) lower amplitude oscillations in heart rate at rest and during heating, 3) an increase in amplitude of oscillations in the skin blood flow from the forearm in intervals related to respiration and heart activity at rest and during heating, 4) a decrease in amplitude of oscillations in the skin blood flow on the foot in the interval related to myogenic activity at rest and in cardiointerval during heating. The parameters of cardiovascular system (energies of heart rate variability at low-frequencies recorded by laser Doppler flowmetry on forearm in intervals related to respiration activity) with high discriminative power were revealed to distinguish patients from healthy subjects in response to local heating; these parameters can be used as markers for early diagnosis of microvascular disorders.