Recurrence Quantification Analysis of Heart Rate Variability in Early Diagnosis of Diabetic Autonomic Neuropathy
Abstract
Introduction: Detection of autonomic dysfunction in subclinical stages of diabetic cardiovascular autonomic neuropathy is highly important and helps in therapeutic management. Evaluation of cardiovascular function is usually based on heart rate variability (HRV) linear data analysis in time and frequency domains.
However, autonomic control of heart rate is complex and could be described by non-linear analysis. In our study, non-linear recurrence quantification analysis (RQA) was used.
Methods: We analyzed RQA during orthostatic test in 20 patients with type 2 diabetes (mean age 54 years). Results were compared to sex and age-matched group of 20 healthy controls (mean age 53 years).
Cross-comparison between RQA, time- and frequency-domains analysis during the supine rest phase of orthostatic test was also performed. Results: There was significant increase in percentage of recurrences in diabetic patients compared to controls in the following variables: determinism (p<0.0001), laminarity (p<0.0002), length of the longest diagonal line Lmax (p=0.026) and mean length of vertical lines trapping time (p=0.0214) in both phases of the orthostatic test.
We found significant increase in determinism, laminarity and trapping time in the supine rest phase. However, the Lmax parameter remained insignificant compared to the control group and results were similar to previous studies.
Conclusion: Reduction of complexity in cardiovascular regulation was found in diabetic patients compared to age-matched controls. In comparison to standard methods, RQA appears to be more sensitive in diagnostics of subclinical cardiovascular autonomic neuropathy.
RQA may be useful as an additional approach to time and frequency domain analysis of HRV.