Background: Impaired Baroreflex sensitivity (BRS) may indicate cardiovascular autonomic neuropathy (CAN), which often remains undiagnosed during the initial course of diabetes mellitus. The baroreflex mechanism can be considered negative feedback because of baroreflex delay, the time delay between a change in blood pressure, and the counteracting heart rate response. This work sought to analyze BRS through the sequence method, but establishing delays in checking the RR interval, from 1 to 10 RR intervals lag after systolic blood pressure change. We hypothesized that diabetic patients with subclinical CAN would have a detectable delay in autonomic nervous system activity and that it would differ from other patients.
Results: The study included 30 subjects with diabetes mellitus. Eleven patients had established CAN (mean ± SD age 37 ± 8 years), 9 patients had subclinical CAN (age 35 ± 10 years), and 10 patients did not have CAN (age 35 ± 6 years). Indexes related to the delay in response of the BRS were proposed and obtained. The three variables that showed potential to separate patients with and without CAN were highest BRS index, BRS with the largest number of sequences, and lag of the largest number of sequences. Several variables were observed to distinguish between individuals with subclinical and established CAN, including the number of sequences of the highest BRS, lag of the highest BRS, and the highest number of sequences.
Conclusions: Thus, analysis of BRS and the reaction delay in the heart rate variability signal may contribute to the detection of CAN in its asymptomatic stage.