Geometric indexes of heart rate of variability identifies autonomic alterations in young patients with type 1 diabetes mellitus

Author(s): Naiara Maria Souza*, Calos Marcelo Pastre, Anne Kastelianne França da Silva, Aline Fernanda Barbosa Bernardo, Franciele Marques Vanderlei, Talys Naomi Harada Bonora, Francis Lopes Pacagnelli, Gustavo Carvalho Machado and Luiz Carlos Marques Vanderlei

Objectives: To compare autonomic modulation in young patients with type 1 diabetes mellitus (DM1) (n=20) and healthy control subjects (n=23) using geometric indexes of heart rate variability (HRV) associated with linear domains of time and frequency; and to verify correlations between geometric indexes and those obtained by the time and the frequency domain of diabetic individuals.
Methods: Heart rate was recorded as beat-to-beat with subjects supine for 30 min. The following indexes were calculated: RRtri, TINN, Poincaré plot, SD1, SD2, SD1/SD2, RMSSD, SDNN, LF and HF (ms²/un) and LF/HF. Visual analysis of the Poincaré plot was also performed. Independent Student’s t test or Mann-Whitney test, and Spearman’s correlation test or Pearson’s correlation test were used for statistical analysis.
Results: Significantly lower values of SD1, SD2, RRtri, RMSSD, SDNN, and LF and HF in ms² were observed in patients with DM1 compared with healthy subjects.
Conclusion: The Poincaré plot showed less dispersion of RR intervals for the DM1 group. Strong correlations were observed with the geometric indexes with the time domain and frequency indexes.

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