In the CACPR 2021 Annual Meeting Abstracts1 published in the July 2021 issue of the journal, one abstract was supposed to be replaced with an updated version but was accidentally removed entirely from the issue. The full abstract is included here:

Title: Association Between Functional Capacity, and Heart Rate Variability in Subjects with Type 2 Diabetes

Authors: Gabriela do Nascimento Cândido1; Mariana Balbi Seixas2; Gabriel Luiz Leite de Almeida2; Lilian Pinto da Silva2; Raquel Rodrigues Britto1

Institution(s):1Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. 2Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil.

Background: Although heart rate variability (HRV) is not routinely measured as part of the management of type 2 diabetes (T2DM), autonomic nervous system impairment may occur even in the early years of diabetes. HRV is a measure of the modulation of the autonomic nervous system over the heart and reflects cardiovascular health since high overall HRV indices indicate good cardiac autonomic control. Low overall HRV is associated with poor functional capacity and increased risk of death. Since HRV measures are reduced in people with T2DM, we hypothesized an association between these measures and functional capacity.

Objective: We sought to investigate the relationship between functional capacity and HRV in subjects with type 2 diabetes.

Methods: Cross-sectional observational study using data from the baseline of the randomized clinical trial (RCT) Diabetes College Brazil Study (NCT03914924) collected until March 2020. The participants were submitted to a 10-minute rest heartbeat collection by a heart rate monitor (V800, Polar®, Kempele, Finland) to later HRV indices calculation using the Kubios HRV software. The HRV indices calculated included non-linear indices [standard deviations of the Poincare' plot (SD1, SD2), sample entropy (SampEn), approximate entropy (ApEn), (short-term α1 and long-term α2 scaling exponents from detrended fluctuation analysis (DFA)]. Also, linear indices obtained in time-domain [standard deviation of normal heartbeats (SDNN), root mean square of successive normal heartbeats differences (RMSSD) and percentage of successive normal heartbeats that differ by more than 50ms (pNN50)] and frequency-domain [low frequency (LF) and high frequency (HF) components from spectral analysis in absolute (ms2) and normalized units (nu), and LF/HF ratio]. Besides, the functional capacity was assessed by the distance covered in the incremental shuttle walking test (ISWT). Spearman's correlation test was used, considering P < 0.05 as significant.

Results: Twenty-six subjects (60 ± 6 years and 15 female) with T2DM were included in this study. A positive and significant correlation was found between the ISWT distance and LF ms2 (r = 0.522; P = 0.006) and HF ms2 (r =0.400; P =0.043), without significant correlation with the others HRV indices calculated in this study.

Conclusion: These preliminary results showed that functional capacity is positively associated with HRV indices that reflect overall HRV (LF ms2) and parasympathetic modulation (HF ms2). Therefore, a greater functional capacity is related to better cardiac autonomic modulation.