Rogers Bruce, Mourot Laurent, Gronwald Thomas
College of Medicine, University of Central Florida, 6850 Lake Nona Boulevard, Orlando, FL 32827-7408, USA.
EA3920 Prognostic Factors and Regulatory Factors of Cardiac and Vascular Pathologies, Exercise Performance Health Innovation (EPHI) Platform, University of Bourgogne Franche-Comté, 21000 Besançon, France.
J Clin Med. 2021 Sep 9;10(18):4075. doi: 10.3390/jcm10184075.
An index of heart rate (HR) variability correlation properties, the short-term scaling exponent alpha1 of detrended fluctuation analysis (DFA a1) has shown potential to delineate the first ventilatory threshold (VT1). This study aims to extend this concept to a group of participants with cardiac disease. Sixteen volunteers with stable coronary disease or heart failure performed an incremental cycling ramp to exhaustion PRE and POST a 3-week training intervention. Oxygen uptake (VO) and HR at VT1 were obtained from a metabolic cart. An ECG was processed for DFA a1 and HR. The HR variability threshold (HRVT) was defined as the VO, HR or power where DFA a1 reached a value of 0.75. Mean VT1 was reached at 16.82 ± 5.72 mL/kg/min, HR of 91.3 ± 11.9 bpm and power of 67.8 ± 17.9 watts compared to HRVT at 18.02 ± 7.74 mL/kg/min, HR of 94.7 ± 14.2 bpm and power of 73.2 ± 25.0 watts. Linear relationships were seen between modalities, with Pearson's r of 0.95 (VO), 0.86 (HR) and 0.87 (power). Bland-Altman assessment showed mean differences of 1.20 mL/kg/min, 3.4 bpm and 5.4 watts. Mean peak VO and VT1 did not change after training intervention. However, the correlation between PRE to POST change in VO at VT1 with the change in VO at HRVT was significant (r = 0.84, < 0.001). Reaching a DFA a1 of 0.75 was associated with the VT1 in a population with cardiac disease. VT1 change after training intervention followed that of the HRVT, confirming the relationship between these parameters.
心率（HR）变异性相关属性指标，即去趋势波动分析（DFA）的短期标度指数α1，已显示出描绘第一通气阈值（VT1）的潜力。本研究旨在将这一概念扩展至一组患有心脏病的参与者。16名患有稳定型冠心病或心力衰竭的志愿者在为期3周的训练干预前后进行了递增式自行车运动直至力竭。通过代谢车获取VT1时的摄氧量（VO）和心率。对心电图进行处理以获取DFAα1和心率。心率变异性阈值（HRVT）定义为DFAα1达到0.75时的VO、心率或功率。与HRVT时的18.02±7.74 mL/kg/min、心率94.7±14.2次/分钟和功率73.2±25.0瓦相比，达到VT1时的平均VO为16.82±5.72 mL/kg/min、心率为91.3±11.9次/分钟、功率为67.8±17.9瓦。各指标之间呈现线性关系，VO的皮尔逊相关系数r为0.95，心率为0.86，功率为0.87。布兰德 - 奥特曼评估显示平均差异分别为1.20 mL/kg/min、3.4次/分钟和5.4瓦。训练干预后，平均峰值VO和VT1未发生变化。然而，VT1时VO的训练前至训练后变化与HRVT时VO的变化之间存在显著相关性（r = 0.84，P < 0.001）。在患有心脏病的人群中，DFAα1达到0.75与VT1相关。训练干预后VT1的变化与HRVT的变化一致，证实了这些参数之间的关系。
