Is the algorithm used to process heart rate variability data clinically relevant? Analysis in male adolescents

ABSTRACT Objective To analyze whether the algorithm used for the heart rate variability assessment (fast Fourier transform versus autoregressive methods) influenced its association with cardiovascular risk factors in male adolescents. Methods This cross-sectional study included 1,152 male adolescents (aged 14 to 19 years). The low frequency, high frequency components (absolute numbers and normalized units), low frequency/high frequency ratio, and total power of heart rate variability parameters were obtained using the fast Fourier transform and autoregressive methods, while the adolescents were resting in a supine position. Results All heart rate variability parameters calculated from both methods were different (p<0.05). However, a low effect size (<0.1) was found for all parameters. The intra-class correlation between methods ranged from 0.96 to 0.99, whereas the variation coefficient ranged from 7.4 to 14.8%. Furthermore, waist circumference was negatively associated with high frequency, and positively associated with low frequency and sympatovagal balance (p<0.001 for both fast Fourier transform and autoregressive methods in all associations). Systolic blood pressure was negatively associated with total power and high frequency, whereas it was positively associated with low frequency and sympatovagal balance (p<0.001 for both fast Fourier transform and autoregressive methods in all associations). Body mass index was negatively associated with high frequency, while it was positively associated with low frequency and sympatovagal balance (p values ranged from <0.001 to 0.007). Conclusion There are significant differences in heart rate variability parameters obtained with the fast Fourier transform and autoregressive methods in male adolescent; however, these differences are not clinically significant.

摘要
研究目的：分析用于心率变异性（Heart Rate Variability, HRV）评估的两种方法——快速傅里叶变换（Fast Fourier Transform, FFT）与自回归方法（Autoregressive Methods）——是否会影响其与男性青少年心血管危险因素的相关性。

研究方法：本项横断面研究共纳入1152名年龄介于14至19岁的男性青少年。受试者取仰卧位静息状态时，分别采用快速傅里叶变换与自回归方法计算心率变异性参数，包括低频、高频分量（绝对值与标准化单位值）、低频/高频比值以及总功率。

研究结果：两种方法计算得到的全部心率变异性参数均存在统计学差异（p<0.05）。但所有参数的效应量均较小（<0.1）。两种方法的组内相关系数介于0.96至0.99之间，变异系数则介于7.4%至14.8%之间。进一步分析显示，腰围与高频分量呈负相关，与低频分量及交感迷走平衡（sympatovagal balance）呈正相关（快速傅里叶变换与自回归方法的所有关联均满足p<0.001）。收缩压与总功率及高频分量呈负相关，与低频分量及交感迷走平衡呈正相关（两种方法的所有关联均满足p<0.001）。体质量指数与高频分量呈负相关，与低频分量及交感迷走平衡呈正相关（p值范围为<0.001至0.007）。

研究结论：针对男性青少年群体，快速傅里叶变换与自回归方法得到的心率变异性参数存在显著统计学差异，但此类差异不具有临床意义。