衰弱与心脏自主神经控制受损：传统心率变异性指标主成分聚合的新见解
Frailty and impaired cardiac autonomic control: new insights from principal components aggregation of traditional heart rate variability indices.
作者信息
Varadhan Ravi, Chaves Paulo H M, Lipsitz Lewis A, Stein Phyllis K, Tian Jing, Windham B Gwen, Berger Ronald D, Fried Linda P
机构信息
The Center on Aging and Health, Johns Hopkins University, Baltimore, Maryland, USA.
出版信息
J Gerontol A Biol Sci Med Sci. 2009 Jun;64(6):682-7. doi: 10.1093/gerona/glp013. Epub 2009 Feb 17.
BACKGROUND
Age-related deterioration in homeostatic regulatory mechanisms leads to decreased complexity in their output. For example, the degradation of cardiac autonomic control results in loss of complexity in the heart rate signal. Frailty is a state of critically impaired homeostasis that results in heightened vulnerability to stressors. We propose a new measure of heart rate variability (HRV) to capture the impairment in cardiac autonomic control associated with frailty.
METHODS
Traditional time and frequency domain indices of HRV were obtained from 2-hour ambulatory electrocardiograms (ECGs) of 276 women (65-101 years old) in the Women's Health and Aging Study-I. Principal components analysis was conducted on the correlation matrix of HRV indices. Frailty was defined using a validated instrument. Regression models were used to evaluate associations of HRV measures with age, frailty, and 5-year mortality.
RESULTS
The first two principal components (PCs), PC1 and PC2, explained 90% of the variance in HRV indices. PC1 is the mean of log-transformed HRV indices. PC2 is a linear combination of log-transformed indices, with positive weights for very low frequency (VLF), low frequency (LF), and standard deviation of N-N intervals (SDNN), and negative weights for high frequency (HF), root-mean-squared differences of successive N-N intervals (RMSSD), and proportion of all N-N intervals that are larger than 50 ms (pNN50). Decreases in SDNN, VLF, LF, and LF/HF were associated with an increased risk of frailty. PC2 was more strongly associated with age (beta = -.23, p < .001) and frailty (beta = -.73, p < 10(-5)) than were the individual HRV indices and LF/HF. PC2 was also the best predictor of 5-year mortality (beta = -.60, p < 10(-6)).
CONCLUSIONS
Cardiac autonomic control, as reflected by HRV, is impaired in frailty. A new measure derived from PC aggregation of traditional HRV indices provides a compact summary of this impairment.
背景
与年龄相关的稳态调节机制退化导致其输出的复杂性降低。例如，心脏自主神经控制的退化导致心率信号复杂性的丧失。衰弱是一种稳态严重受损的状态，会导致对压力源的易感性增加。我们提出了一种新的心率变异性（HRV）测量方法，以捕捉与衰弱相关的心脏自主神经控制受损情况。
方法
从女性健康与衰老研究-I中276名年龄在65至101岁之间的女性的2小时动态心电图（ECG）中获取传统的HRV时域和频域指标。对HRV指标的相关矩阵进行主成分分析。使用经过验证的工具定义衰弱。回归模型用于评估HRV测量值与年龄、衰弱和5年死亡率之间的关联。
结果
前两个主成分（PC），即PC1和PC2，解释了HRV指标中90%的方差。PC1是对数转换后的HRV指标的平均值。PC2是对数转换指标的线性组合，对极低频（VLF）、低频（LF）和N-N间期标准差（SDNN）赋予正权重，对高频（HF）、连续N-N间期的均方根差（RMSSD）以及所有大于50毫秒的N-N间期比例（pNN50）赋予负权重。SDNN、VLF、LF和LF/HF的降低与衰弱风险增加相关。与个体HRV指标和LF/HF相比，PC2与年龄（β = -0.23，p < 0.001）和衰弱（β = -0.73，p < 10⁻⁵）的相关性更强。PC2也是5年死亡率的最佳预测指标（β = -0.60，p < 10⁻⁶）。
结论
HRV反映的心脏自主神经控制在衰弱中受损。从传统HRV指标的主成分聚合中得出的一种新测量方法提供了这种损伤的简洁总结。
Zotero 插件