Yanagisawa Naotake, Yao Bingwei, Zhang Jianting, Nishizaki Yuji, Kasai Takatoshi
Medical Technology Innovation Center, Juntendo University, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
E3 Enterprise, 32nd Floor, Shinjuku Nomura Building, 1-26-2 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan.
Heart Vessels. 2024 Dec 13. doi: 10.1007/s00380-024-02506-2.
Ballistocardiogram (BCG) captures minute vibrations generated by heart movements. These vibrations are converted into heart rate variability (HRV) indices, allowing their unobtrusive monitoring over extended periods, while reducing the burden on patients or subjects. In this study, to evaluate the agreement between the HRV indices, we compared the HRV indices estimated from the BCG device with those obtained from the gold standard electrocardiogram (ECG). Twenty-five healthy volunteers (mean age: 40.6 ± 12.8 years; 14 males and 11 females) rested in the supine position on a bed with a BCG device placed under a pillow while ECG electrodes were attached. BCG and ECG measurements were simultaneously recorded for 20 min. Five min of time-series data for the JJ and RR intervals obtained from BCG and ECG were converted into HRV indices. These indices included the time-domain measures (mean inter-beat intervals [IBIs], standard deviation of normal-to-normal intervals [SDNN], root mean square of successive differences [RMSSD], and percent of difference between adjacent normal RR intervals greater than 50 ms [pNN50]) and frequency-domain measures (normalized low-frequency [LF], high-frequency power [HF], and LF/HF ratio). Of the 25 individuals, data of 22 (mean age: 38.9 ± 12.3 years; 13 males and 9 females) were used to assess the agreement between the two methods, excluding 3 (1 male and 2 females) with frequent premature ventricular contractions observed on ECG. Correlations between measurements were examined using scatter plots and Pearson's product-moment correlation coefficients; in contrast, differences between measurements were evaluated using paired t-tests. The Bland-Altman analysis was used to assess the agreement. For the mean IBIs, the correlation coefficient was 0.999 (p < 0.001), and the limits of agreement ranged from - 8.35 to 11.70, with no evidence of fixed bias (p = 0.139) or proportional bias (p = 0.402), indicating excellent agreement. In contrast, the correlation coefficients for SDNN, RMSSD, and pNN50 were 0.931 (p < 0.001), 0.923 (p < 0.001), and 0.964 (p < 0.001), respectively, showing high correlations. However, a fixed bias was observed in RMSSD (p = 0.007) and pNN50 (p = 0.010), and a proportional bias in SDNN (p = 0.002). The correlation coefficients for LF, HF, and LF/HF ratio were approximately 0.7, indicating lower agreement owing to observed fixed and proportional biases. These results indicate that, while the degree of agreement varies among HRV indices, the JJ intervals measured from BCG can be used as a suitable alternative to the RR intervals from ECG.
心冲击图（BCG）可捕捉心脏运动产生的微小振动。这些振动被转换为心率变异性（HRV）指标，从而能够在较长时间内对其进行无创监测，同时减轻患者或受试者的负担。在本研究中，为评估HRV指标之间的一致性，我们将BCG设备估算的HRV指标与通过金标准心电图（ECG）获得的指标进行了比较。25名健康志愿者（平均年龄：40.6±12.8岁；14名男性和11名女性）仰卧在床上，枕头下放置BCG设备，同时连接ECG电极。BCG和ECG测量同时记录20分钟。从BCG和ECG获得的JJ和RR间期的5分钟时间序列数据被转换为HRV指标。这些指标包括时域测量值（平均心跳间期[IBIs]、正常到正常间期的标准差[SDNN]、连续差值的均方根[RMSSD]以及相邻正常RR间期差值大于50毫秒的百分比[pNN50]）和频域测量值（归一化低频[LF]、高频功率[HF]以及LF/HF比值）。在这25名个体中，22名（平均年龄：38.9±12.3岁；13名男性和9名女性）的数据用于评估两种方法之间的一致性，排除了3名（1名男性和2名女性）在ECG上观察到频繁室性早搏的个体。测量值之间的相关性通过散点图和Pearson积矩相关系数进行检验；相反，测量值之间的差异使用配对t检验进行评估。采用Bland-Altman分析来评估一致性。对于平均IBIs，相关系数为0.999（p<0.001），一致性界限范围为-8.35至11.70，没有固定偏差（p=0.139）或比例偏差（p=0.402）的证据，表明一致性极佳。相比之下，SDNN、RMSSD和pNN50的相关系数分别为0.931（p<0.001）、0.923（p<0.001）和0.964（p<0.001），显示出高度相关性。然而，在RMSSD（p=0.007）和pNN50（p=0.010）中观察到固定偏差，在SDNN（p=0.002）中观察到比例偏差。LF、HF和LF/HF比值的相关系数约为0.7，由于观察到固定和比例偏差，表明一致性较低。这些结果表明，虽然HRV指标之间的一致程度有所不同，但从BCG测量的JJ间期可作为ECG的RR间期的合适替代指标。
