Is 50 Hz high enough ECG sampling frequency for accurate HRV analysis?

Abstract

With the worldwide growth of mobile wireless technologies, healthcare services can be provided at anytime and anywhere. Usage of wearable wireless physiological monitoring system has been extensively increasing during the last decade. These mobile devices can continuously measure e.g. the heart activity and wirelessly transfer the data to the mobile phone of the patient. One of the significant restrictions for these devices is usage of energy, which leads to requiring low sampling rate. This article is presented in order to investigate the lowest adequate sampling frequency of ECG signal, for achieving accurate enough time domain heart rate variability (HRV) parameters. For this purpose the ECG signals originally measured with high 5 kHz sampling rate were down-sampled to simulate the measurement with lower sampling rate. Down-sampling loses information, decreases temporal accuracy, which was then restored by interpolating the signals to their original sampling rates. The HRV parameters obtained from the ECG signals with lower sampling rates were compared. The results represent that even when the sampling rate of ECG signal is equal to 50 Hz, the HRV parameters are almost accurate with a reasonable error.

Smart Device for the Determination of Heart Rate Variability in Real Time

“…This device allows up to 16-channel 10-bit ADC, with a maximum sampling rate of 1000 ksps. Although it was shown that a sampling rate as low as 50 Hz could be used to measure the ECG signal without compromising the accuracy of the calculated time domain HRV parameters [32], other studies recommend the frequency of 200 Hz to avoid possible distortions in the frequency spectrum of the signal [33], the basis of the analysis shown in the present work. For this reason, a sampling frequency of 200 Hz was selected as the working frequency of the device, to minimize computational load and energy consumption, while ensuring a quality in the results after processing.…”

Enhancing the Robustness of Smartphone Photoplethysmography: A Signal Quality Index Approach

“…Fourth, the sampling rate has a significant influence on the accuracy of HRV measures. Although there have been many different suggestions for the minimum sampling rate (ranging from 25 Hz [42] to 125 Hz [43] in PPG studies and 50 Hz [71] to 1000 Hz [72] in ECG studies), most smartphone cameras sample at about 30 Hz, which is below the level of most suggestions. Therefore, the poor measuring quality caused by low frame rates is generally considered a potential challenge to the validity of using the smartphone PPG method.…”

Task-induced deactivation in diverse brain systems correlates with interindividual differences in distinct autonomic indices

“…Specifically, A low sampling rate reduces the accuracy in the detection of the fiducial points of cardiac events, which may cause changes in the subsequent derived autonomic indices. However, although sampling rate impacts the accuracy of HRV indices (Garcia-Gonzalez, Fernandez-Chimeno, & Ramos-Castro, 2004), traditional time, frequency and nonlinear indexes can be computed with a reasonable estimation error for low ECG sampling rates (Voss, Wessel, Sander, Malberg, & Dietz, 1996;Ziemssen, Gasch, & Ruediger, 2008), and even a sampling rate as low as 50 Hz can be used without irreparably degrading accuracy (Mahdiani, Jeyhani, Peltokangas, & Vehkaoja, 2015). Importantly, when we interpolated the PPG signal to a higher frequency, and recalculated RMSSD based on re-estimated peak locations, we found that the resulting RMSSD values were highly correlated with the original calculations suggesting that very similar BRAIN/ANS correlations would maintain under a higher sampling rate.…”