Heart rate variability: comparison among devices with different temporal resolutions

Several devices based on ECG can acquire beat-to-beat intervals, and some of these devices may be used for heart rate variability (HRV) analysis. Most of these devices and their methods to acquire the beat-to-beat intervals need to be validated for HRV analysis by comparing them against traditional methods. Some of these methods have low temporal resolution, which may be sufficient for certain studies. HRV analysis parameters obtained from two methods differing in temporal resolution were compared to the HRV analysis parameters obtained from a referent method (ECG). One of the methods had a high resolution (<1 ms) and the other method had a low resolution (10 ms). Seven healthy male volunteers participated in the study. The beat-to-beat intervals were collected simultaneously from the three methods and the HRV parameters derived from them were used for our comparisons. The Pearson product-moment correlations were used, which demonstrated an excellent correlation (r > 0.99) in time domain, frequency domain and some non-linear HRV measures. The HRV measures were further analyzed using the one-way repeated-measures analysis of variance (ANOVA) and statistically significant differences were observed in some of the HRV parameters obtained from the low-resolution method, especially the mean RR (p < 0.001) and the mean heart rate (p < 0.001). Since the same software was used for HRV analysis of the three methods, any differences were due to the temporal resolution of the RR intervals measured by the methods. Overall, both the methods correlated very well with the referent method among healthy volunteers in resting conditions and may be used by researchers for HRV studies.