Table 2.
Kubios HRV features derived from Apple Watch ECG.
| Name | Description |
|---|---|
| ECG_Mean HR | Mean of heart rate from ECG(ms) |
| ECG_ SD HR | Standard deviation of instantaneous heart rate from ECG (1/min) |
| ECG_Min HR | Minimum instantaneous heart rate calculated using 5 beat moving average from ECG(1/min) |
| ECG_Max HR | Maximum instantaneous heart rate calculated using 5 beat moving average from ECG (1/min) |
| HRV-1 | Heart rate variability collected as SDNN with the Apple Watch |
| ECG_PNS Index | Parasympathetic nervous system activity compared to normal resting values |
| ECG_SNS Index | Sympathetic nervous system activity compared to normal resting values |
| ECG_Stress Index | Square root of Baevsky’s stress index |
| ECG_Mean RR | Mean of R-R intervals (ms) |
| ECG_SDNN | Standard deviation of R-R intervals (ms) |
| ECG_RMSSD | Square root of the mean squared differences between successive RR intervals f(ms) |
| ECG_DC | Heart rate deceleration capacity (ms) |
| ECG_DCMod | Modified DC computer as a two-point difference (ms) |
| ECG_AC | Heart rate acceleration capacity (ms) |
| ECG_ACMod | Modified AC computer as a two-point difference (ms) |
| ECG_FFT LF | Fast Fourier Transform Low Frequency band components (Hz) |
| ECG_FFT HF | Fast Fourier Transform High Frequency band components (Hz) |
| ECG_AR LF | Autoregressive Low Frequency band components (Hz) |
| ECG_AR HF | Autoregressive High Frequency band components (Hz) |
| ECG_FFT Absolute Power LF | Fast Fourier Transform Absolute Power of Low Frequency band components (ms2) |
| ECG_FFT Absolute Power HF | Fast Fourier Transform Absolute Power of High Frequency band components (ms2) |
| ECG_AR Absolute Power LF | Autoregressive Absolute Power of Low Frequency band components (ms2) |
| ECG_AR Absolute Power HF | Autoregressive Absolute Power of High Frequency band components (ms2) |
| ECG_FFT Relative Power LF | Fast Fourier Transform Relative Power of Low Frequency band components (%) |
| ECG_FFT Relative Power HF | Fast Fourier Transform Relative Power of High Frequency band components (%) |
| ECG_AR Relative Power LF | Autoregressive Relative Power of Low Frequency band components (%) |
| ECG_AR Relative Power HF | Autoregressive Relative Power of High Frequency band components (%) |
| ECG_FFT Normalized Power LF | Fast Fourier Transform Normalized Power of Low Frequency band components (n.u) |
| ECG_FFT Normalized Power HF | Fast Fourier Transform Normalized Power of High Frequency band components (n.u) |
| ECG_FFT Total Power | Fast Fourier Transform Total Power (ms2) |
| ECG_FFT LF/HF | Fast Fourier Transform ratio between low and high frequency |
| ECG_AR Normalized Power LF | Autoregressive Normalized Power of Low Frequency band components (n.u) |
| ECG_AR Normalized Power HF | Autoregressive Normalized Power of High Frequency band components (n.u) |
| ECG_AR Total Power | Autoregressive Total Power (ms2) |
| ECG_AR LF/HF | Autoregressive ratio between low and high frequency |
| ECG_SD1 | The standard deviation perpendicular to the line-of-identity in Poincaré plot (ms) |
| ECG_SD2 | The standard deviation along the line-of-identity in Poincaré plot (ms) |
| ECG_SD2/SD1 | Ratio between SD2 and SD1 (ms) |