Table 2 List of HRV features.
From: Preterm birth risk stratification through longitudinal heart rate and HRV monitoring in daily life
Category | Feature | Units | Description |
|---|---|---|---|
Time-domain | AVNN | ms | Average of NN intervals |
SDNN | ms | Standard deviation of NN intervals | |
RMSSD | ms | Root mean square of successive NN interval differences | |
pNN50 | % | Percentage of successive NN intervals that differ by more than 50 ms | |
Frequency-domain | LF | \(s^2\) | Spectral power of low frequencies (0.04-0.15 Hz) |
HF | \(s^2\) | Spectral power of high frequencies (0.15-0.4 Hz) | |
LFHF | % | LF to HF ratio | |
Non-linear | SD1 | ms | Standard deviation of Poincaré plot perpendicular to the line-of-identity |
SD2 | ms | Standard deviation of the Poincaré plot along the line-of-identity | |
SD1SD2 | % | SD1 to SD2 ratio |
