Table 1 Description of HRV parameters used in this study.
No | Parameters | Unit | Description |
|---|---|---|---|
Time domain parameters | |||
1 | meanRR | ms | The mean of RR intervals |
2 | meanHR | beats/min | The mean heart rate |
3 | SDNN | ms | Standard deviation of RR intervals |
4 | RMSSD | ms | Square root of the mean squared differences between successive RR intervals |
5 | SDSD | ms | Standard deviation of the difference between adjacent interval |
6 | CV | – | Ratio between SDNN and RR band powers |
7 | PNN20 | % | NN20 divided by the total number of RR intervals |
8 | PNN50 | % | NN50 divided by the total number of RR intervals |
Frequency domain parameters | |||
1 | VLF percent | % | Relative powers in very low frequency band (0–0.04 Hz) |
2 | LF percent | % | Relative powers low frequency band (0.04–0.15 Hz) |
3 | HF percent | % | Relative powers in high frequency band (0.15–0.4 Hz) |
4 | LF norm | – | Normalized low frequency power |
5 | HF norm | – | Normalized high frequency power |
6 | LF/HF | – | Ratio of LF power to HF power |
Nonlinear parameters | |||
1 | SD1 | ms | Standard deviation for T direction of Poincare plot |
2 | SD2 | ms | Standard deviation for L direction of Poincare plot |
3 | SD1/SD2 | – | Ratio of SD1 to SD2 |
4 | SampleEn | – | A method to measure the complexity of time series |
