Table 2.
Time domain HRV analysis (n = 40).
| HRV Indices | Mean | SD | Median | Lower one-third | Upper one-third |
|---|---|---|---|---|---|
| Mean NN (ms) | 733.58 | 136.04 | 712.50 | 669.00 | 788.54 |
| SDNN (ms) | 14.30 | 7.68 | 15.00 | 10.06 | 17.06 |
| RMSSD (ms) | 11.65 | 7.88 | 10.50 | 6.53 | 15.06 |
| TINN (ms) | 76.65 | 28.41 | 78.00 | 63.00 | 94.00 |
| NN50 | 2.45 | 5.34 | 0.00 | 0.00 | 0.00 |
| pNN50 (%) | 0.63 | 1.33 | 0.00 | 0.00 | 0.00 |
HRV: heart rate variability, SD: standard deviation, NN: normal-to-normal interval, SDNN: standard deviation of normal-to-normal interval, RMSSD: root mean square standard deviation of normal-to-normal interval, TINN: triangular interpolation of normal-to-normal interval histogram, NN50: number of pairs of adjacent normal-to-normal intervals differing by more than 50 ms, and pNN50: the proportion of NN50 divided by total normal-to-normal intervals.