Correlation of electrocardiographic measurements of HRV from 1 min to 5 min recordings
| 1 min | 5 min | ICC | 95% CI | |||
| Mean | SD | Mean | SD | |||
| Maximal RR (ms) | 1050.9 | 176.55 | 1095.2 | 176.55 | 0.986* | 0.979 to 0.990 |
| Minimal RR (ms) | 897.9 | 139.76 | 838.9 | 139.76 | 0.951* | 0.928 to 0.967 |
| Average RR (ms) | 972.4 | 154.96 | 970.2 | 154.96 | 0.998* | 0.997 to 0.999 |
| Average HR (bpm) | 63.1 | 10.91 | 63.0 | 10.91 | 0.995* | 0.993 to 0.997 |
| SDNN (ms) | 34.0 | 24.18 | 41.1 | 24.18 | 0.973* | 0.960 to 0.982 |
| RMSSD (ms) | 32.5 | 29.98 | 34.3 | 29.98 | 0.992* | 0.988 to 0.995 |
| HRV-TI | 7.9 | 2.53 | 12.2 | 2.53 | 0.786 | 0.683 to 0.855 |
| NN50 | 28 | 4.12 | 14.9 | 4.12 | 0.542 | 0.323 to 0.691 |
| pNN50 | 2.0 | 3.05 | 5.2 | 3.05 | 0.785 | 0.682 to 0.855 |
| VLF (ms2) | 167.8 | 109.11 | 220.2 | 109.11 | 0.656 | 0.490 to 0.767 |
| LF (ms2) | 160.2 | 89.65 | 136.7 | 89.65 | 0.726 | 0.594 to 0.815 |
| HF (ms2) | 161.9 | 92.42 | 112.7 | 92.42 | 0.832 | 0.751 to 0.886 |
| Total power (ms2) | 495.6 | 101.01 | 520.4 | 101.01 | 0.863 | 0.798 to 0.908 |
| LF/HF | 1.7 | 2.07 | 1.8 | 2.07 | 0.85 | 0.777 to 0.898 |
| Ln(SDNN) | 3.351 | 0.560 | 3.584 | 0.489 | 0.947* | 0.922 to 0.964 |
| Ln(RMSSD) | 3.230 | 0.664 | 3.310 | 0.614 | 0.981* | 0.972 to 0.987 |
| Ln(HRV-TI) | 2.019 | 0.322 | 2.421 | 0.397 | 0.9* | 0.853 to 0.933 |
| Ln(VLF) | 4.853 | 0.836 | 5.311 | 0.455 | 0.634 | 0.459 to 0.753 |
| Ln(LF) | 4.923 | 0.571 | 4.820 | 0.465 | 0.88 | 0.823 to 0.919 |
| Ln(HF) | 4.883 | 0.697 | 4.552 | 0.617 | 0.874 | 0.813 to 0.915 |
| Ln(total power) | 6.172 | 0.316 | 6.241 | 0.169 | 0.648 | 0.478 to 0.762 |
| Ln(LF/HF) | 0.041 | 0.981 | 0.268 | 0.823 | 0.88 | 0.823 to 0.919 |
Correlation of 1 min and 5 min electrocardiographic HRV measurements.
*Excellent correlation.
HF, high frequency components; HRV, heart rate variability; HRV-TI, HRV-triangular index; ICC, intraclass correlation; LF, low frequency components; NN50, number of intervals differing by >50 ms from preceding interval; pNN50, NN50 divided by total number of intervals; RMSSD, root mean square of successive differences in RR intervals; SDNN, SD of RR interval; VLF, very low-frequency components.