Table 2.
Standardized differences (95% CI) of time-domain and frequency-domain heart rate variability parameters in different time segments of the electrocardiogram and Pulse Express PRO measurements compared with the 0-5–minute standarda.
| Device and time segment (minutes) | SDNN (95% CI) | RMSSD (95% CI) | pNN50 (95% CI) | nVLF (95% CI) | nLF (95% CI) | nHF (95% CI) | |||||||
| ECG | |||||||||||||
|
|
0-1 | 0.01 (–0.35 to 0.36) | –0.07 (–0.43 to 0.29) | –0.10 (–0.46 to 0.26) | –0.03 (–0.39 to 0.33) | 0.40 (0.04 to 0.76) | –0.38 (–0.74 to –0.02) | ||||||
|
|
1-2 | –0.12 (–0.48 to 0.24) | –0.04 (–0.39 to 0.32) | –0.09 (–0.44 to 0.27) | 0.05 (–0.31 to 0.41) | 0.08 (–0.28 to 0.44) | –0.09 (–0.45 to 0.27) | ||||||
|
|
2-3 | 0.05 (–0.31 to 0.41) | 0.05 (–0.31 to 0.41) | 0.01 (–0.34 to 0.37) | –0.01 (–0.61 to 0.11) | 0.34 (–0.02 to 0.71) | –0.26 (–0.62 to 0.10) | ||||||
|
|
3-4 | 0.05 (–0.31 to 0.40) | 0.05 (–0.31 to 0.41) | 0.04 (–0.32 to 0.40) | –0.04 (–0.40 to 0.32) | 0.29 (–0.07 to 0.65) | –0.27 (–0.63 to 0.08) | ||||||
|
|
4-5 | 0.12 (–0.23 to 0.48) | 0.08 (–0.28 to 0.44) | 0.11 (–0.24 to 0.47) | –0.20 (–0.56 to 0.16) | 0.25 (–0.11 to 0.61) | –0.20 (–0.56 to 0.16) | ||||||
|
|
0-2 | –0.07 (–0.43 to 0.29) | 0.06 (–0.41 to 0.30) | –0.09 (–0.45 to 0.26) | –0.02 (–0.37 to 0.34) | 0.35 (0.00 to 0.72) | –0.34 (–0.70 to 0.02) | ||||||
|
|
0-3 | 0.04 (–0.40 to 0.32) | –0.03 (–0.38 to 0.33) | –0.06 (–0.41 to 0.30) | 0.14 (–0.22 to 0.49) | 0.08 (–0.28 to 0.44) | –0.11 (–0.46 to 0.25) | ||||||
|
|
0-4 | 0.03 (–0.38 to 0.33) | –0.01 (–0.37 to 0.34) | –0.03 (–0.39 to 0.33) | 0.06 (–0.30 to 0.42) | 0.01 (–0.35 to 0.37) | –0.02 (–0.38 to 0.34) | ||||||
| PEP | |||||||||||||
|
|
0-1 | 0.01 (–0.35 to 0.37) | –0.07 (–0.43 to 0.29) | –0.10 (–0.46 to 0.26) | 0.01 (–0.35 to 0.36) | 0.38 (0.02 to 0.74) | –0.37 (–0.73 to –0.01) | ||||||
|
|
1-2 | –0.12 (–0.48 to 0.24) | –0.03 (–0.39 to 0.32) | –0.08 (–0.44 to 0.27) | 0.05 (–0.31 to 0.41) | 0.09 (–0.26 to 0.45) | –0.10 (–0.46 to 0.26) | ||||||
|
|
2-3 | 0.05 (–0.31 to 0.41) | 0.06 (–0.30 to 0.42) | 0.03 (–0.33 to 0.39) | –0.25 (–0.61 to 0.10) | 0.33 (–0.03 to 0.69) | –0.24 (–0.60 to 0.11) | ||||||
|
|
3-4 | 0.04 (–0.31 to 0.40) | 0.04 (–0.31 to 0.40) | 0.04 (–0.32 to 0.40) | –0.07 (–0.43 to 0.29) | 0.25 (–0.11 to 0.61) | –0.23 (–0.59 to 0.13) | ||||||
|
|
4-5 | 0.12 (–0.24 to 0.48) | 0.08 (–0.28 to 0.44) | 0.10 (–0.26 to 0.46) | –0.23 (–0.59 to 0.13) | 0.30 (–0.06 to 0.66) | –0.23 (–0.59 to 0.13) | ||||||
|
|
0-2 | –0.06 (–0.42 to 0.29) | –0.06 (–0.41 to 0.30) | –0.09 (–0.45 to 0.27) | –0.03 (–0.39 to 0.33) | 0.38 (0.03 to 0.75) | –0.36 (–0.73 to 0.00) | ||||||
|
|
0-3 | –0.03 (–0.39 to 0.33) | –0.02 (–0.38 to 0.33) | –0.05 (–0.41 to 0.31) | 0.13 (–0.23 to 0.49) | 0.10 (–0.26 to 0.45) | –0.12 (–0.48 to 0.24) | ||||||
|
|
0-4 | –0.02 (–0.38 to 0.34) | –0.01 (–0.37 to 0.34) | –0.03 (–0.38 to 0.33) | 0.06 (–0.30 to 0.42) | 0.02 (–0.34 to 0.37) | –0.03 (–0.39 to 0.33) | ||||||
aECG: electrocardiogram; nHF: normalized high-frequency power; nLF: normalized low-frequency power; nVLF: normalized very-low–frequency power; PEP: Pulse Express PRO; pNN50: proportion of NN50 divided by the total number of RR intervals; RMSSD: root mean square of successive R-R intervals; SDNN: standard deviation of normal R-R intervals.