Table 2.
HRV indices before and after active postural change from supine position to orthostatic position
| COPD (n = 12)
|
COPD+OSAS (n = 12)
|
Group | Position | Interaction | |||
|---|---|---|---|---|---|---|---|
| Supine | Orthostasis | Supine | Orthostasis | ||||
| Time | – | – | – | – | |||
| iRR | 794 ± 103 | 719 ± 114* | 818 ± 123 | 764 ± 97* | 0.27 | 0.04 | 0.74 |
| SDNN | 13.9 ± 5.3 | 11.7 ± 6.6 | 16.1 ± 5.8 | 15.2 ± 7.3 | 0.12 | 0.38 | 0.73 |
| RMSSD | 14.3 ± 7.2 | 11.5 ± 6.5 | 15.8 ± 7.9 | 13.7 ± 6.9 | 0.42 | 0.21 | 0.78 |
| pnn50 | 1.7 ± 2.8 | 0.6 ± 1.1 | 1.8 ± 3.7 | 0.5 ± 0.9 | 0.98 | 0.11 | 0.85 |
| TINN | 67.0 ± 22.2 | 55.4 ± 30.4 | 77.9 ± 28.3 | 77.0 ± 34.6 | 0.06 | 0.46 | 0.52 |
| Frequency | – | – | – | – | |||
| LF_abs | 79.8 ± 84.8 | 69.2 ± 66.6 | 156.7 ± 107.7+ | 161.3 ± 144.2+ | ,0.01 | 0.92 | 0.80 |
| HF_abs | 67.5 ± 47.8 | 60.9 ± 101.2 | 106.7 ± 115.1 | 70.6 ± 61.3 | 0.39 | 0.33 | 0.55 |
| LF_nu | 50.1 ± 19.9 | 58.3 ± 19.5 | 62.9 ± 14.8+ | 68.6 ± 14.7+ | 0.02 | 0.17 | 0.80 |
| HF_nu | 49.7 ± 19.8 | 41.2 ± 19.4 | 36.7 ± 14.8 | 31.0 ± 14.6 | 0.02 | 0.16 | 0.78 |
| LF/HF | 1.3 ± 1.0 | 3.0 ± 4.7 | 2.1 ± 1.2 | 4.6 ± 7.4 | 0.37 | 0.11 | 0.75 |
| Non-linear | – | – | – | – | |||
| SD1 | 10.4 ± 5.1 | 8.1 ± 4.6 | 11.2 ± 5.6 | 9.7 ± 4.9 | 0.43 | 0.21 | 0.78 |
| SD2 | 16.3 ± 6.6 | 14.3 ± 8.4 | 19.7 ± 6.7 | 18.9 ± 9.5 | 0.08 | 0.53 | 0.78 |
Notes:
Significant difference between supine position and orthostatic position.
Significant difference between the COPD group and the COPD+OSAS group. The variables are presented as mean ± SD.
Abbreviations: HRV, heart rate variability; COPD, chronic obstructive pulmonary disease; OSAS, obstructive sleep apnea syndrome; iRR, interval between consecutive heart beats; SDNN, standard deviation of all R-R intervals; RMSSD, square root of the mean squared differences between adjacent R-R intervals; pnn50, percentage of adjacent R-R intervals with duration difference greater than 50 ms; TINN, triangular interpolation of the iRR interval histogram; LF_abs, absolute power in the low frequency band; HF_abs, absolute power in the high frequency band; LF_nu, normalized power in the low frequency band; HF_nu, normalized power in the high frequency band; LF/HF, low frequency to high frequency ratio; SD1, standard deviation of instantaneous beat-to-beat variability; SD2, long-term standard deviation of the continuous R-R interval.