Table 2.
HRV Values According to COPD Severity by Spirometric Stage.
| Grade 0 (n = 4) |
Grade 1 (n = 16) |
Grade 2 (n = 30) |
Grade 3 (n = 23) |
Grade 4 (n = 6) |
p Value | |
|---|---|---|---|---|---|---|
| HR (min) | 68.3 ± 1.9 | 71.2 ± 3.3 | 71.8 ± 3.3 | 71.7 ± 3.8 | 71.4 ± 1.2 | 0.305 |
| SDNN (ms) | 58.6 ± 10.4 | 62.3 ± 5.1 | 56.1 ± 9.1 | 58.1 ± 8.3 | 61.6 ± 2.9 | 0.184 |
| HF (normalized units) | 41.1 ± 0.3 | 42.7 ± 4.8 | 39.9 ± 5.6 | 39.5 ± 5.3 | 38.8 ± 5.4 | 0.121 |
| LF/HF | 2.3 ± 0.1 | 2.5 ± 0.3 | 2.5 ± 0.6 | 2.2 ± 0.5 | 2.3 ± 0.4 | 0.205 |
Values are presented as mean ± standard deviation. HRV = heart rate variability; COPD = chronic obstructive pulmonary disease; HR = heart rate; SDNN = standard deviation of N-N interval; HF = high frequency; LF = low frequency.