Table 3. Comparison of cardiac autonomic function test (supine) parameters between NFG and IFG group.
| Parameters/Group | NFG (n = 76) | IFG (n = 47) | p value |
| Short-term HRV at rest: Frequency domain parameters | |||
| ln(LF) | 2.14±0.4 | 2.07±0.4 | 0.317 |
| ln(HF) | 2.2±0.45 | 1.95±0.41 | 0.002 |
| ln(TP) | 2.62±0.34 | 2.46±0.33 | 0.011 |
| LF/HF ratio | 1.18±1.07 | 1.98±1.92 | 0.018 |
| LF nu | 47.18±16.47 | 55.75±19.51 | 0.014 |
| HF nu | 52.82±16.47 | 44.25±19.51 | 0.014 |
| Short-term HRV at rest: Time domain parameters | |||
| SDNN (ms) | 37.82±15.61 | 30.94±11.92 | 0.023 |
| RMSSD (ms) | 37.59±20.53 | 27.63±12.95 | 0.007 |
| NN50 (count) | 55.04±56.9 | 33.96±42.72 | 0.023 |
| pNN50 | 16.93±18.37 | 10.11±12.78 | 0.021 |
| Cardiac autonomic reactivity tests | |||
| HRFTB (bpm) | 25.35±9.6 | 21.74±6.87 | 0.076 |
| 30/15 ratio | 1.58±0.23 | 1.49±0.23 | 0.036 |
| HRVAL (bpm) | 48.13±16.99 | 47.42±16.33 | 0.819 |
| VCR (mm Hg) | 31.95±10.49 | 31.6±9.94 | 0.852 |
Data are expressed as Mean ± standard deviation; LF, low frequency spectral power; HF, high frequency spectral power; TP, total spectral power; nu, normalized units; HRV, heart rate variability; RR, R to R wave; SD, standard deviation; RMSSD–root mean square of successive standard deviation of RR interval; NN50, consecutive R to R interval differs more than 50 ms; p, percentage; HRFTB, HR difference during forced timed breathing; 30/15 ratio, ratio of longest to shortest RR interval in response to orthostatic stress; HRVAL, heart rate difference during and after Valsalva maneuver; VCR, vasoconstrictor reserve. p-value<0.05 considered statistically significant.