Table 2.
Cardiac autonomic indices: summary statistics and non-parametric 2-tailed Mann-Whitney and Kolmogorov-Smirnov exact significance tests
| Variable | No MetS | MetS | All | MW test P | KS test P |
|---|---|---|---|---|---|
| HR (bpm) | 68.12 ± 6.67 | 70.13 ± 8.28 | 68.67 ± 7.10 | 0.183 | 0.166 |
| RR mean (ms) | 880.80 ± 78.53 | 855.50 ± 109.94 | 873.70 ± 82.62 | 0.182 | 0.167 |
| RR TP (ms2) | 1,071.53 ± 553.56 | 603.78 ± 289.06 | 751.76 ± 410.29 | < 0.001* | < 0.001* |
| RR LFa (ms2) | 222.22 ± 142.35 | 148.58 ± 106.00 | 163.09 ± 114.79 | 0.182 | 0.358 |
| RR HFa (ms2) | 163.39 ± 135.66 | 108.66 ± 71.94 | 142.22 ± 108.19 | 0.016* | 0.028* |
| RR LFnu (nu) | 43.73 ± 15.24 | 50.30 ± 14.90 | 49.10 ± 15.57 | 0.310 | 0.211 |
| RR HFnu (nu) | 45.11 ± 14.26 | 38.72 ± 14.96 | 41.59 ± 15.28 | 0.193 | 0.396 |
| RR LF/HF | 0.95 ± 0.59 | 1.30 ± 0.72 | 1.14 ± 0.66 | 0.217 | 0.357 |
| ΔRR LFnu (nu) | 23.70 ± 19.08 | 17.21 ± 15.73 | 21.22 ± 16.21 | 0.128 | 0.263 |
| Alpha index (ms/mmHg) | 13.85 ± 4.71 | 6.92 ± 2.88 | 10.39 ± 4.65 | < 0.001* | < 0.001* |
| SAP mean (mmHg) | 117.61 ± 7.49 | 130.14 ± 13.46 | 122.10 ± 10.96 | < 0.001* | < 0.001* |
| SAP TP (mmHg2) | 13.27 ± 6.40 | 16.44 ± 9.54 | 13.34 ± 7.09 | 0.093 | 0.228 |
| SAP LFa (mmHg2) | 1.94 ± 0.89 | 3.30 ± 2.56 | 2.50 ± 1.47 | 0.032* | 0.011* |
Values are presented as median±median absolute deviation. The MW and KS tests were applied as described below Table 1.
*Significant P-value.
MetS, metabolic syndrome; MW, Mann-Whitney; KS, Kolmogorov-Smirnov; HR, heart rate; RR, RR interval; TP, total power; LF, low frequency; a, absolute value; HF, high frequency; nu, normalized unit; ΔRR LFnu, change induced by standing up on the LF component of RR variability expressed in nu; SAP, systolic arterial pressure.