Comparison of BPV parameters, HRV indices, and CAFT parameters between healthy control and pre-MetS subjects
| Variable | Total subjects (n = 182) |
Control subjects (n = 89) |
Pre-MetS subjects (n = 93) |
p-value |
|---|---|---|---|---|
| BPV parameters | ||||
| BHR (per min) | 72.0 (66.96–79.33) | 70.78 (66.08–78.08) | 73.0 (67.35–81.50) | 0.032 |
| SBP (mmHg) | 118.44 ± 10.36 | 115.40 ± 9.64 | 121.36 ± 10.24 | 0.001 |
| DBP (mmHg) | 74.29 ± 9.29 | 71.98 ± 8.32 | 76.49 ± 9.66 | 0.001 |
| MAP (mmHg) | 90.39 ± 10.01 | 86.38 ± 7.82 | 94.22 ± 10.40 | 0.001 |
| RPP (mmHg/min) | 85.05 (75.32–99.52) | 80.0 (72.50–89.75) | 91.40 (79.25–108.85) | 0.001 |
| BRS (ms/mmHg) | 15.70 ± 6.93 | 17.43 ± 7.17 | 14.03 ± 6.29 | 0.001 |
| Time-domain indices of HRV | ||||
| Mean RR (ms) | 848.29 ± 116.08 | 869.43 ± 112.18 | 828.05 ± 116.74 | 0.016 |
| SDNN (ms) | 40.70 (28.47–56.27) | 43.7 (31.80–59.40) | 38.90 (26.05–48.25) | 0.011 |
| RMSSD (ms) | 45.50 (33.75–56.0) | 52.0 (38.15–59.70) | 40.70 (23.55–49.20) | 0.001 |
| NN50 | 30.70 (6.0–66.0) | 42.0 (16.0–67.0) | 17 (2.5–64.5) | 0.001 |
| pNN50 (%) | 8.40 (1.68–18.05) | 12.20 (4.15–18.65) | 4.9 (0.80–17.45) | 0.001 |
| Frequency-domain indices of HRV | ||||
| TP (ms2) | 1,302.50 (707.25–1868.25) | 1,384.0 (965.0–2108.50) | 1,090.0 (581.5–1689.5) | 0.003 |
| HF (ms2) | 434.50 (186.5–676.50) | 463.0 (243.0–688.50) | 407.0 (120.0–683.0) | 0.046 |
| LF (ms2) | 404.0 (193.0–663.0) | 476.0 (231.0–664.50) | 315.0 (157.5–652.10) | 0.034 |
| VLF (ms2) | 354.0 (67.0–651.0) | 403.0 (116.0–667.0) | 169.0 (48.5–543.0) | 0.007 |
| HF (nu) | 50.02 (36.58–56.93) | 52.74 (37.43–64.02) | 47.80 (36.56–55.67) | 0.020 |
| LF (nu) | 53.52 (43.56–59.28) | 47.19 (35.93–62.49) | 55.27 (47.1–69.8) | 0.001 |
| LF/HF | 1.20 (0.67–2.11) | 0.88 (0.56–1.67) | 1.44 (0.71–2.57) | 0.001 |
| Cardiac autonomic function test parameters | ||||
| E:I ratio | 1.36 (1.21–1.48) | 1.41 (1.31–1.52) | 1.28 (1.15–1.43) | 0.001 |
| 30:15 ratio | 1.30 (1.21–1.50) | 1.40 (1.24–1.56) | 1.26 (1.15–1.43) | 0.001 |
| ΔDBPIHG | 16.0(12.75–23.0) | 14 (12.0–21.0) | 17 (14.0–26.0) | 0.002 |
The values are expressed as median (inter-quartile range) or mean ± SD. BPV, blood pressure variability; HRV, heart rate variability; CAFT, cardiac autonomic function test; MetS, metabolic syndrome; BHR, basal heart rate; SBP, systolic blood pressure; DBP, diastolic blood pressure; MAP, mean arterial pressure; RPP, rate pressure product; BRS, baroreflex sensitivity; Mean RR, mean-RR interval; SDNN, standard deviation of normal to normal interval; RMSSD, square root of the mean squared differences of successive normal to normal intervals; NN50, the number of interval differences of successive NN intervals greater than 50 ms; PNN50, the proportion derived by dividing NN50 by the total number of NN intervals; TP, total power; HF, high-frequency power; HF nu, HF power in normalized units (HF / (TP–VLF) × 100); LF, low-frequency power; LF nu, LF power in normalized units (LF / (TP–VLF) × 100); VLF, very-low-frequency; LF/HF, a ratio of the low-frequency component to the high-frequency; E:I ratio, a ratio of maximum RR interval during expiration to minimum RR interval during inspiration following deep breathing; ΔDBPIHG, a maximum rise in diastolic BP above baseline following sustained handgrip.