Table 2.
Baseline measures of cardiac and peripheral autonomic control evaluated by linear and nonlinear approaches.
| Rest_tVNS off (n = 13) | Rest_tVNS on (n = 13) | P | |
|---|---|---|---|
| Linear Analysis | |||
| R–R interval | |||
| HR (beats/min) | 66 (61–68) | 63 (60–66) | <0.01 |
| Variance (ms2) | 2572 (1494–4291) | 2549 (1717–3331) | 0.54 |
| VLF abs. (ms2) | 1146 (580–1475) | 1132 (485–1439) | 0.98 |
| LF n.u. (%) | 41 (19–62) | 53 (28–63) | 0.27 |
| HF n.u. (%) | 57 (35–71) | 46 (35–69) | 0.45 |
| LF/HF | 0.7 (0.3–1.9) | 1.2 (0.4–1.8) | 0.50 |
| Systolic Arterial Pressure | |||
| Variance (mmHg2) | 19 (8–27) | 13 (6–19) | <0.01 |
| LF abs. (mmHg2) | 1.0 (0.6–2.2) | 1.4 (0.6–2.8) | 0.37 |
| Respiratory Rate | |||
| HF (Hz) | 0.29 (0.20–0.33) | 0.29 (0.26–0.31) | 0.73 |
| Nonlinear Analysis | |||
| R–R interval patterns | |||
| 0V (%) | 18 (8–27) | 17 (5–20) | <0.01 |
| 1V (%) | 45 (44–52) | 49 (43–52) | 0.24 |
| 2LV (%) | 11 (7–22) | 12 (10–20) | 0.95 |
| 2UV (%) | 21 (11–32) | 25 (16–33) | 0.31 |
| Systolic Arterial Pressure Pattern | |||
| 0V (%) | 36 (14–47) | 17 (13–30) | <0.01 |
Median (25th–75th). tVNS = transcutaneous vagus nerve stimulation; HR = heart rate; VLF = very low frequency; LF = low frequency; HF = high frequency; LF/HF = sympathovagal balance; n.u. = normalized unit, ω = central frequency.