Table 1.
HRV and Plasma NE Concentrations
| Control | SS | VNS | p Value | |
|---|---|---|---|---|
| HRV | ||||
| n | 4 | 5 | 4 | |
| Heart rate, beats/min | 337 ± 5 | 367 ± 20 | 351 ± 12 | 0.381 |
| HF, ms2 | 2.0 ± 0.3 | 0.3 ± 0.1∗ | 1.1 ± 0.2† | <0.001 |
| LF, ms2 | 8.0 ± 1.8 | 1.4 ± 0.4∗ | 2.8 ± 0.3 | 0.002 |
| LF/HF ratio | 4.3 ± 1.4 | 6.8 ± 1.5 | 2.8 ± 0.6 | 0.127 |
| SDNN, ms | 8.6 ± 2.1 | 4.3 ± 0.8 | 5.0 ± 0.5 | 0.077 |
| Sympathetic activation | ||||
| n | 9 | 9 | 10 | |
| Plasma NE concentration, pg/ml | 378 ± 58 | 7800 ± 2992‡ | 978 ± 306† | 0.019 |
Values are mean ± SEM. Differences were tested by using 1-way analysis of variance, followed by post hoc Tukey-Kramer test.
HF = high-frequency component of heart rate variability (HRV) (0.04 to 0.73 Hz); LF = low-frequency component of HRV (0.73–2.0 Hz); NE = norepinephrine; SDNN = SD of the normal to normal intervals; VNS = vagal nerve stimulation.
‡
p < 0.05 and *p < 0.01 vs. control.
†
p < 0.05 vs. sham stimulation (SS).