Table 1.
Hemodynamic parameters, respiratory activity and sympathetic post-ganglionic discharge activity (MSNA) while supine (REST), during the asymptomatic phase of tilt (T1) and the period of tilt just preceding syncope (T2). Values are expressed as mean ± standard deviation.
| Parameters | REST | T1 | T2 |
|---|---|---|---|
| RR (msec) | 847 ± 99 | 609 ± 84 * | 444 ± 87 § |
| SAP (mmHg) | 131 ± 12 | 133 ± 10 | 114 ± 14 #§ |
| DAP (mmHg) | 76 ± 7 | 88 ± 8 * | 71 ± 9 # |
| Resp (breaths/min) | 17 ± 6 | 16 ± 3 | 18 ± 4 |
| MSNA (bursts/min) | 17 ± 6 | 30 ± 5 * | 34 ± 9 § |
| MSNA (bursts/100 beats) | 25 ± 8 | 31 ± 6 | 25 ± 5 |
* p < 0.05 REST vs T1. # p < 0.05 T1 vs T2. § p < 0.05 REST vs T2. RR: RR interval; SAP: systolic arterial pressure; DAP: diastolic arterial pressure; Resp: respiratory activity; MSNA: muscle sympathetic nerve activity.