Table 1.
Supine Hemodynamic and Neurocardiopulmonary Data
| Variable | Control Group (n=16) | POTS‐↓CO Group (n=12) | POTS–Normal CO Group (n=32) | POTS‐Hyperventilation Group (n=14) |
|---|---|---|---|---|
| Heart rate, bpm | 64±3 | 83±5a | 74±5 | 74±5 |
| Systolic BP, mm Hg | 115±3 | 103±2a | 114±3 | 118±5 |
| Diastolic BP, mm Hg | 60±2 | 63±4 | 68±2a | 62±2 |
| MAP, mm Hg | 79±4 | 77±4 | 81±4 | 81±3 |
| Pulse pressure, mm Hg | 54±3 | 42±4a | 47±3 | 56±4 |
| Respiratory rate, breaths/min | 14±1 | 15±1 | 14±1 | 15±1 |
| VE, L/min | 6.8±0.7 | 7.4±0.7 | 6.7±0.7 | 7.9±0.9 |
| Tidal volume, L | 0.49±0.03 | 0.50±0.08 | 0.51±0.05 | 0.54±0.04 |
| ETCO2, Torr | 41.4±0.6 | 40.2±0.8 | 41.9±0.5 | 39.4±1.2 |
| Cardiac output, L/min | 5.7±0.4 | 3.4±0.2a | 5.8±0.4 | 5.6±0.7 |
| SVR, mm Hg/L per min | 16.3±1.5 | 21.6±1.5a | 15.1±1.0 | 15.6±1.4 |
| Mean CBFv, cm/s | 72±3 | 73±6 | 75±3 | 79±4 |
Data are given as mean±SEM. The 3 groups were as follows: (1) POTS‐↓CO, decreased CO without hyperventilation, defined by CO <4 L/min; (2) POTS–normal CO, normal CO without hyperventilation, defined by CO >4 L/min; and (3) POTS‐hyperventilation, hyperventilation. BP indicates blood pressure; bpm, beats per minute; CBFv, cerebral blood flow velocity; CO, cardiac output; ETCO2, end tidal CO2; MAP, mean arterial pressure; POTS, postural tachycardia syndrome; SVR, systemic vascular resistance; VE, minute ventilation.
a
Different from control, P<0.05.