Table 2.
Autonomic Function Tests
| Parameter | MSA | PAF | Healthy controls | P value |
|---|---|---|---|---|
| Supine SBP, mm Hg | 15153 (137 to 168) | 151 (139 to 170) | 118 (107 to 133) | 0.001** |
| Supine DBP, mm Hg | 88 (79 to 95) | 85 (73 to 91) | 83 (74 to 83) | 0.083 |
| Supine HR, bpm | 70 (66 to 77) | 71 (61 to 77) | 66 (62 to 76) | 0.640 |
| Upright SBP, mmHg | 82 (74 to 99) | 81 (71 to 101) | 110 (103 to 138) | 0.003** |
| Upright DBP, mmHg | 54 (45 to 62) | 52 (43 to 60) | 79 (74 to 87) | 0.001** |
| Upright HR, bpm | 86 (68 to 91) | 79 (74 to 91) | 82 (70 to 84) | 0.703 |
| S/A ratio (normal >1.2) | 1.1 (1.0 to 1.1) | 1.0 (1.0 to 1.1) | 1.3 (1.2 to 1.5) | <0.001** |
| Valsalva phase II, mmHg | −72 (−87 to −55) | −61 (−78 to −45) | −16 (−24 to −1) | <0.001** |
| Valsalva phase IV, mmHg | −36 (−42 to −28) | −42 (−48 to −32) | 15 (14 to 22) | <0.001** |
| Valsalva ratio | 1.1 (1.1 to 1.2) | 1.1 (1.0 to 1.1) | 1.5 (1.4 to 1.7) | <0.001** |
| Hyperventilation, mmHg | −16 (−28 to −10) | −31 (−52 to −13) | 0.5 (−5 to 5) | <0.001** |
| Cold- Pressor, mmHg | 1 (−2 to 12) | 8 (−3 to 16) | 17 (8 to 24) | 0.030* |
| Handgrip, mmHg | 3 (−3 to 8) | 7 (−6 to 15) | 17 (8 to 26) | 0.017* |
Values represent median (interquartile range, IQR). MSA, multiple system atrophy; PAF, pure autonomic failure; SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; ∆SBP, orthostatic change in SBP; ∆DBP, orthostatic change in DBP; and ∆HR, orthostatic change in HR. S/A represents sinus arrhythmia ratio calculated by the maximum divided by the minimum heart rate values during controlled breathing.
*
P<0.05,
**
P<0.01