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Table 3 Cardiovascular variables: baseline, response to 20° HUT and response to imagery upright position

From: Orthostatic responses in adolescent chronic fatigue syndrome: contributions from expectancies as well as gravity

 

Baseline

Delta tilt (response to 20° HUT)

Delta imagination (response to imagery upright position)

 

CFS patients

Healthy controls

p-value

CFS patients

Healthy controls

p-value

CFS patients

Healthy controls

p-value

Heart rate – beats/min, mean (SD)

81 (13)

71 (9.9)

0.001

4.5 (4.2)

3.2 (3.4)

0.192

1.8 (2.2)

1.4 (2.3)

0.470

Systolic blood pressure – mm Hg, mean (SD)

111 (10)

109 (9.8)

0.260

-0.18 (2.9)

0.17 (4.6)

0.701

0.37 (2.6)

0.24 (1.9)

0.819

Diastolic blood pressure – mm Hg, mean (SD)

69 (7.6)

64 (7.2)

0.017

1.5 (2.4)

1.8 (4.2)

0.783

0.25 (1.6)

0.31 (1.8)

0.886

Mean arterial blood pressure – mm Hg, mean (SD)

84 (8.1)

79 (7.4)

0.025

0.85 (2.6)

1.4 (3.9)

0.466

0.26 (1.8)

0.42 (2.0)

0.727

Stroke index – ml/m2, mean (SD)

47 (8.8)

51 (5.9)

0.049

-4.8 (4.1)

-4.5 (3.7)

0.690

-0.59 (1.6)

-0.07 (1.3)

0.162

Cardiac index – l/min/m2, mean (SD)

3.8 (0.59)

3.6 (0.48)

0.208

-0.17 (0.24)

-0.14 (0.23)

0.675

0.03 (0.13)

0.06 (0.10)

0.340

Total peripheral resistance index – mm Hg/l/min/m2, mean (SD)

7.9 (1.6)

8.6 (1.9)

0.099

0.55 (0.78)

0.67 (1.0)

0.587

-0.06 (0.37)

-0.14 (0.39)

0.397

LFnorm – nu, mean (SD)

51 (19)

51 (15)

0.953

8.3 (9.8)

6.7 (12)

0.560

0.64 (4.7)

-1.4 (3.3)

0.042

HFnorm – nu, mean (SD)

49 (19)

49 (15)

0.953

-8.2 (9.7)

-6.8 (12)

0.579

-0.64 (4.7)

1.4 (3.3)

0.042

LFabs – ms2, median (IQR)

457 (411)

884 (770)

0.001

-36 (409)

-92 (675)

0.753

1.9 (66)

-34 (99)

0.026

HFabs – ms2, median (IQR)

440 (659)

766 (967)

0.012

-266 (888)

-370 (1019)

0.952

-0.9 (64)

-18 (91)

0.628

LF/HF – median (IQR)

0.97 (1.8)

1.1 (0.93)

0.942

0.16 (0.60)

0.20 (0.55)

0.818

0.004 (0.19)

-0.07 (0.14)

0.025

Total power - ms2, median (IQR)

1092 (1415)

2172 (2260)

0.001

-296 (1014)

-320 (2278)

0.952

-28 (131)

-64 (207)

0.107

  1. P-values are based on Student t-test or Mann-Whitney's test, as appropriate. SD = standard deviation, IQR = interquartile range. LFnorm = Heart rate variability in the low-frequency range, normalized units; HFnorm = Heart rate variability in the high-frequency range, normalized units; LFabs = Heart rate variability in the low-frequency range, absolute units; HFabs = Heart rate variability in the high-frequency range, absolute units. Bold numbers indicate p ≤ 0.05.