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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.
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