Table 2.

Hemodynamic responses during graded upright tilt

Variables	POTS Patients (n = 27)					Healthy Controls (n = 16)
	Supine	30° Tilt	60° Tilt			Supine	30° Tilt	60° Tilt
			5 min	20 min	40 min			5 min	20 min	40 min
SBP (mmHg)	105 [98, 114]	112* [105, 120]	113* [109, 124]	112* [105, 118]	114* [106, 120]	109 [106, 115]	116 [105, 123]	116 [109, 122]	114 [107, 116]	112 [109, 115]
DBP (mmHg)	66 [60, 69]	70** [63, 74]	77** [67, 81]	76** [68, 83]	72** [67, 81]	63 [59, 69]	69** [66, 75]	72** [70, 82]	73** [70, 77]	75** [71, 77]
HR (bpm)	77†† [70, 90]	84**†† [75, 94]	104**†† [96, 111]	107**†† [102, 122]	110**†† [103, 125]	68 [61, 76]	70** [65, 82]	83** [77, 93]	87** [82, 99]	87** [83, 108]
CO (l/min)	5.0†† [4.3, 5.4]	4.4**†† [4.0, 5.0]	3.6**†† [3.3, 4.4]	3.5**†† [3.1, 3.8]	3.2**†† [2.9, 3.8]	6.8 [5.9, 7.3]	5.9** [5.0, 6.9]	5.1** [4.5, 6.1]	4.4** [4.0, 5.2]	4.2** [3.9, 4.7]
SV (ml)	59†† [50, 66]	47**†† [38, 56]	36**†† [28, 42]	30**†† [25, 37]	29**†† [23, 35]	86 [74, 100]	76** [60, 102]	60** [45, 76]	47** [39, 64]	42** [36, 56]
TPR (dyn·s·cm−5)	1284†† [1106, 1501]	1566**†† [1328, 1735]	1867**†† [1573, 2314]	1959**†† [1788, 2336]	2137**†† [1805, 2493]	944 [859, 1057]	1063** [957, 1504]	1309** [1130, 1623]	1475** [1346, 1799]	1635** [1362, 1790]

Values are expressed as median [25%, 75%]. SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; CO, cardiac output; SV, stroke volume; TPR, total peripheral resistance.

^**P < 0.01 vs supine baseline within the same group;

^††P<0.01 vs healthy controls.