Table 2.

Cardiovascular responses to treatment in neuropathic and hyperadrenergic POTS

		Placebo		Midodrine
Parameter	Tilt angle...	0°	35°	0°	35°	P value
HR (beats/min)
Neuropathic POTS		69 ± 4	93 ± 6	63 ± 3‡	79 ± 3‡	0.0002
Hyperadrenergic POTS		70 ± 4	91 ± 6	69 ± 7	87 ± 4	0.3
MAP (mmHg)
Neuropathic POTS		77 ± 3	77 ± 2	79 ± 2†	84 ± 3†	0.006
Hyperadrenergic POTS		81 ± 2	82 ± 2	77 ± 3	77 ± 5	0.6
Q̇calf (ml/100 ml per min)
Neuropathic POTS		2.31 ± 0.4	3.56 ± 0.9	1.89 ± 0.2†	1.09 ± 0.2†	0.008
Hyperadrenergic POTS		1.90 ± 0.3	1.62 ± 0.2	1.82 ± 0.2	1.28 ± 0.2	0.08
CVR [mmHg/(ml/100 ml per min)]
Neuropathic POTS		27 ± 3	57 ± 12	33 ± 4‡	93 ± 15‡	0.001
Hyperadrenergic POTS		34 ± 4	52 ± 13	35 ± 6	59 ± 14	0.9
Cv (ml/100ml)
Neuropathic		4.00 ± 0.4		2.26 ± 0.4†		0.002
Hyperadrenergic		3.95 ± 0.6		3.20 ± 0.6*		0.02

Values are means ± S.E.M.

^*P < 0.05

^†P < 0.01

^‡P < 0.001 compared with the cross-over treatment within group.