Table 1.

Baseline demographics, and postural vital signs and catecholamines of the subjects with Postural Tachycardia Syndrome in the 2 protocols.

	Protocol #1		Protocol #2
	(n=54)		(n=18)
Female (n)	49 (91%)		16 (89%)
Age (years)	34 ± 10		33 ± 8
Supine
Heart Rate (min−1)	76 ± 13		78 ± 13
Systolic Blood Pressure (mmHg)	110 ± 12		111 ± 16
Diastolic Blood Pressure (mmHg)	68 ±8		70 ± 10
Norepinephrine (nmol/l)	1.65 ± 1.41		1.86 ± 2.13
Epinephrine (nmol/l)	0.15 ± 0.14		0.19 ± 0.19
Standing
Heart Rate (min−1)	122 ± 26	**	130 ± 29	**
Systolic Blood Pressure (mmHg)	115 ± 22		118 ± 24
Diastolic Blood Pressure (mmHg)	74 ± 14	*	79 ± 16	*
Norepinephrine (nmol/l)	4.94 ± 3.35	**	3.93 ± 2.21	*
Epinephrine (nmol/l)	0.45 ±0.75	*	0.50 ± 1.05
Change from Supine to Standing
Heart Rate (min−1)	46 ± 24		52 ± 27
Systolic Blood Pressure (mmHg)	5 ± 19		7 ± 24
Diastolic Blood Pressure (mmHg)	6 ± 13		9 ± 15
Norepinephrine (nmol/l)	3.22 ± 3.22		1.80 ± 2.64
Epinephrine (nmol/l)	0.31 ± 0.68		0.31 ± 0.93

Data are presented as the mean ± standard deviation. Reported P values are for paired t-tests comparing supine and upright parameters.

^*P<0.05;

^**P<0.001