. 2011 Oct 24;122(Pt 4):183–192. doi: 10.1042/CS20110200

Table 3. Autonomic and neurohormonal profile in CFS–POTS and non-CFS–POTS.

Values are means±S.E.M. DBP, diastolic BP; SBP, systolic BP; LF, low frequency; HF, high frequency; RRI, R–R heart rate interval. Control values from the Autonomic Dysfunction Center Database at Vanderbilt University are presented as a reference.

	Non-CFS POTS		CFS-POTS			Controls
Test	Value	n	Value	n	P value	Value	n
Orthostatic stress test
Supine
SBP (mmHg)	104±3	17	108±2	30	0.385	100±2	22
DBP (mmHg)	67±2	17	67±2	30	0.963	65±2	22
HR (beats/min)	75±3	17	73±1	30	0.495	62±2	22
10 min standing
SBP (mmHg)	109±4	15	113±4	28	0.509	100±3	22
DBP (mmHg)	72±2	15	73±2	28	0.755	69±2	22
HR (beats/min)	115±6	15	122±3	28	0.244	85±2	22
Total standing time (min)	21±2	17	20±2	30	0.902	27±2	22
ΔHR at maximal tolerance (beats/min)^*	40±4	17	51±3	30	0.030	26±3	22
Valsalva manoeuvre^†
Early phase II ΔSBP (mmHg)	−24±4	17	−24±3	27	0.838	−14±3	21
Late phase II ΔSBP (mmHg)^‡	11±2	17	18±3	27	0.041	10±2	21
Phase II ΔHR (beats/min)	37±4	17	42±3	27	0.642	25±3	21
Phase IV overshoot ΔSBP (mmHg)	31±5	17	36±3	30	0.298	12±3	21
Valsalva manoeuvre ratio	1.95±0.41	17	2.01±0.06	30	0.580	1.62±0.07	21
Cold pressor ΔSBP (mmHg)^†	20±2	17	20±2	29	1.000	20±3	20
LF_RRI (ms²)	371±92	17	564±97	30	0.293	921±161	22
HF_RRI (ms²)	322±109	17	338±58	30	0.598	1372±321	22
LF_RRI/HF_RRI	2.0±0.3	17	2.3±0.2	30	0.406	1.1±0.2	22
LF_SBP (mmHg²)	4.8±1.0	17	6.3±0.7	30	0.019	3.5±0.6	22
Plasma noradrenaline (pg/ml)
Supine	173±27	17	203±27	30	0.232	189±15	22
Upright	779±131	17	635±51	30	0.587	388±18	22

*HR changes (ΔHR) from supine to standing at the time of maximal orthostatic tolerance.

†BP and HR responses are given as the change (Δ) compared with baseline.

‡BP recovery from early to late phase II of the Valsalva manoeuvre.