Table 1.

Comparative Echocardiographic Data Among the Study Groups

	CFSOI(+)	CFSOI(−)	OI	Controls
No. of patients	26	20	11	27
M/F	7/19	9/11	2/9	10/17
Age (y)	28 ± 8	32 ± 8	31 ± 7	32 ± 7
Cardiothoracic ratio (%)	38 ± 5a,b	42 ± 4	42 ± 3c	44 ± 4
Heart rate (bpm)	69 ± 15	72 ± 13	68 ± 11	70 ± 12
SBP (mm Hg)	109 ± 11a,b	115 ± 13	112 ± 14c	121 ± 11
DBP (mm Hg)	66 ± 12a,b	72 ± 12	68 ± 13c	75 ± 12
IVS (mm)	8 ± 1	9 ± 1	8 ± 1	9 ± 1
PW (mm)	8 ± 1	9 ± 1	8 ± 1	9 ± 1
LVEDD (mm)	39 ± 5b,d	45 ± 5	40 ± 5b,d	45 ± 4
LVEDD <40 (mm)	14 (54%)a,b	1 (5%)	5 (45%)a,b	1 (4%)
LVESD (mm)	25 ± 5b,d	28 ± 3	24 ± 5b,d	27 ± 2
LAD (mm)	25 ± 5	27 ± 5	24 ± 4	27 ± 4
AoD (mm)	26 ± 4	26 ± 4	25 ± 3	27 ± 5
RVD (mm)	15 ± 4	17 ± 4	15 ± 2	15 ± 3
Stroke volume (mL)	45 ± 13b,d	64 ± 17	49 ± 11a,b	63 ± 13
Stroke volume index (mL/m2)	30 ± 7b,d	38 ± 7	33 ± 7c	39 ± 7
Cardiac output (L/min)	3.0 ± 0.7b,d	4.5 ± 1.1	3.3 ± 1.0b,d	4.4 ± 1.0
Cardiac index (L/min/m2)	2.0 ± 0.3b,d	2.7 ± 0.6	2.2 ± 0.5a,c	2.7 ± 0.6
Cardiac index <2 (L/min/m2)	17 (65%)b,d	1 (5%)	3 (27%)	3 (11%)
Fractional shortening (%)	37 ± 4	38 ± 3	40 ± 7	39 ± 3
LVEF (%)	67 ± 5	68 ± 4	71 ± 8	69 ± 4
LV mass index (g/m2)	62 ± 16b,d	77 ± 14	64 ± 13a,c	77 ± 16

Abbreviations: AoD, aortic root diameter; CFSOI(+), patients with chronic fatigue syndrome and orthostatic intolerance; CFSOI(−), patients with chronic fatigue syndrome but without orthostatic intolerance; DBP, diastolic blood pressure; F, female; IVS, interventricular septum thickness; LAD, left atrial dimension; LV, left ventricular; LVEDD, left ventricular end‐diastolic dimension; LVEF, left ventricular ejection fraction; LVESD, left ventricular end‐systolic dimension; M, male; OI, patients with orthostatic intolerance but without chronic fatigue syndrome; PW, left ventricular posterior wall thickness; RVD, right ventricular dimension; SBP, systolic blood pressure.

^a P<0.05 vs CFSOI(−).

^b P<0.01 vs controls.

^c P<0.05 vs controls.

^d P<0.01 vs CFSOI (−).