Table 3.

Differences in the stroke volume index – heart rate correlation between healthy controls and ME/CFS patients and between supine and end-tilt.

Correlations supine healthy controls versus ME/CFS patients				Slope difference
Healthy Controls		ME/CFS patients		p-value
Correlation supine	R and p-value	Correlation supine	R and p-value
Y = −0,9769 *X + 99,18	0.52; < 0.0001	Y = −0,7510 *X + 97,86	0.42; < 0.0001	0.39
Correlations end-tilt healthy controls versus ME/CFS patients
Correlation end-tilt	R and p-value	Correlation end-tilt	R and p-value
Y = −1968 *X + 130,7	0.68; < 0.0001	Y = −1066 *X + 108,4	0.39; < 0.0001	0.0063

Correlations healthy controls: supine versus end-tilt				Slope difference
Supine		End-tilt		p-value
Correlation	R and p-value	Correlation	R and p-value
Y = −0,9769 *X + 99,18	0.52; < 0.0001	Y = −1968 *X + 130,7	0.68; < 0.0001	0.0095
Correlations ME/CFS patients: supine versus end-tilt
correlation	R and p-value	correlation	R and p-value
Y = −0,7510 *X + 97,86	0.42; < 0.0001	Y = −1066 *X + 108,4	0.39; < 0.0001	0.045

ME/CFS: myalgic encephalomyelitis. X = stroke volume index, Y = heart rate; A p-value of < 0.01 is considered statistically significant.