Table 2

Correlations between heart rate variability and the continuous explanatory variables

Explanatory variable	n	Correlation with HRV	p Value
Age	28	−0.472	0.011^*
Ejection fraction (LVEF)	28	0.144	0.465
Fractional shortening (LVFS)	28	−0.161	0.412
Right ventricular size (RVDd)	28	−0.464	0.013^*
Right ventricular pressure (RVp)	28	−0.432	0.022^*
QRS duration	28	0.060	0.763
LVEF by isotope scan	26	0.013	0.949
RVEF by isotope scan	26	0.050	0.807

There is a correlation between reduced heart rate variability and increasing age; reduced heart rate variability and increased right ventricular pressure; and reduced heart rate variability and increased right ventricular size.
HRV, heart rate variability; LVEF, left ventricular ejection fraction; LVFS, left ventricular fractional shortening; RVDd, right ventricular end diastolic dimension; RVEF, right ventricular ejection fraction.