Heart rate variability and left ventricular mass in slim children and young adults with hypertension

Uncontrolled arterial hypertension brings direct and long-term sequelae in adult age, such as stroke, ischaemic heart disease with myocardial infarction, left ventricular hypertrophy or cardiac arrhythmia.

To assess heart rate variability (HRV) spectral parameters and left ventricular mass in slim children with arterial hypertension, and to search for correlations between these two parameters.

35 children aged 14.4+/-3.1 with idiopathic untreated arterial hypertension were enrolled. The control group included 30 age- and gender-matched healthy children (aged 14.1+/-2.9 years). In all analysed subjects an analysis of HRV parameters (high frequency (HF) and low frequency (LF) components) during 10-minute waking state and sleeping time was performed and left ventricular mass (LVM) as well as the left ventricular mass index (LVMI, g/m) were assessed based on echocardiographic measurements.

There was no difference in LF during the waking state and sleep HF between the two groups, whereas HF values during the waking state were significantly lower (p<0.05) in children with hypertension. The LF/HF index from both registration intervals was significantly higher in the group of children with hypertension. In children with hypertension, LVM and LVMI correlated significantly with LF (r=0.32, p<0.05 and r=0.39, p<0.01). LVM and LVMI correlated positively with the LF/HF index during night hours (r=0.45, p<0.004 and r=0.49, p<0.002). No significant correlations were found between the analysed parameters in children from the control group.

The increase of sympathetic activity during sleep correlates significantly with left ventricular mass and corrected left ventricular mass index in children with arterial hypertension.