The carried out research has included 50 children: I group (bisoprolol)-60% children and II group (placebo) - 40.0%, average age (13.5±0.60) years; doses of bisoprolol (PO): 1.25–2.5mg/kg/dose.
ECG monitoring has defined heart rate average maximum and minimum value in the beginning of research and in dynamics a month later. Dynamics in a month of action of a bisoprolol has not changed the minimum values of heart rate in the first group in comparison with placebo (p>0.05), but has lowered the maximum values of heart rate reductions at children with MVP (–8.74; p<0.01) in the first group in comparison with placebo (0.55; p>0.05) and average values of heart rate (–4.70; p<0,001) in the first group in comparison with placebo (–0.10; p>0.05). Statistical parametres HRV (SDNN and PNN 50) defined in the beginning in both groups did not differ considerably (p>0.05). Dynamics in a month of action bisoprolol on indicators HRV was showed by decrease in value PNN 50 in the first group (–6.42; p<0,001).
Results of research have revealed, that at children with MVP, bisoprolol has considerably reduced heart rate (–8.9; p<0,001) in comparison with placebo, without influence on systolic and diastolic blood pressure. Influence bisoprolol on indicators HRV in the first group it was characterised by decrease of statistics PNN 50 characteristic for activity of sympathetic vegetative nervous system (–6.42; p<0,001).