HEART RATE VARIABILITY: CLINICAL OPPORTUNITIES AND CONTROL

The aim – to estimate the possibility of ultrashort heart rate variability (HRV) analysisusing photoplethysmography (PPG) with assessment of pulse rate variability (PRV)by means of a smartphone under stress tests and assessment of the Beck DepressionInventory.Material and methods. Thirty healthy medical student volunteers were divided into twogroups one group underwent HRV analysis at baseline and after physical exertion (n=15),while the other was assessed at baseline and after psycho- emotional stress using the«ECG For Everybody» program with 2-minute registration of HRV using a smartphonewith assessment of 17 HRV parameters and analysis of 6 main parameters (SDNN,RMSSD, PNN50, LF, HF, LF/HF and additionally TINN). Results. According to the results of the analysis of HRV changes during the use of PPG by means of a smartphone under stress- tests with an assessment of the increase in changes from the initial values (D%), diff erences in the direction of the RMSSD indicators were determined (the diff erence was Δ%1-2= –13.77% (p>0.2) for physical activity and Δ%1-2= –2.25% (p>0.5) for psycho- emotional activity), SDNN (Δ%1-2= –23.35% (p>0.5) and Δ%1-2= –0.21% (p>0.5), respectively), PNN50 (Δ%1-2= –27.76% (p>0.2) and Δ%1-2=+14.72% (p>0.2), respectively), LF (Δ%1-2=+8.55% (p>0.5) and Δ%1-2=+141.40% (p<0.05), respectively), HF (Δ%1-2= –40.99% (p>0.2) and 1%1-2=+98.65% (p<0.005), respectively), LF/ HF (Δ%1-2=+113.79% (p<0.05) and Δ%1-2=+66.08% (p<0.02), respectively), ΤΙΝΝ(Δ%1-2= –34.50% (p<0.05) and Δ%1-2= –16.81% (p>0.2), respectively), the relationship of the odds ratio for the association between SDNN reduction and the presence of depression on the Beck scale, which is equal to 4.0 (however, at p>0.1). . The use of two-minute HRV registration in our own study has determined that the most eff ective indicators for physical activity are LF/HF and TINN, which indicates the predominance of sympathetic activation. During psycho- emotional stress, signifi cant changes in LF and LF/HF indicate sympathetic circuit activation. It is important to note that in medical students, activation of the sympathetic circuit is observed for all studied indicators RMSSD, SDNN, pNN50, LF and HF with a signifi cant diff erence for LF/HF and TINN during physical activity. Psycho- emotional stress is associated with the variability in indicator direction of the studied indicators, but also indicates the activation of the sympathetic circuit.Conclusions. The use of a smartphone- based photoplethysmography for HRV analysis is eff ective. Instability of HRV balance during physical activity in medical students has been observed, which contributes to sympathetic nervous system activation. In a small number of observations, the tendency of activation of the sympathetic division under stress for HRV indicators such as RMSSD, SDNN, PNN50, LF and HF has been confi rmed, with a reliable distribution for LF/HF and TINN. Assessment of mental well-being according to the Beck Depression Scale indicates a tendency to reduce the SDNN indicator in the presence of depression according to this scale with an odds ratio of 4.0.