Physiological Objectification of the Spread of Phase Trajectories of the Heart's Electrical Activity in a Digital ECG Research

The conducted studies have shown that the spread of ECG phase trajectories, recorded even in one (first standard) lead, carries additional diagnostic information about the level of adaptive reserves of the body and can be quantified by the
$\sigma \text{QRS}$
indicator. Quantitative changes in the
$\sigma \text{QRS}$
index either in case of urgent and long-term adaptation or in case of its failure are directly related to the optimal inclusion of high-frequency components of heart rate regulation and can be used as an additional criterion for assessing the functional state of the cardiovascular system