Małgorzata Andrzejewska
supervisor: Jan Żebrowski
Energy dispersal in real systems leads to irreversibility of processes in the time-domain. Entropy can be understood as a measure of the process of energy dissipation, and, therefore, a greater entropy is synonymous with a greater energy dispersal, a greater disorder. Production of entropy in an organism can be used to assess homeostasis. Gradients of various quantities related to metabolism arise in the body, which affects the rate of entropy production in the system. Entropy production is associated with irreversibility of processes. The aim of the planned research includes the study of the characteristics of irreversibility in time series of physiological signals, in particular those from the cardiovascular system. The main goal is to create new diagnostic methods for the human blood circulation system. To achieve that, measures of complexity, non-stationarity and multi-scale methods are used. During presentation the results of applying the concept of irreversibility to the study of repolarization in the ventricles will be presented using Horizontal Visibility Graph methods. We focused on the comparison of the nighttime recordings between healthy and patients with the LQTS1 syndrome. We obtained a statistically significant difference between those groups in time irreversibility of QT intervals. I will also present my current research objective which includes the analysis of asymptomatic COVID-19 patients about a fortnight after their being declared convalescent.