Dynamical Systems: Modelling by Jan Awrejcewicz

Author:Jan Awrejcewicz
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

2 Materials and Methods

A series of measurements has been carried out on a control group of young healthy volunteers (11 male, 14 female, age = 23 4 years). Arterial blood pressure curves P(t) in thoracic aorta , femoral and brachial arteries (both right and left) have been computed from the blood vessel oscillation curves measured by ultrasound scanner Elegra Advanced (Siemens). The procedure has been described in [3]. The group of patients with age-related cardiovascular diseases (hypertension, atherosclerosis, deep veins thrombosis) consisted of 12 males and 13 females (age = 64 6 years). The measured signals have been treated by Bayesian filter.

Heart rate variability and the phase curves , where have been studied. Some preliminary results of the study have been reported in [4]. Different types of the measured signals have been distinguished (Figs. 1, 2 and 3). The control group demonstrated regular dynamics with high synchronization of the blood pressure oscillations in aorta and peripheral arteries. The example is presented by the curves 1 () and 2 () in Fig. 1. The time shift between the peaks of the anacrotic and dicrotic waves in and is almost constant and the end-systolic and end-diastolic blood pressure decay at the same attenuation rate. This correspondence between the , and has been detected in 21 volunteers from the control group, while four others (two male and two female) exhibited a discordance between one of the or curves with others. For instance, the data presented in Fig. 1 show good correspondence between and while the curve possess earlier anacrotic peak provided by the higher pulse wave velocity due to the more rigid arterial walls and faster end-systolic and end-diastolic decay with a series of small amplitude peaks determined by the complex peripheral wave reflection and high compliance of the microcirculatory system. The reported discordance may serve as early index of developing vascular pathology in young individuals.

Fig. 1Pressure oscillations in the abdominal aorta (1), left (2) and right (3) femoral arteries in a healthy young volunteer

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