A beat-to-beat model of the cardiovascular system is developed to study the spontaneous short-term variability in arterial blood pressure (BP) and heart rate (HR) data from humans at rest. The model consists of a set of difference equations representing the following mechanisms: 1) control of HR and peripheral resistance by the baroreflex, 2) Windkessel properties of the systemic arterial tree,...

AIM To characterize the buffering function of the pulmonary artery in vivo and to determine the role of vascular smooth muscle (VSM) activation in vessel wall elasticity. MATERIAL AND METHOD Pulmonary artery pressure and diameter were measured in 9 anesthetized sheep. Pulmonary artery hypertension was induced by mechanical occlusion of the pulmonary artery and by phenylephrine infusion (5 mic...

Measuring the hemodynamic response with functional magnetic resonance imaging (fMRI) together with functional near-infrared spectroscopy (fNIRS) may overcome limitations of single-method approaches. Accordingly, we measured the event-related hemodynamic response with both imaging methods simultaneously in young subjects during visual stimulation. An intertrial interval of 60 s was chosen to inc...

Progression of carotid stenosis (CS) significantly reduces blood flow in the affected arteries and alters both proximal distal hemodynamics. While conventional studies consider only region for analysis, an extended larger arterial domain aortic–cerebral vasculature is used to avoid artificial modeling inlet condition facilitate automatic redistribution during CS progression. The fluid was const...

Central blood pressure, i.e., the pressure near heart, is an important physiological indicator of cardiovascular function a patient. However, direct measurement this quantity rarely carried out due to invasive nature procedure. Instead, at arm (brachial artery) measured through inflatable cuff commonly used represent or estimate central pressure. On other hand, aortic propagates downstream in f...

teleosts is due to the presence of a large central compliance that is the product of elastic and resistive elements downstream of the heart. While the resistance of the gills is only about 30–50% of the total peripheral resistance, the ventral aorta and branchial arteries are short, resulting in a small total compliance of the central arterial circulation. The bulbus arteriosus, the most anteri...

teleosts is due to the presence of a large central compliance that is the product of elastic and resistive elements downstream of the heart. While the resistance of the gills is only about 30–50% of the total peripheral resistance, the ventral aorta and branchial arteries are short, resulting in a small total compliance of the central arterial circulation. The bulbus arteriosus, the most anteri...

OBJECTIVE Personalized external aortic root support (PEARS) is a novel surgical approach with the aim of stabilizing the aortic root size and decreasing risk of dissection in Marfan syndrome patients. A bespoke polymer mesh tailored to each patient's individual aorta shape is produced by modeling and then surgically implanted. The aim of this study is to assess the mechanical effects of PEARS o...

The aim of this study was to test whether the simple ratio of right ventricular (RV) end-systolic pressure (Pes) to stroke volume (SV), known as the effective arterial elastance (Ea), provides a valid assessment of pulmonary arterial load in case of pulmonary embolism- or endotoxin-induced pulmonary hypertension. Ventricular pressure-volume (PV) data (obtained with conductance catheters) and in...

OBJECTIVE The mechanism of sustained alterations in pulmonary hemodynamics during endotoxin shock remains unclear. To gain more detailed knowledge we used the four-element windkessel model as a descriptor of the pulmonary circuit. METHODS Consecutive changes in characteristic resistance (R1), vascular compliance (C), input resistance (R2) and inductance (L) were continuously assessed followin...