Impact of pericardial effusion on cardiac mechanics in patients with dilated cardiomyopathy

Dilated cardiomyopathy (CDM) is a degenerative disease of the myocardium accompanied by left ventricular (LV) remodeling, resulting in an impaired pump performance. Differently, pericardial effusion (PE) is a liquid accumulation in the pericardial cavity, which may inhibit blood filling of heart chambers. Clinical evidence show that PE may improve pump performance in patients with CDM. Therefore, this study aims to assess wall stress and global function of patients with CDM, PE as compared to healthy patient. These findings suggests that CDM has an important implication in the mechanical changes of LV and right ventricle by increasing wall stress and reducing pump function. Conversely, PE determines lowering myocardial fiber stress and improves global function as compared to those of CD

Reduction In body weight is an independent risk factor for mortality in chronic heart failure. Insights from GISSI-HF and Val-HeFT trials

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Evaluation of ventricular wall stress and cardiac function in patients with dilated cardiomyopathy

Dilated cardiomyopathy is a heart disease characterized by both left ventricular dilatation and left ventricular systolic dysfunction, leading to cardiac remodeling and ultimately heart failure. We aimed to investigate the effect of dilated cardiomyopathy on the pump performance and myocardial wall mechanics using patient-specific finite element analysis. Results evinced pronounced end-systolic wall stress on left ventricular wall of patients with dilated cardiomyopathy as compared to that of normal hearts. In dilated cardiomyopathy, both end-diastolic and end-systolic pressure-volume relationships of left ventricle and right ventricle were shifted to the right compared to controls, suggesting reduced myocardial contractility. We hereby propose that finite element analysis represents a useful tool to assess the myocardial wall stress and cardiac work, which are responsible for progressive left ventricular deterioration and poor clinical course

Biomechanical implications of excessive endograft protrusion into the aortic arch after thoracic endovascular repair

Endografts placed in the aorta for thoracic endovascular aortic repair (TEVAR) may determine malappositioning to the lesser curvature of the aortic wall, thus resulting in a devastating complication known as endograft collapse. This premature device failure commonly occurs in young individuals after TEVAR for traumatic aortic injuries as a result of applications outside the physical conditions for which the endograft was designed. In this study, an experimentally-calibrated fluid-structure interaction (FSI) model was developed to assess the hemodynamic and stress/strain distributions acting on the excessive protrusion extension (PE) of endografts deployed in four young patients underwent TEVAR. Endograft infolding was experimentally measured for different hemodynamic scenarios by perfusion testing and then used to numerically calibrate the mechanical behavior of endograft PE. Results evinced that the extent of endograft can severely alter the hemodynamic and structural loads exerted on the endograft PE. Specifically, PE determined a physiological aortic coarctation into the aortic arch characterized by a helical flow in the distal descending aorta. High device displacement and transmural pressure across the stent-graft wall were found for a PE longer than 21 mm. Finally, marked intramural stress and principal strain distributions on the protruded segment of the endograft wall may suggest failure due to material fatigue. These critical parameters may contribute to the endograft collapse observed clinically and can be used to design new devices more suitable for young individuals to be treated with an endoprosthesis for TEVAR of blunt traumatic aortic injuries

The interpreters' point of view on ELF at the European Commission: "a completely uneven playing field"

The use of English as a Lingua Franca is a promising solution to the overcoming of language barriers in a wide variety of contexts and, despite being formally governed by the principle of multilingualism, the European institutions are no exception. This paper aims at shedding light on the perception on the use of ELF within the European Commission, by presenting the results of a questionnaire carried out within the framework of a broader PhD project. The target population is that of interpreters working for the European Commission. The analysis focuses on two specific questions, which address interpreters in their role as communication experts, inviting them to momentarily set aside their opinion on the relationship between ELF and interpretation and rather assess ELF in terms of "communicative effectiveness,"considered as an essential component to a successful communication. Results confirm previous ITELF (Interpreting, Translation and English as a Lingua Franca) studies, in that interpreters believe that ELF tends to decrease the level of communicative effectiveness and that, based on their direct experience, less than half of the speakers in these meetings succeed at expressing themselves effectively when using ELF. Most importantly, they elaborate on what this loss of effectiveness entails in terms of communication quality, interlocutors' participation rights and multilingualism

Impact Of Pericardial Effusion On Cardiac Mechanics In Patients With Dilated Cardiomyopathy

Dilated cardiomyopathy (CDM) is a degenerative disease of the myocardium accompanied by left ventricular (LV) remodeling, resulting in an impaired pump performance. Differently, pericardial effusion(PE) is a liquid accumulation in the pericardial cavity, which may inhibit blood filling of heart chambers. Clinical evidence show that PE may improve pump performance in patients with CDM. Therefore, this study aims to assess wall stress and global function of patients with CDM, PE as compared to healthy patient. These findings suggests that CDM has an important implication in the mechanical changes of LV and right ventricle by increasing wall stress and reducing pump function. Conversely, PE determines lowering myocardial fiber stress and improves global function as compared to those of CD

Mechanics of pericardial effusion: A simulation study

Pericardial effusion is a pathological accumulation of fluid within pericardial cavity, which may compress heart chambers with hemodynamic impairment. We sought to determine the mechanics underlying the physiology of the hemodynamic impairment due to pericardial effusion using patient-specific computational modeling. Computational models of left ventricle and right ventricle were based on magnetic resonance images obtained from patients with pericardial effusion and controls. Myocardial material parameters were adjusted, so that volumes of ventricular chambers and pericardial effusion agreed with magnetic resonance imaging data. End-diastolic and end-systolic pressure-volume relationships as well as stroke volume were determined to evaluate impaired cardiac function of biventricular model. Distributions of myocardial fiber stresses and their regional variation along left ventricular wall were compared between patient groups. Both end-diastolic and end-systolic pressure-volume relationships shifted to the left for patients with pericardial effusion, with right ventricle diastolic filling particularly restricted. Left ventricle function as estimated by Starling curve was reduced by pericardial effusion. End-systolic fiber stress of left ventricle was significantly reduced as compared to that found for healthy patients. Myocardial stress was found increased at interventricular septum when compared to that exerted at lateral wall of left ventricle. Right ventricular myocardial stress was reduced as a consequence of the pressure equalization between right ventricle and pericardial effusion. Diastolic right ventricle collapse in patients with pericardial effusion is related to higher myocardial fiber stress on interventricular septum and to an extensible pericardium reducing motion of ventricular chambers, with right ventricle particularly restrained. These findings likely portend progression of pericardial effusion to cardiac tamponade

Modelling cardiac mechanics of left ventricular noncompaction

Left ventricular noncompaction (LVNC) can be defined as a cardiomyopathy characterised by a pattern of prominent trabecular structure and deep intertrabecular recesses, that is thought to be caused by an arrest of normal endomyocardial morphogenesis. Using patient-specific computational modelling, we assessed the cardiac mechanics of five patients with LVNC and compared myocardial stress and pump performance to those of healthy controls. Findings shown that patients with LVNC have impaired left ventricular (LV) function, making it possible that the lack of fibre shortening of noncompacted layer can determine poor heart function. Pronounced end-systolic wall stress on left ventricular wall of patients with LVNC was observed when compared to that of normal hearts, and this may lead to adverse cardiac remodelling and ultimately heart failure. We hereby suggest that computational modelling can be considered as a useful tool to assess the cardiac work and pump performance of LVNC, which are responsible for progressive left ventricular deterioration and poor clinical course

An in vitro phantom study on the role of the bird-beak configuration in endograft infolding in the aortic arch

Purpose: To assess endograft infolding for excessive bird-beak configurations in the aortic arch in relation to hemodynamic variables by quantifying device displacement and rotation of oversized stent-grafts deployed in a phantom model. Methods: A patient-specific, compliant, phantom pulsatile flow model was reconstructed from a patient who presented with collapse of a Gore TAG thoracic endoprosthesis. Device infolding was measured under different flow and pressure conditions for 3 protrusion extensions (13, 19, and 24 mm) of the bird-beak configuration resulting from 2 TAG endografts with oversizing of 11% and 45%, respectively. Results: The bird-beak configuration with the greatest protrusion extension exhibited the maximum TAG device displacement (1.66 mm), while the lowest protrusion extension configuration led to the minimum amount of both displacement and rotation parameters (0.25 mm and 0.6°, respectively). A positive relationship was found between the infolding parameters and the flow circulating in the aorta and left subclavian artery. Similarly, TAG device displacement was positively and significantly (p<0.05) correlated with the pulse pressure for all bird-beak configurations and device sizes. However, no collapse was observed under chronic perfusion testing maintained for 30 days and pulse pressure of 100 mm Hg. Conclusion: These findings suggest that endograft infolding depends primarily on the amount of aortic pulsatility and flow rate and that physiological flows do not necessarily engender hemodynamic loads on the proximal bird-beak segment sufficient to cause TAG collapse. Hemodynamic variables may allow for identification of patients at high risk of endograft infolding and help guide preventive intervention to avert its occurrence