Wireless ECG and cardiac monitoring systems: State of the art, available commercial devices and useful electronic components

Abstract Wireless ElectroCardioGram (ECG) systems are employed in manifold application fields: tele-monitoring, sport applications, support to ageing people at home, fetal ECG, wearable devices and ambulatory monitoring. The presence of cables often hinders user’s free movements, alongside clinicians’ routine operations. Therefore, wireless ECG systems are desirable. This paper aims at reviewing the solutions described in the literature, besides commercially available devices and electronic components useful to setup laboratory prototypes. Several systems have been developed, different in terms of the adopted technology; when approaching the development of a wireless ECG system, some import…

Three-dimensional parametric modeling of bicuspid aortopathy and comparison with computational flow predictions

Bicuspid aortic valve (BAV)-associated ascending aneurysmal aortopathy (namely "bicuspid aortopathy") is a heterogeneous disease making surgeon predictions particularly challenging. Computational flow analysis can be used to evaluate the BAV-related hemodynamic disturbances, which likely lead to aneurysm enlargement and progression. However, the anatomic reconstruction process is time consuming so that predicting hemodynamic and structural evolution by computational modeling is unfeasible in routine clinical practice. The aim of the study was to design and develop a parametric program for three-dimensional (3D) representations of aneurysmal aorta and different BAV phenotypes starting from s…

Three-dimensional parametric modeling of bicuspid aortopathy and comparison with computational flow predictions

Bicuspid aortic valve (BAV)-associated ascending aneurysmal aortopathy (namely “bicuspid aortopathy”) is a heterogeneous disease making surgeon predictions particularly challenging. Computational flow analysis can be used to evaluate the BAV-related hemodynamic disturbances, which likely lead to aneurysm enlargement and progression. However, the anatomic reconstruction process is time consuming so that predicting hemodynamic and structural evolution by computational modeling is unfeasible in routine clinical practice. The aim of the study was to design and develop a parametric program for three-dimensional (3D) representations of aneurysmal aorta and different BAV phenotypes starting fr…

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 o…

Biomechanical Determinants of Right Ventricular Failure in Pulmonary Hypertension.

Pulmonary hypertension (PH) is a disease characterized by progressive adverse remodeling of the distal pulmonary arteries, resulting in elevated pulmonary vascular resistance and load pressure on the right ventricle (RV), ultimately leading to RV failure. Invasive hemodynamic testing is the gold standard for diagnosing PH and guiding patient therapy. We hypothesized that lumped-parameter and biventricular finite-element (FE) modeling may lead to noninvasive predictions of both PH-related hemodynamic and biomechanical parameters that induce PH. We created patient-specific biventricular FE models that characterize the biomechanical response of the heart and coupled them with a lumped-paramete…

Steam sterilization processes affect the stability of clinical thermometers: Thermistor and prototypal FBG probe comparison

Abstract Temperature is one of the most frequently measured physical quantities in clinical environment and a good biomarker of illness. The need for reusable probes, which have to be sterilized to prevent infections, requires the metrological qualification of thermometer probes in response to ageing effects induced by several sterilization processes. In this study, we investigated the effect of repeated sterilizations on both a commonly-used autoclavable thermistor probe and a prototypal Fiber Bragg Gratings (FBG) probe for temperature measurements. Findings highlighted a greater reliability of the proposed FBG probe than the commercial thermistor. Specifically, the FBG probe was able to w…

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, sugges…

Early distal remodeling after elephant trunk repair of thoraco-abdominal aortic aneurysms

Hemodynamic alterations occur when the elephant trunk (ET) technique is adopted to treat extensive aortic aneurysms. In planning the 2nd stage operation to complete ET repair, surgeons must weigh an adequate recovery time after initial surgery against the risk of postoperative ET-related complications. The purpose of this study was to understand the mechanistic link between the flow alteration caused by the ET graft and the development of premature aortic rupture before the 2nd stage operation. Specifically, fluid-structure interaction (FSI) analysis was performed using the CT imaging data of aorta at different stages of ET repair, and then computational variables were compared to those obs…

Shear stress alterations in the celiac trunk of patients with a continuous-flow left ventricular assist device as shown by in-silico and in-vitro flow analyses

Background The use of left ventricular assist devices (LVADs) to treat advanced cardiac heart failure is constantly increasing, although this device leads to high risk for gastrointestinal bleeding. Methods Using in-silico flow analysis, we quantified hemodynamic alterations due to continuous-flow LVAD (HeartWare, Inc., Framingham, MA) in the celiac trunk and major branches of the abdominal aorta, and then explored the relationship between wall shear stress (WSS) and celiac trunk orientation. To assess outflow from the aortic branch, a 3-dimensional-printed patient-specific model of the celiac trunk reconstructed from an LVAD-supported patient was used to estimate echocardiographic outflow …

Cardiac Mechanics of Left Ventricular NonCompaction by Finite Element Modeling

POLYSACCHARIDE-BASED HYDROGELS FOR MYOCARDIUM REMODELING

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 TE…

Computational modeling of bicuspid aortopathy: Towards personalized risk strategies.

This paper describes current advances on the application of in-silico for the understanding of bicuspid aortopathy and future perspectives of this technology on routine clinical care. This includes the impact that artificial intelligence can provide to develop computer-based clinical decision support system and that wearable sensors can offer to remotely monitor high-risk bicuspid aortic valve (BAV) patients. First, we discussed the benefit of computational modeling by providing tangible examples of in-silico software products based on computational fluid-dynamic (CFD) and finite-element method (FEM) that are currently transforming the way we diagnose and treat cardiovascular diseases. Then…

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 protr…

Particle image velocimetry study of the celiac trunk hemodynamic induced by continuous-flow left ventricular assist device

Abstract Whereas left ventricular assist device (LVAD) is the gold-standard therapy for patients with heart failure, gastrointestinal bleeding is one of the most common complications. LVAD implantation may remarkably impact aortic hemodynamics so that experimental and computational flow analyses can be used to study the disease mechanisms. Here we present an experimentally-calibrated computational model of the celiac trunk hemodynamic of a LVAD-supported patient who experienced bleeding after device implantation. Specifically, both particle image velocimetry (PIV) and echocardiography were used to measure and compare flow distributions in each branch of a phantom model of the patient abdomi…

STUDIO E VALIDAZIONE DI SISTEMI PER L’IDENTIFICAZIONE E IL MONITORAGGIO DI PARAMETRI BIOMEDICI ATTI ALLA PREVENZIONE DI EVENTI INDESIDERATI E ALL’ASSISTENZA DI INDIVIDUI CON DIVERSE TIPOLOGIE DI RISCHIO SANITARIO

L’aumento delle patologie cronico-degenerative nella popolazione mondiale ha comportato un numero sempre maggiore di individui richiedenti assistenza sanitaria, generando, nell’ambito delle realtà ospedaliere, diverse problematiche relative al miglioramento della qualità di vita dei pazienti, ai costi e alla gestione di un numero sempre crescente di soggetti ammalati. Il trattamento sanitario e la ricerca di base si sono pertanto orientati verso la prevenzione delle condizioni che predispongono i soggetti ai peggioramenti clinici e ai ricoveri ospedalieri, puntando sia su nuovi sistemi indossabili di monitoraggio per individuare precocemente i segni di peggioramento, sia su sistemi che poss…

Computational Fluid-Dynamic Analysis after Carotid Endarterectomy: Patch Graft versus Direct Suture Closure.

Background Closure technique after carotid endarterectomy (CEA) still remains an issue of debate. Routine use of patch graft (PG) has been advocated to reduce restenosis, stroke, and death, but its protective effect, particularly from late restenosis, is less evident and recent studies call into question this thesis. This study aims to compare PG and direct suture (DS) by means of computational fluid dynamics (CFD). To identify carotid regions with flow recirculation more prone to restenosis development, we analyzed time-averaged oscillatory shear index (OSI) and relative residence time (RRT), that are well-known indices correlated with plaque formation. Methods CFD was performed in 12 pati…

A study on the effect of contact pressure during physical activity on photoplethysmographic heart rate measurements

Heart rate (HR) as an important physiological indicator could properly describe global subject&rsquo

A preliminary investigation of the effect of contact pressure on the accuracy of heart rate monitoring by wearable PPG wrist band

The increase of safety and health monitor of workers has become a crucial objective to prevent excessive physical workloads, injuries, accidents and errors. Heart rate (HR) is a very important physiological indicator which could properly describe the workers’ physical status. Recently, wearable photoplethysmographic (PPG) wristband trackers have been utilized to measure HR without hindering normal gesture of workers. However, the quality of PPG signals is highly affected by human physical motions, resulting in a poor reliable HR estimation. Specifically, during different activities and gestures, PPG sensor contact pressures may have an impact on the quality of the heart rate signal. To appr…

Modeling Right Ventricle Failure After Continuous Flow Left Ventricular Assist Device: A Biventricular Finite-Element and Lumped-Parameter Analysis

The risk of right ventricle (RV) failure remains a major contraindication for continuous-flow left ventricular assist device (CF-LVAD) implantation in patients with heart failure. It is therefore critical to identify the patients who will benefit from early intervention to avoid adverse outcomes. We sought to advance the computational modeling description of the mechanisms underlying RV failure in LVAD-supported patients. RV failure was studied by computational modeling of hemodynamic and cardiac mechanics using lumped-parameter and biventricular finite element (FE) analysis. Findings were validated by comparison of bi-dimensional speckle-tracking echocardiographic strain assessment of the …

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 …