Read by QxMD icon Read

Fluid dynamics of the heart

Anirban Som, Souvik Maitra, Sulagna Bhattacharjee, Dalim K Baidya
BACKGROUND AND AIMS: Optimum perioperative fluid administration may improve postoperative outcome after major surgery. This meta-analysis and systematic review has been aimed to determine the effect of dynamic goal directed fluid therapy (GDFT) on postoperative morbidity and mortality in non-cardiac surgical patients. MATERIAL AND METHODS: Meta-analysis of published prospective randomized controlled trials where GDFT based on non-invasive flow based hemodynamic measurement has been compared with a standard care...
October 13, 2016: Journal of Anesthesia
Hadi Wiputra, Chang Quan Lai, Guat Ling Lim, Joel Jia Wei Heng, Lan Guo, Hwa Liang Leo, Sanah Merchant Soomar, Arijit Biswas, Citra Nurfarah Zaini Mattar, Choon Hwai Yap
0.6-1.9% of US children were born with congenital heart malformations. Clinical and animal studies suggests that abnormal blood flow forces might play a role in causing these malformation, highlighting the importance of understanding the fetal cardiovascular fluid mechanics. We performed Computational Fluid Dynamics simulations of the right ventricles, based on 4D ultrasound scans of three 20 weeks old normal human foetuses, to characterize their flow and energy dynamics. Peak intraventricular pressure gradients were found to be 0...
September 23, 2016: American Journal of Physiology. Heart and Circulatory Physiology
David H MacIver, Ismail Adeniran, Iain R MacIver, Alistair Revell, Henggui Zhang
Pulmonary hypertension is usually related to obstruction of pulmonary blood flow at the level of the pulmonary arteries (eg, pulmonary embolus), pulmonary arterioles (idiopathic pulmonary hypertension), pulmonary veins (pulmonary venoocclusive disease) or mitral valve (mitral stenosis and regurgitation). Pulmonary hypertension is also observed in heart failure due to left ventricle myocardial diseases regardless of the ejection fraction. Pulmonary hypertension is often regarded as a passive response to the obstruction to pulmonary flow...
October 2016: American Heart Journal
Jonas Lantz, Lilian Henriksson, Anders Persson, Matts Karlsson, Tino Ebbers
Cardiac hemodynamics can be computed from medical imaging data, and results could potentially aid in cardiac diagnosis and treatment optimization. However, simulations are often based on simplified geometries, ignoring features such as papillary muscles and trabeculae due to their complex shape, limitations in image acquisitions, and challenges in computational modeling. This severely hampers the use of computational fluid dynamics in clinical practice. The overall aim of this study was to develop a novel numerical framework that incorporated these geometrical features...
September 12, 2016: Journal of Biomechanical Engineering
Maxim G Itkin, Francis X McCormack, Yoav Dori
RATIONALE: Plastic bronchitis is a condition characterized by expectoration of branching bronchial casts. Although the mechanism of cast formation in adults with plastic bronchitis remains poorly understood, abnormal pulmonary lymphatic flow resulting in molding of congealing lymphatic fluids in the airway has been documented as a cause of the disease in children with congenital heart disease. OBJECTIVES: To use advanced lymphatic imaging techniques, including dynamic contrast-enhanced magnetic resonance (MR) lymphangiography (DCMRL) and intranodal lymphangiography, to investigate the mechanism of cast formation in adult patients with plastic bronchitis, and to evaluate the therapeutic outcome of percutaneous lymphatic embolization for these patients...
October 2016: Annals of the American Thoracic Society
Siamak N Doost, Dhanjoo Ghista, Boyang Su, Liang Zhong, Yosry S Morsi
Cardiovascular disease (CVD), the leading cause of death today, incorporates a wide range of cardiovascular system malfunctions that affect heart functionality. It is believed that the hemodynamic loads exerted on the cardiovascular system, the left ventricle (LV) in particular, are the leading cause of CVD initiation and propagation. Moreover, it is believed that the diagnosis and prognosis of CVD at an early stage could reduce its high mortality and morbidity rate. Therefore, a set of robust clinical cardiovascular assessment tools has been introduced to compute the cardiovascular hemodynamics in order to provide useful insights to physicians to recognize indicators leading to CVD and also to aid the diagnosis of CVD...
2016: Biomedical Engineering Online
Stefania Scarsoglio, Andrea Saglietto, Fiorenzo Gaita, Luca Ridolfi, Matteo Anselmino
BACKGROUND: Although atrial fibrillation (AF), a common arrhythmia, frequently presents in patients with underlying valvular disease, its hemodynamic contributions are not fully understood. The present work aimed to computationally study how physical conditions imposed by pathologic valvular anatomy act on AF hemodynamics. METHODS: We simulated AF with different severity grades of left-sided valvular diseases and compared the cardiovascular effects that they exert during AF, compared to lone AF...
2016: PeerJ
Giordano Tasca, Riccardo Vismara, Andrea Mangini, Claudia Romagnoni, Monica Contino, Alberto Redaelli, Gianfranco Beniamino Fiore, Carlo Antona
BACKGROUND: Aortic valve replacement has evolved recently with the development of the sutureless bioprosthesis. One such valve is the Perceval bioprosthesis, which is built by mounting leaflets of bovine pericardium to a thin stent; this approach has the potential to provide an excellent fluid dynamic performance. We undertook an in vitro study to compare the hydrodynamic performance of the sutureless bioprosthesis with two standard pericardial stented bioprostheses (Crown and Magna)...
August 17, 2016: Annals of Thoracic Surgery
Joris Van Cauwenberge, Lasse Lovstakken, Solveig Fadnes, Alfonso Rodriguez-Molares, Jan Vierendeels, Patrick Segers, Abigail Swillens
Ultrafast vector flow imaging would benefit newborn patients with congenital heart disorders, but still requires thorough validation before translation to clinical practice. This study investigates 2D speckle tracking of intraventricular blood flow in neonates when transmitting diverging waves at ultrafast frame rate. Computational and in-vitro studies enabled us to quantify the performance and identify artefacts related to the flow and the imaging sequence. First, synthetic ultrasound images of a neonate's left ventricular flow pattern were obtained with the ultrasound simulator Field II by propagating point scatterers according to 3D intraventricular flow fields obtained with computational fluid dynamics (CFD)...
August 1, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Costantino Del Gaudio, Pier Luca Gasbarroni, Giovanni Paolo Romano
End-stage failing heart valves are currently replaced by mechanical or biological prostheses. Both types positively contribute to restore the physiological function of native valves, but a number of drawbacks limits the expected performances. In order to improve the outcome, tissue engineering can offer an alternative approach to design and fabricate innovative heart valves capable to support the requested function and to promote the formation of a novel, viable and correctly operating physiological structure...
December 2016: Journal of the Mechanical Behavior of Biomedical Materials
Johannes Wappenschmidt, Simon J Sonntag, Martin Buesen, Sascha Gross-Hardt, Tim Kaufmann, Thomas Schmitz-Rode, Ruediger Autschbach, Andreas Goetzenich
Mechanical circulatory support can maintain a sufficient blood circulation if the native heart is failing. The first implantable devices were displacement pumps with membranes. They were able to provide a sufficient blood flow, yet, were limited because of size and low durability. Rotary pumps have resolved these technical drawbacks, enabled a growing number of mechanical circulatory support therapy and a safer application. However, clinical complications like gastrointestinal bleeding, aortic insufficiency, thromboembolic complications, and impaired renal function are observed with their application...
July 27, 2016: Annals of Biomedical Engineering
Armand Mensen, Zhongxing Zhang, Ming Qi, Ramin Khatami
The integration of near-infrared spectroscopy and electroencephalography measures presents an ideal method to study the haemodynamics of sleep. While the cortical dynamics and neuro-modulating influences affecting the transition from wakefulness to sleep is well researched, the assumption has been that individual slow waves, the hallmark of deep sleep, are spontaneously occurring cortical events. By creating event-related potentials from the NIRS recording, time-locked to the onset of thousands of individual slow waves, we show the onset of slow waves is phase-locked to an ongoing oscillation in the NIRS recording...
2016: Scientific Reports
Joanna M Joly, Vera Bittner
Although differences diminish with age, outcomes are overall worse for women compared to men who present with suspected acute coronary syndrome. The reasons for this discrepancy are multifactorial, including sex-related differences in atherosclerosis biology and fluid dynamics, as well as a premature conclusion by providers that chest pain must be noncardiac in the absence of obstructive coronary artery disease. In this review of existing literature, we explore the diverse differential diagnosis in this unique set of patients...
September 2016: Current Cardiology Reports
Wayne L Miller
Volume regulation, assessment, and management remain basic issues in patients with heart failure. The discussion presented here is directed at opening a reassessment of the pathophysiology of congestion in congestive heart failure and the methods by which we determine volume overload status. Peer-reviewed historical and contemporary literatures are reviewed. Volume overload and fluid congestion remain primary issues for patients with chronic heart failure. The pathophysiology is complex, and the simple concept of intravascular fluid accumulation is not adequate...
August 2016: Circulation. Heart Failure
Bruno De Broca, Jeremie Garnier, Marc-Olivier Fischer, Thomas Archange, Julien Marc, Osama Abou-Arab, Hervé Dupont, Emmanuel Lorne, Pierre-Grégoire Guinot
During abdominal surgery, the use of protective ventilation with a low tidal volume, positive expiratory pressure (PEEP) and recruitment maneuvers (RMs) may limit the applicability of dynamic preload indices. The objective of the present study was to establish whether or not the variation in stroke volume (SV) during an RM could predict fluid responsiveness.We prospectively included patients receiving protective ventilation (tidal volume: 6 mL kg, PEEP: 5-7 cmH2O; RMs). Hemodynamic variables, such as heart rate, arterial pressure, SV, cardiac output (CO), respiratory variation in SV (ΔrespSV) and pulse pressure (ΔrespPP), and the variation in SV (ΔrecSV) as well as pulse pressure (ΔrecPP) during an RM were measured at baseline, at the end of the RM, and after fluid expansion...
July 2016: Medicine (Baltimore)
Yvan Mivelaz, Mande T Leung, Mary Terri Zadorsky, Astrid M De Souza, James E Potts, George G S Sandor
Using noninvasive techniques, we sought to assess arterial stiffness, impedance, hydraulic power, and efficiency in children with postoperative tetralogy of Fallot (TOF), coarctation of the aorta (COA), and transposition of the great arteries (TGAs). Results were compared with those of healthy peers. Fifty-five children with repaired congenital heart disease (24 TOFs, 20 COAs, and 11 TGAs) were compared with 55 age-matched control subjects (CTRL). Echocardiographic Doppler imaging and carotid artery applanation tonometry were preformed to measure aortic flow, dimensions, and calculate pulse wave velocity, vascular impedance and arterial stiffness indexes, hydraulic power (mean and total), and hydraulic efficiency (HE) which were calculated using standard fluid dynamics equations...
August 15, 2016: American Journal of Cardiology
Yage Zhang, Bin Gao, Chang Yu
Although a growing number of patients undergo LVAD implantation for heart failure treatment, thrombi are still the devastating complication for patients who used LVAD. LVAD outflow cannula location and thrombi generation sources were hypothesized to affect the thrombi distribution in the aorta. To test this hypothesis, numerical studies were conducted by using computational fluid dynamic (CFD) theory. Two anastomotic configurations, in which the LVAD outflow cannula is anastomosed to the anterior and lateral ascending aortic wall (named as anterior configurations and lateral configurations, respectively), are designed...
September 2016: Computer Methods and Programs in Biomedicine
Alfonso/A Roberto/R Martiniello, Gianni/G Pedrizzetti, Valter/V Bianchi, Giovanni/G Tonti, Antonio/A D'Onofrio, Pio/P Caso
BACKGROUND: The availability of pacing configurations offered by quadripolar left ventricular leads could improve patients' response to cardiac resynchronization therapy; however, the selection of an optimal setting remains a challenge. Echo-particle imaging velocimetry has shown that regional anomalies of synchrony/synergy of the left ventricle are related to the alteration, reduction, or suppression of the physiological intracavitary pressure gradients. These observations are also supported by several numerical models of the left ventricle that have shown the close relationship between wall motion abnormalities, change of intraventricular flow dynamics, and abnormal distribution of forces operating on the ventricular endocardium...
2016: Journal of Medical Case Reports
Hanieh Mirzaee, Thomas Henn, Mathias J Krause, Leonid Goubergrits, Christian Schumann, Mathias Neugebauer, Titus Kuehne, Tobias Preusser, Anja Hennemuth
PURPOSE: To introduce a scheme based on a recent technique in computational hemodynamics, known as the lattice Boltzmann methods (LBM), to noninvasively measure pressure gradients in patients with a coarctation of the aorta (CoA). To provide evidence on the accuracy of the proposed scheme, the computed pressure drop values are compared against those obtained using the reference standard method of catheterization. MATERIALS AND METHODS: Pre- and posttreatment LBM-based pressure gradients for 12 patients with CoA were simulated for the time point of peak systole using the open source library OpenLB...
July 7, 2016: Journal of Magnetic Resonance Imaging: JMRI
Laura Ellwein, Margaret M Samyn, Michael Danduran, Sheila Schindler-Ivens, Stacy Liebham, John F LaDisa
Image-based computational fluid dynamics (CFD) studies conducted at rest have shown that atherosclerotic plaque in the thoracic aorta (TA) correlates with adverse wall shear stress (WSS), but there is a paucity of such data under elevated flow conditions. We developed a pedaling exercise protocol to obtain phase contrast magnetic resonance imaging (PC-MRI) blood flow measurements in the TA and brachiocephalic arteries during three-tiered supine pedaling at 130, 150, and 170 % of resting heart rate (HR), and relate these measurements to non-invasive tissue oxygen saturation [Formula: see text] acquired by near-infrared spectroscopy (NIRS) while conducting the same protocol...
July 4, 2016: Biomechanics and Modeling in Mechanobiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"