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Cardiac vortex

A M Bavo, A M Pouch, J Degroote, J Vierendeels, J H Gorman, R C Gorman, P Segers
BACKGROUND: The goal of this paper is to present a computational fluid dynamic (CFD) model with moving boundaries to study the intraventricular flows in a patient-specific framework. Starting from the segmentation of real-time transesophageal echocardiographic images, a CFD model including the complete left ventricle and the moving 3D mitral valve was realized. Their motion, known as a function of time from the segmented ultrasound images, was imposed as a boundary condition in an Arbitrary Lagrangian-Eulerian framework...
2016: Biomedical Engineering Online
Gert Reiter, Ursula Reiter, Gabor Kovacs, Gabriel Adelsmayr, Andreas Greiser, Aurelien F Stalder, Horst Olschewski, Michael Fuchsjäger
BACKGROUND: In patients with pulmonary hypertension (PH), duration of vortical blood flow along the main pulmonary artery enables estimation of the mean pulmonary arterial pressure (mPAP) non-invasively. It remains to date not known, if this method is applicable in patients with pulmonary arterial hypertension (PAH) and abnormal aortic-to-pulmonary shunting. CASE PRESENTATION: The present case analyzes the effect of a patent ductus arteriosus (PDA) on pulmonary artery flow patterns in PAH (mPAP from right heart catheterization, 75 mmHg)...
2016: BMC Medical Imaging
Boyang Su, Ru San Tan, Ju Le Tan, Kenneth Wei Qiang Guo, Jun Mei Zhang, Shuang Leng, Xiaodan Zhao, John Carson Allen, Liang Zhong
Recent numerical studies were focused on the modeling of flow in patient-specific left ventricle (LV); however, the mitral valve (MV) was usually excluded. In this study, both patient-specific LV and MV were modeled to achieve a more realistic intraventricular flow. Cardiac MRI images were acquired from a pulmonary arterial hypertension (PAH) patient and a healthy volunteer, and manual segmentation was conducted to reconstruct three-dimensional (3D) LV and MV geometries at each frame. Based on these 3D geometries, vortex formation time (VFT) was derived, and the values were 4...
May 3, 2016: Journal of Biomechanics
Tomohiro Otani, Abdullah Al-Issa, Amir Pourmorteza, Elliot R McVeigh, Shigeo Wada, Hiroshi Ashikaga
Atrial fibrillation (AF), the most common human arrhythmia, is a marker of an increased risk of embolic stroke. However, recent studies suggest that AF may not be mechanistically responsible for the stroke events. An alternative explanation for the mechanism of intracardiac thrombosis and stroke in patients with AF is structural remodeling of the left atrium (LA). Nevertheless, a mechanistic link between LA structural remodeling and intracardiac thrombosis is unclear, because there is no clinically feasible methodology to evaluate the complex relationship between these two phenomena in individual patients...
March 11, 2016: Annals of Biomedical Engineering
Emre Gürel, Christian Prinz, Lieve Van Casteren, Hang Gao, Rik Willems, Jens-Uwe Voigt
BACKGROUND: The aims of this study were to assess the influence of left bundle branch block (LBBB)-like conduction abnormalities on left ventricular (LV) blood flow patterns and to characterize their potential impact on LV efficiency by measuring the changes in vortex formation and energy dissipation in the left ventricle using echocardiographic particle image velocimetry. METHODS: Thirty-six subjects were prospectively studied, including 20 patients with pacemakers, six patients with LBBB, and 10 healthy control subjects, all of whom had normal ejection fractions (>50%)...
May 2016: Journal of the American Society of Echocardiography
Per M Arvidsson, Sándor J Kovács, Johannes Töger, Rasmus Borgquist, Einar Heiberg, Marcus Carlsson, Håkan Arheden
The laws of fluid dynamics govern vortex ring formation and precede cardiac development by billions of years, suggesting that diastolic vortex ring formation is instrumental in defining the shape of the heart. Using novel and validated magnetic resonance imaging measurements, we show that the healthy left ventricle moves in tandem with the expanding vortex ring, indicating that cardiac form and function is epigenetically optimized to accommodate vortex ring formation for volume pumping. Healthy hearts demonstrate a strong coupling between vortex and cardiac volumes (R(2) = 0...
2016: Scientific Reports
Arvind Santhanakrishnan, Ikechukwu Okafor, Gautam Kumar, Ajit P Yoganathan
Diastolic fluid dynamics in the left ventricle (LV) has been examined in multiple clinical studies for understanding cardiac function in healthy humans and developing diagnostic measures in disease conditions. The question of how intraventricular filling vortex flow pattern is affected by increasing heart rate (HR) is still unanswered. Previous studies on healthy subjects have shown a correlation between increasing HR and diminished E/A ratio of transmitral peak velocities during early filling (E-wave) to atrial systole (A-wave)...
February 29, 2016: Journal of Biomechanics
S V Frolov, S V Sindeev, D Liepsch, A Balasso
BACKGROUND: According to the clinical data, flow conditions play a major role in the genesis of intracranial aneurysms. The disorder of the flow structure is the cause of damage of the inner layer of the vessel wall, which leads to the development of cerebral aneurysms. Knowledge of the alteration of the flow field in the aneurysm region is important for treatment. OBJECTIVE: The aim is to study quantitatively the flow structure in an patient-specific aneurysm model of the internal carotid artery using both experimental and computational fluid dynamics (CFD) methods with Newtonian and non-Newtonian fluids...
May 18, 2016: Technology and Health Care: Official Journal of the European Society for Engineering and Medicine
Satoshi Numata, Keiichi Itatani, Keiichi Kanda, Kiyoshi Doi, Sachiko Yamazaki, Kazuki Morimoto, Kaichiro Manabe, Koki Ikemoto, Hitoshi Yaku
OBJECTIVES: To obtain predictive information regarding aortic disease, we evaluated how blood flow inside the aortic arch was influenced by thoracic aortic aneurysms. In addition, to reveal the optimal intraoperative management in these cases, we examined blood flow during right subclavian arterial (rSCA) perfusion using computational fluid dynamics (CFD). METHODS: Patient-specific models of the aortic arch were made with six different patterns based on the computed tomographic images...
June 2016: European Journal of Cardio-thoracic Surgery
Mikael Kanski, Per M Arvidsson, Johannes Töger, Rasmus Borgquist, Einar Heiberg, Marcus Carlsson, Håkan Arheden
BACKGROUND: Measurement of intracardiac kinetic energy (KE) provides new insights into cardiac hemodynamics and may improve assessment and understanding of heart failure. We therefore aimed to investigate left ventricular (LV) KE time curves in patients with heart failure and in controls. METHODS: Patients with heart failure (n = 29, NYHA class I-IV) and controls (n = 12) underwent cardiovascular magnetic resonance (CMR) including 4D flow. The vortex-ring boundary was computed using Lagrangian coherent structures...
2015: Journal of Cardiovascular Magnetic Resonance
Vinh-Tan Nguyen, Stella Nathania Wibowo, Yue An Leow, Hoang-Huy Nguyen, Zhong Liang, Hwa Liang Leo
This work presents a computational fluid dynamic (CFD) model to simulate blood flows through the human heart's left ventricles (LV), providing patient-specific time-dependent hemodynamic characteristics from reconstructed MRI scans of LV. These types of blood flow visualization can be of great asset to the medical field helping medical practitioners better predict the existence of any abnormalities in the patient, hence offer an appropriate treatment. The methodology employed in this work processed geometries obtained from MRI scans of patient-specific LV throughout a cardiac cycle using computer-aided design tool...
December 2015: Cardiovascular Engineering and Technology
Hiroki Takahashi, Hideyuki Hasegawa, Hiroshi Kanai
PURPOSE: Ultrasonic imaging of blood flow in the cardiac lumen is a very useful tool to evaluate the pumping function of the human heart. The speckle tracking technique makes it possible to estimate the blood velocity vector. However, a stable estimation of the velocity vector of blood flow is difficult because signal-to-noise ratios of echoes from tiny blood particles are low. In this study, the speckle tracking technique with averaging of multiple two-dimensional correlation functions was employed for stable estimation of the blood velocity vector...
July 2015: Journal of Medical Ultrasonics
K Steding-Ehrenborg, P M Arvidsson, J Töger, M Rydberg, E Heiberg, M Carlsson, H Arheden
The kinetic energy (KE) of intracardiac blood may play an important role in cardiac function. The aims of the present study were to 1) quantify and investigate the determinants of KE, 2) compare the KE expenditure of intracardiac blood between athletes and control subjects, and 3) quantify the amount of KE inside and outside the diastolic vortex. Fourteen athletes and fourteen volunteers underwent cardiac MRI, including four-dimensional phase-contrast sequences. KE was quantified in four chambers, and energy expenditure was calculated by determining the mean KE/cardiac index...
January 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Jochen von Spiczak, Gerard Crelier, Daniel Giese, Sebastian Kozerke, David Maintz, Alexander Christian Bunck
INTRODUCTION: Phase contrast MRI allows for the examination of complex hemodynamics in the heart and adjacent great vessels. Vortex flow patterns seem to play an important role in certain vascular pathologies. We propose two- and three-dimensional metrics for the objective quantification of aortic vortex blood flow in 4D phase contrast MRI. MATERIALS AND METHODS: For two-dimensional vorticity assessment, a standardized set of 6 regions-of-interest (ROIs) was defined throughout the course of the aorta...
2015: PloS One
David M Overman
No abstract text is available yet for this article.
November 2015: Journal of Thoracic and Cardiovascular Surgery
Emmeline E Calkoen, Mohammed S M Elbaz, Jos J M Westenberg, Lucia J M Kroft, Mark G Hazekamp, Arno A W Roest, Rob J van der Geest
OBJECTIVES: During normal left ventricular (LV) filling, a vortex ring structure is formed distal to the left atrioventricular valve (LAVV). Vortex structures contribute to efficient flow organization. We aimed to investigate whether LAVV abnormality in patients with a corrected atrioventricular septal defect (AVSD) has an impact on vortex ring formation. METHODS: Whole-heart 4D flow MRI was performed in 32 patients (age: 26 ± 12 years), and 30 healthy subjects (age: 25 ± 14 years)...
November 2015: Journal of Thoracic and Cardiovascular Surgery
Brett E Fenster, James Browning, Joyce D Schroeder, Michal Schafer, Chris A Podgorski, Jamie Smyser, Lori J Silveira, J Kern Buckner, Jean R Hertzberg
Right ventricular diastolic dysfunction (RVDD) is an important prognostic indicator in pulmonary arterial hypertension (PAH). RV vortex rings have been observed in healthy subjects, but their significance in RVDD is unknown. Vorticity, the local spinning motion of an element of fluid, may be a sensitive measure of RV vortex dynamics. Using four-dimensional (4D) flow cardiac magnetic resonance imaging (CMR), we investigated the relationship between right heart vorticity with echocardiographic indexes of RVDD...
September 15, 2015: American Journal of Physiology. Heart and Circulatory Physiology
Bin-Yu Zhou, Jing Wang, Ming-Xing Xie, Man-Wei Liu, Qing Lv
Intraventricular hydrodynamics is considered an important component of cardiac function assessment. Vector flow mapping (VFM) is a novel flow visualization method to describe cardiac pathophysiological condition. This study examined use of new VFM and flow field for assessment of left ventricular (LV) systolic hemodynamics in patients with simple hyperthyroidism (HT). Thirty-seven simple HT patients were enrolled as HT group, and 38 gender- and age-matched healthy volunteers as control group. VFM model was used to analyze LV flow field at LV apical long-axis view...
August 2015: Journal of Huazhong University of Science and Technology. Medical Sciences
Fang Yang, Robert L Kormos, James F Antaki
OBJECTIVE: To investigate potentially prothrombotic flow patterns within an axial flow ventricular assist device under clinically relevant pulsatile hemodynamic conditions. METHODS: A transparent replica of the HeartMate-II left ventricular assist device (Thoratec, Pleasanton, Calif) was visualized using a high speed camera at both low and high frame rates (125 and 3000 fps). Three steady-state conditions were studied: nominal (4.5 lpm), low flow (3.0 lpm), and high flow (6...
October 2015: Journal of Thoracic and Cardiovascular Surgery
Gautam Kumar, Vrishank Raghav, Stamatios Lerakis, Ajit P Yoganathan
BACKGROUND AND AIM OF THE STUDY: Transcatheter aortic valve replacements (TAVRs) are performed using fluoroscopic guidance, which makes precise positioning challenging. The aim of the present study was to investigate the effect of TAV positioning on flow characteristics in the ascending aorta and sinuses. METHODS: A commonly used TAV design with a supra-annular support section was investigated using particle image velocimetry (PIV) under physiological flow and pressure conditions...
January 2015: Journal of Heart Valve Disease
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