scholarly journals Flow Dynamics in a Model of a Left Ventricle with Different Mitral Valve Orientations

Fluids ◽  
2021 ◽  
Vol 6 (12) ◽  
pp. 428
Author(s):  
Ghassan Maraouch ◽  
Lyes Kadem
Keyword(s):  
Energy Dissipation ◽  
Mitral Valve ◽  
Left Ventricle ◽  
Residence Time ◽  
Flow Dynamics ◽  
Vortex Rings ◽  
Lagrangian Analysis ◽  
Particle Residence Time ◽  
Ventricle Volume ◽  
Different Levels

The formation of vortex rings at valve leaflets during ventricular inflow has been a topic of interest for many years. It is generally accepted nowadays that the purpose of vortex rings is to conserve energy, reduce the workload on the heart, and minimize particle residence time. We investigated these claims by testing three different levels of annulus angle for the mitral valve: a healthy case, a slightly angled case (20°), and a highly angled case (46°). Circulation was determined to be reversed in the non-healthy case, with a dominant counterclockwise rotation instead of clockwise. Viscous energy dissipation was highest in the slightly angled case, followed by the healthy case and then the highly angled case. A Lagrangian analysis demonstrated that the healthy case resulted in the least amount of stasis, requiring eight cardiac cycles to evacuate 99% of initial ventricle volume compared to the 16 and 13 cardiac cycles required by the slightly angled and highly angled cases, respectively.

On the Interaction of Natural and Mechanical Heart Valve Leaflets With the Chordae Tendineae

2002 ◽  
Author(s):  
Amber R. Mace ◽  
Pavlos P. Vlachos ◽  
Demetri P. Telionis
Keyword(s):  
Mitral Valve ◽  
Left Ventricle ◽  
Mechanical Heart Valve ◽  
Postoperative Mortality ◽  
Decisive Role ◽  
Flow Dynamics ◽  
Papillary Muscles ◽  
Posterior Leaflet ◽  
Chordae Tendineae ◽  
Atrioventricular Ring

Long before mitral valve replacement (MVR) became a routine operation, physiologic studies indicated that the continuity of mitral leaflets with papillary muscles, chordae tendineae (CT) and the atrioventricular ring may play a decisive role in the function of the left ventricle (LV) [1]. This led Lillehei et al. [2] to establish a procedure whereby the posterior leaflet, its CT and papillary muscles were preserved in MVRs. These and other studies indicated a significant reduction of postoperative mortality compared to conventional MVR. Though developed in the early 1960s by Lillehei, the technique of chordal preservation was not initially accepted. It wasn’t until 1983 that surgeons began to revive the concept of MVR with preservation of the CT. As this technique became more widely known, many clinical studies were performed; however, very few have been conducted which examine the effect of leaflets and CT on flow dynamics.

Extended Myectomy for Hypertrophic Obstructive Cardiomyopathy

2012 ◽  
Vol 15 (5) ◽  
pp. 251
Author(s):  
Changqing Gao ◽  
Chonglei Ren ◽  
Cangsong Xiao ◽  
Yang Wu ◽  
Gang Wang ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Left Ventricle ◽  
Mitral Regurgitation ◽  
Surgical Procedures ◽  
Hypertrophic Obstructive Cardiomyopathy ◽  
Systolic Anterior Motion ◽  
Anterior Leaflet ◽  
Septal Myectomy ◽  
The Mean

<p><b>Background:</b> The purpose of this study was to summarize our experience of extended ventricular septal myectomy in patients with hypertrophic obstructive cardiomyopathy (HOCM).</p><p><b>Methods:</b> Thirty-eight patients (26 men, 12 women) with HOCM underwent extended ventricular septal myectomy. The mean age was 36.3 years (range, 18-64 years). Diagnosis was made by echocardiography. The mean (mean � SE) systolic gradient between the left ventricle (LV) and the aorta was 89.3 � 31.1 mm Hg (range, 50-184 mm Hg) according to echocardiographic assessments before the operations. Moderate or severe systolic anterior motion (SAM) of the anterior leaflet of the mitral valve was found in 38 cases, and mitral regurgitation was present in 29 cases. Extended ventricular septal myectomy was performed in all 38 cases. The results of the surgical procedures were evaluated intraoperatively with transesophageal echocardiography (TEE) and with transthoracic echocardiography (TTE) at 1 to 2 weeks after the operation. All patients were followed up with TTE after their operation.</p><p><b>Results:</b> All patients were discharged without complications. The TEE evaluations showed that the mean systolic gradient between the LV and the aorta decreased from 94.8 � 35.6 mm Hg preoperatively to 13.6 � 10.8 mm Hg postoperatively (<i>P</i> = .0000) and that the mean thickness of the ventricular septum decreased from 28.3 � 7.9 mm to 11.8 � 3.2 mm (<i>P</i> = .0000). Mitral regurgitation and SAM were significantly reduced or eliminated. During the follow-up, all patients promptly became completely asymptomatic or complained of mild effort dyspnea only, and syncope was abolished. TTE examinations showed that the postoperative pressure gradient either remained the same or diminished.</p><p><b>Conclusions:</b> Extended ventricular septal myectomy is mostly an effective method for patients with HOCM, and good surgical exposure and thorough excision of the hypertrophic septum are of paramount importance for a successful surgery.</p>

Effect of Particle Residence Time on Particle Dispersion in a Plane Mixing Layer

1993 ◽  
Vol 115 (4) ◽  
pp. 751-759 ◽  
Author(s):  
Tsuneaki Ishima ◽  
Koichi Hishida ◽  
Masanobu Maeda
Keyword(s):  
Gas Phase ◽  
Residence Time ◽  
Time Scale ◽  
Characteristic Time ◽  
Mixing Layer ◽  
Particle Dispersion ◽  
Laser Doppler Velocimeter ◽  
Characteristic Time Scale ◽  
Two Phase ◽  
Particle Residence Time

A particle dispersion has been experimentally investigated in a two-dimensional mixing layer with a large relative velocity between particle and gas-phase in order to clarify the effect of particle residence time on particle dispersion. Spherical glass particles 42, 72, and 135 μm in diameter were loaded directly into the origin of the shear layer. Particle number density and the velocities of both particle and gas phase were measured by a laser Doppler velocimeter with modified signal processing for two-phase flow. The results confirmed that the characteristic time scale of the coherent eddy apparently became equivalent to a shorter characteristic time scale due to a less residence time. The particle dispersion coefficients were well correlated to the extended Stokes number defined as the ratio of the particle relaxation time to the substantial eddy characteristic time scale which was evaluated by taking account of the particle residence time.

Left ventricle enlargement and increased systolic velocity in the mitral valve are indirect markers of the hepatopulmonary syndrome

2011 ◽  
Vol 31 (9) ◽  
pp. 1388-1394 ◽  
Author(s):  
Sophia Pouriki ◽  
Alexandra Alexopoulou ◽  
Christina Chrysochoou ◽  
Leonidas Raftopoulos ◽  
George Papatheodoridis ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Left Ventricle ◽  
Hepatopulmonary Syndrome
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