Using Position‐Based Dynamics for Simulating Mitral Valve Closure and Repair Procedures

Background : Many diseases that affect the mitral valve are accompanied by the proliferation or degradation of tissue microstructure. The early acoustic detection of these changes may lead to the better management of mitral valve disease. In this study, we examine the nonstationary acoustic effects of perturbing material parameters that characterize mitral valve tissue in terms of its microstructural components. Specifically, we examine the influence of the volume fraction, stiffness and splay of collagen fibers as well as the stiffness of the nonlinear matrix in which they are embedded. Methods and Results: To model the transient vibrations of the mitral valve apparatus bathed in a blood medium, we have constructed a dynamic nonlinear fluid-coupled finite element model of the valve leaflets and chordae tendinae. The material behavior for the leaflets is based on an experimentally derived structural constitutive equation. The gross movement and small-scale acoustic vibrations of the valvular structures result from the application of physiologic pressure loads. Material changes that preserved the anisotropy of the valve leaflets were found to preserve valvular function. By contrast, material changes that altered the anisotropy of the valve were found to profoundly alter valvular function. These changes were manifest in the acoustic signatures of the valve closure sounds. Abnormally, stiffened valves closed more slowly and were accompanied by lower peak frequencies. Conclusion: The relationship between stiffness and frequency, though never documented in a native mitral valve, has been an axiom of heart sounds research. We find that the relationship is more subtle and that increases in stiffness may lead to either increases or decreases in peak frequency depending on their relationship to valvular function.

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Abstract 1606: High Specificity of Prolonged Isovolumic Contraction Time for Reverse Remodeling Associated with Cardiac Resynchronization Therapy

Circulation ◽

10.1161/circ.116.suppl_16.ii_335-d ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Chinami Miyazaki ◽

Charles J Bruce ◽

Margaret M Redfield ◽

Raul E Espinosa ◽

David L Hayes ◽

...

Keyword(s):

Mitral Valve ◽

Cardiac Resynchronization Therapy ◽

Roc Analysis ◽

High Specificity ◽

Cardiac Resynchronization ◽

Reverse Remodeling ◽

Contraction Time ◽

Valve Closure ◽

Resynchronization Therapy ◽

Closure Time

Background: Isovolumic contraction time (ICT) and pre-ejection period (PEP) are altered by electrical conduction delay as well as impaired contractility. An abnormal PEP has been used to select patients for cardiac resynchronization therapy (CRT), however, the predictive value of PEP for reverse remodeling (RR) has not been reported. The purpose of this study is to determine the predictive value of ICT and PEP for the RR in a prospective, single center CRT registry. Methods: Prospective registry of all heart failure patients undergoing CRT with echo pre-implant and at 3 and 6 months after implant. PEP was measured from the ECG Q wave onset to the aortic valve opening from the left ventricular outflow tract pulsed-wave Doppler tracing. The timing interval from the QRS onset to mitral valve closure was measured (mitral valve closure time). ICT was calculated as PEP-mitral valve closure time. RR was defined as >15% reduction in end-systolic volume (ESV) measured by biplane Simpson’s method. Death due to cardiac cause and heart transplantation during the 6 month period were considered as a non-response in the receiver-operating characteristics (ROC)analysis. Results: Echocardiography data was available in 83 patients at 3 and 59 patients at 6 month after CRT. RR occurred in 42 patients (51%) at 3 months and in 32 (54%) patients at 6 months By ROC analysis, the area under the curve (AUC) for predicting RR was 0.74 for ICT (p<0.001) and 0.73 for PEP (p=0.001) (See table ). ICT>123 ms yielded a very high specificity of 90–93% to predict responders at 6 month after CRT either in entire population or after excluding the patients with atrial fibrillation. Conclusion: A prolonged ICT is highly specific for predicting reverse remodeling after CRT although it is found in a limited number of patients. A strategy employing a screening ICT measurement may identify patients highly likely to achieve reverse remodeling after CRT, but can not be used to exclude patients for CRT. ROC analysis

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Roentgen video densitometer study of mitral valve closure during atrial fibrillation.

Journal of Applied Physiology ◽

10.1152/jappl.1968.24.2.217 ◽

1968 ◽

Vol 24 (2) ◽

pp. 217-224 ◽

Cited By ~ 19

Author(s):

J C Williams ◽

R A Vandenberg ◽

T P O'Donovan ◽

R E Sturm ◽

E H Wood

Keyword(s):

Atrial Fibrillation ◽

Mitral Valve ◽

Valve Closure

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Motion of both mitral valve leaflets: a cineroentgenographic study in intact dogs

Journal of Applied Physiology ◽

10.1152/jappl.1975.39.3.359 ◽

1975 ◽

Vol 39 (3) ◽

pp. 359-366 ◽

Cited By ~ 19

Author(s):

A. G. Tsakiris ◽

D. A. Gordon ◽

Y. Mathieu ◽

L. Irving

Keyword(s):

Heart Rate ◽

Mitral Valve ◽

Mitral Regurgitation ◽

Mitral Annulus ◽

Valve Closure ◽

Time Motion ◽

Intraventricular Flow ◽

Radiopaque Markers ◽

Posterior Cusp ◽

Opening And Closing

Motion and position of both mitral leaflets were studied in five normal dogs 1–11 wk after radiopaque markers were sutured on the valve cusps and on the mitral annulus. Cinefluorograms and cineangiograms (100–120 frames/s) of left atrium and left ventricle were used to study cusp motion and intraventricular flow patterns, and to detect mitral regurgitation during sinus rhythm (42–184 beats/min) and during isolated atrial or ventricular contractions. Time-motion of both leaflets was similar throughout diastole with the exception of delayed posterior cusp opening. Peak opening and closing speeds, opening and closing times, and time of complete closure, measured from the Q wave of the ECG, were not significantly affected by the variations in heart rate. Diastolic leaflet closure began immediately after opening, while the ventricular cavity was small, and was caused by flow eddies behind the cusps. Isolated ventricular contractions closed the valve leaflets completely and symmetric valve closure was ensured by the different rates of leaflet edge approximation. In contrast, atrial closure was slow, partial, and of very short duration.

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Haemodynamic determinants of the mitral valve closure sound: A finite element study

Medical & Biological Engineering & Computing ◽

10.1007/bf02345218 ◽

2004 ◽

Vol 42 (6) ◽

pp. 832-846 ◽

Cited By ~ 35

Author(s):

D. R. Einstein ◽

K. S. Kunzelman ◽

P. G. Reinhall ◽

M. A. Nicosia ◽

R. P. Cochran

Keyword(s):

Finite Element ◽

Mitral Valve ◽

Valve Closure ◽

Finite Element Study ◽

Element Study

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Image-based mass-spring model of mitral valve closure for surgical planning

10.1117/12.772699 ◽

2008 ◽

Cited By ~ 19

Author(s):

Peter E. Hammer ◽

Douglas P. Perrin ◽

Pedro J. del Nido ◽

Robert D. Howe

Keyword(s):

Mitral Valve ◽

Surgical Planning ◽

Valve Closure ◽

Spring Model ◽

Mass Spring Model ◽

Mass Spring

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Improvement in right ventricular function by mitral valve closure in hypoplastic left heart syndrome

Interactive Cardiovascular and Thoracic Surgery ◽

10.1093/icvts/ivab037 ◽

2021 ◽

Author(s):

Dai Asada ◽

Yoko Kawai ◽

Yoshinobu Maeda ◽

Masaaki Yamagishi

Keyword(s):

Mitral Valve ◽

Right Ventricular ◽

Ventricular Function ◽

Hypoplastic Left Heart Syndrome ◽

Right Ventricular Function ◽

Left Ventricular ◽

Valve Closure ◽

Left Heart ◽

Hypoplastic Left Heart ◽

Left Heart Syndrome

Abstract A male neonate presented with the aortic/mitral stenotic variant of hypoplastic left heart syndrome, wherein the suprasystemic left ventricular pressure and relatively large left ventricle had shifted the intraventricular septum. Despite bilateral pulmonary artery banding, the stroke volume was difficult to maintain owing to the compressed right ventricle, causing heart failure symptoms. Percutaneous balloon aortic valvuloplasty decreased the left ventricular pressure, restoring the right ventricular function. Norwood procedure with mitral valve closure after catheter intervention reduced the left ventricular size and improved the right ventricular function. This paper refers to the potential of mitral valve closure for hypoplastic left heart syndrome.

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