Limited knowledge exists regarding the forces which act on devices implanted to the heart's mitral valve. Developing a transducer to measure the peak force magnitudes, time rates of change, and relationship with left ventricular pressure will aid in device development. A novel force transducer was developed and implanted in the mitral valve annulus of an ovine subject. In the post-cardioplegic heart, septal-lateral and transverse forces were continuously measured for cardiac cycles reaching a peak left ventricular pressure of 90 mmHg. Each force was seen to increase from ventricular diastole and found to peak at mid-systole. The mean change in septal-lateral and transverse forces throughout the cardiac cycle was 4.4±0.2 N and 1.9±0.1 N respectively. During isovolumetric contraction, the septal-lateral and transverse forces were found to increase at peak rate of 143±8 N/s and 34±9 N/s, respectively. Combined, this study provides the first quantitative assessment of septal-lateral and transverse forces within the contractile mitral annulus. The developed transducer was successful in measuring these forces whose methods may be extended to future studies. Upon additional investigation, these data may contribute to the safer development and evaluation of devices aimed to repair or replace mitral valve function.
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http://dx.doi.org/10.1016/j.jbiomech.2012.03.009 | DOI Listing |
J Artif Organs
June 2019
Department of Cardiovascular and Thoracic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo, 060-8638, Japan.
Ideally, an annuloplasty ring's shape should be changed intraoperatively if mitral valve repair is unsuccessful because of a short coaptation length or systolic anterior motion. Several post-implantation adjustable rings have been developed, but they are not freely deformable and are unsuitable for asymmetric repair of the valvular annulus. We developed a novel thermally deformable mitral annuloplasty ring to address these problems and assessed the ring's mechanical properties and its effect on the mitral valve anatomy.
View Article and Find Full Text PDFJ Thorac Cardiovasc Surg
August 2013
The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga, USA.
Objective: Forces acting on mitral annular devices in the setting of ischemic mitral regurgitation are currently unknown. The aim of this study was to quantify the cyclic forces that result from mitral annular contraction in a chronic ischemic mitral regurgitation ovine model and compare them with forces measured previously in healthy animals.
Methods: A novel force transducer was implanted in the mitral annulus of 6 ovine subjects 8 weeks after an inferior left ventricle infarction that produced progressive, severe chronic ischemic mitral regurgitation.
Ann Thorac Surg
July 2012
The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA.
Background: Limited knowledge exists regarding the forces that act on devices implanted in the mitral annulus. Determining the peak magnitudes, directions, rates, variation throughout the cardiac cycle, and change with left ventricular pressure (LVP) will aid in device development and evaluation.
Methods: Novel transducers with the ability to measure forces in the septal-lateral and transverse directions were implanted in six healthy ovine subjects.
J Biomech
May 2012
The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Dr., Atlanta, GA 30332, USA.
Limited knowledge exists regarding the forces which act on devices implanted to the heart's mitral valve. Developing a transducer to measure the peak force magnitudes, time rates of change, and relationship with left ventricular pressure will aid in device development. A novel force transducer was developed and implanted in the mitral valve annulus of an ovine subject.
View Article and Find Full Text PDFEur J Cardiothorac Surg
June 2010
Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
Objective: This study evaluates the ability of a novel epicardial annuloplasty device Mitral Touch (MAQUET Cardiovascular LLC, San Jose, CA, USA) to reduce functional mitral regurgitation (MR) in a rapid ventricular pacing-induced dilated cardiomyopathy model in dogs.
Methods: A median sternotomy was performed in 13 dogs after MR induction by rapid ventricular pacing (230 beats/min for an average of 35.6 + or - 12.
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