Simulation and Imaging of the Cardiac System: State of the HeartS. Sideman, Rafael Beyar The ultrasound velocity tomography allows measurement of cardiac geometries for various phases in the cardiac cycle. The present tomograph makes reconstruc tions at intervals of 20 ms. Because of a lack of clear (intramural) landmarks (except the roots of the papillairy muscle), it is difficult to pinpoint spatial trajectories of particular points in the heart. Therefore, a second method was developed of injecting radiopaque markers in the heart and following their motion patterns during the cardiac cycle with help of a biplane X-ray equipment. The data obtained with both methods can be implemented in our finite element model of the heart to compute intramural stresses and strains. The results obtained sofar with the extended Darcy equation to account for the interaction of blood rheology and tissue mechanics look promising. Further testing with more sophisticated subjects than mentioned in Figure 9 is required before it will be implemented in our finite element model of the heart. We conclude that analysis of regional cardiac function, including regional myocardial blood flow, requires still a major research effort but the results obtained sofar justify, to our opinion, a continuation in this direction. Acknowledgement The authors acknowledge Dr. C. Borst and coworkers for doing the animal experiments and prof. Van Campen and dr. Grootenboer for their participation is some aspects of this work. |
Contents
The role of mathematical models in an assessment of myocardial | 35 |
Cardiac Mechanics | 58 |
Advantages and limitations | 76 |
Copyright | |
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Other editions - View all
Simulation and Imaging of the Cardiac System: State of the Heart S. Sideman,Rafael Beyar Limited preview - 2012 |
Simulation and Imaging of the Cardiac System: State of the Heart S. Sideman,Rafael Beyar No preview available - 2011 |
Common terms and phrases
activation adenosine afterload aortic aspartate Beyar Biomedical Engineering calculated cardiac cycle cardiac muscle cardiac output cardiovascular cell Circ Res circulation citric acid cycle clinical contractile contraction coronary artery coronary blood flow coronary circulation coronary flow cross sections curve developed diastolic dipyridamole distribution dynamic effect ejection elastic electrical electrocardiogram end diastolic end systolic endocardial energy epicardial potentials epicardium equation experimental Feigl fiber finite element analysis flux function geometry Geselowitz glutamate heart rate Heintzen PH increase infarction inverse isoptomers layers left ventricle left ventricular linear measured mechanical metabolic Mirsky mmHg myocardium normal obtained oxygen oxygen consumption Pao YC parameters perfusion Physiol physiological pressure-volume relation problem properties quantitative reconstruction regional relationship resistance Ritman Sagawa sarcomere shown in Figure Sideman simulation spatial stiffness stroke volume studies systolic techniques tissue transmural ultrasound values valve vascular vasodilation velocity venous vessels vivo wall stress