caa a22 4500 469122943 CHVBK 20180323133144.0 cr unu---uuuuu 170328e19920301xx s 000 0 eng 10.1007/BF02368517 doi (NATIONALLICENCE)springer-10.1007/BF02368517 A conical model to describe the nonuniformity of the left ventricular twisting motion [Elektronische Daten] [H. Azhari, M. Buchalter, S. Sideman, E. Shapiro, R. Beyar] The systolic contraction and fiber shortening in the left ventricle (LV) produces torsional moments in the myocardium, resulting in a gradient of angular displacements about the long axis. This is manifested as a counterclockwise rotation of the apex relative to the base, when viewed from the apex. Recent studies with magnetic resonance imaging (MRI), using noninvasive magnetic tags, have revealed three important properties of the LV twist: (a) The angle of twist (i.e., the angular rotation of a slice relative to the basal slice) is consistently higher at the endocardium as compared to the epicardium; (b) The twist increases towards the apex; and (c) Straight MRI-tagged radial lines at end-diastole (ED) are slightly curved at end-systole (ES), implying a nonlinear transmural variation of the twist. The present study suggests that the geometry of the LV at ES can be represented by a thick-walled hollow cone, and that the transmural twist patterns from ED to ES can be described using the continuum mechanics approach and a small strain analysis of an isotropic cone subjected to external torque. The predicted results are compared with the noninvasive MRI measurements of transmural twist in eight human volunteers. Given the epicardial angles of twist of each slice, the predicted endocardial angles of twist are in good correlation with the experimental findings (r=0.86, slope=1.09, SEE=4.1°). In addition, the model reliably describes the changes in the twist magnitude from apex to base (no significant difference from experimental values,P=0.2), and predicts the curvilinear pattern at ES of the originally straight ED radial lines. Thus, the conical model with uniform properties of the LV, reliably predicts the nonuniformity of the twist patterns, implying that the LV twist is strongly affected by LV geometry. Pergamon Press Ltd., 1992 Left ventricle nationallicence Model nationallicence Cone nationallicence Twist nationallicence Nonuniformity nationallicence Azhari H. The Heart System Research Center Julius Silver Institute Department of Biomedical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel aut Buchalter M. Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD aut Sideman S. The Heart System Research Center Julius Silver Institute Department of Biomedical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel aut Shapiro E. Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD aut Beyar R. The Heart System Research Center Julius Silver Institute Department of Biomedical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel aut Annals of Biomedical Engineering Kluwer Academic Publishers 20/2(1992-03-01), 149-165 0090-6964 20:2<149 1992 20 10439 https://doi.org/10.1007/BF02368517 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02368517 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Azhari H. The Heart System Research Center Julius Silver Institute Department of Biomedical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel aut NATIONALLICENCE 700 1- Buchalter M. Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD aut NATIONALLICENCE 700 1- Sideman S. The Heart System Research Center Julius Silver Institute Department of Biomedical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel aut NATIONALLICENCE 700 1- Shapiro E. Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD aut NATIONALLICENCE 700 1- Beyar R. The Heart System Research Center Julius Silver Institute Department of Biomedical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel aut NATIONALLICENCE 773 0- Annals of Biomedical Engineering Kluwer Academic Publishers 20/2(1992-03-01), 149-165 0090-6964 20:2<149 1992 20 10439 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer