Mechanics of ventricular torsion

Taber, Larry A.; Yang, Ming; Podszus, W.William

doi:10.1016/0021-9290(95)00129-8

Cited by 204 publications

(172 citation statements)

References 25 publications

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“…During ejection, myofibers shorten across the entire transmural wall of the LV. However, the direction of rotation is governed by the subepicardial fibers owing to their longer arm of movement (50) and their intrinsic contractile properties (51). Shortening of subepicardial fibers results in counterclockwise rotation of the LV apex and clockwise rotation of the LV base.…”

Section: Sequence Of the LV Rotationmentioning

confidence: 99%

Left Ventricular Form and Function Revisited: Applied Translational Science to Cardiovascular Ultrasound Imaging

Sengupta

Krishnamoorthy

Kořínek

et al. 2007

Journal of the American Society of Echocardiography

287

196

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Tissue Doppler imaging (TDI) and TDI-derived strain imaging are robust physiologic tools used for the noninvasive assessment of regional myocardial function. Due to high temporal and spatial resolution, regional function can be assessed for each phase of the cardiac cycle and within the transmural layers of the myocardial wall. Newer techniques that measure myocardial motion by speckle tracking in grayscale images have overcome the angle dependence of TDI strain, allowing for measurement of 2-dimensional strain and cardiac rotation. TDI, TDI strain, and speckle tracking may provide unique information that deciphers the deformation sequence of complexly oriented myofibers in the left ventricular wall. The data are, however, limited. This review examines the structure and function of the left ventricle relative to the potential clinical application of TDI and speckle tracking in assessing the global mechanical sequence of the left ventricle in vivo.The spiral arrangement of muscle fibers in the heart is reminiscent of spiral and vortex patterns in nature, ranging from small organelles and whirlpools to hurricanes and rotational patterns of the galaxies (1-5). Vortex patterns link two fundamental forms of motion that work in close balance: an inner, rapidly descending swirl and an outer, less rapid, ascending rotation (4) ( Fig. 1 A-C). These counterdirectional movements of a vortex produce suction and expulsion forces that have been exploited for designing energy efficient propellers and turbines (6). Likewise, experimental and mathematical modeling of the clockwise and counterclockwise spiral loops of myofibers in the left ventricle (LV) has shown that counterdirectional geometry provides an efficient distribution of regional stresses and strains (7). Conversely, altered ventricular geometry resulting from cardiac remodeling, regional myocardial dysfunction, or asynchronous conduction distort the efficiency of the loading and expulsion dynamics (8,9). In this review, we associate the LV myofiber architecture to the spatiotemporal sequence of regional deformations occurring during normal cardiac contraction and relaxation. We further elucidate experimental observations, which explore the application of tissue Doppler imaging (TDI) and 2-dimensional ultrasound speckle tracking for delineation of the synchronous mechanical shortening and lengthening sequences of the human LV.Address reprint requests to Marek Belohlavek, Division of Cardiovascular Diseases, Mayo Clinic, 13400 East Shea Boulevard Scottsdale, AZ 85259, E-mail address for author named in reprint line: Belohlavek.marek@mayo.edu Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect th...

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Section: Sequence Of the LV Rotationmentioning

confidence: 99%

Left Ventricular Form and Function Revisited: Applied Translational Science to Cardiovascular Ultrasound Imaging

Sengupta

Krishnamoorthy

Kořínek

et al. 2007

Journal of the American Society of Echocardiography

287

196

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“…Two-dimensional speckle tracking echocardiography (2D STE) is a valuable tool to evaluate global and regional LV function and appears to be more precise and distinctive than traditional echocardiography for detecting subtle myocardial abnormalities [4][5][6]. Apical and basal LV rotation have been described as an important part of LV twist, which plays a key role in maintaining both systolic and diastolic function [5][6][7][8]. LV untwisting parameters have been used to quantify LV diastolic function by 2D STE [5,8].…”

Section: Introductionmentioning

confidence: 99%

Left ventricular function after takotsubo is not fully recovered in long-term follow-up: A speckle tracking echocardiography study

et al. 2017

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“…It has been long known that left ventricular (LV) myocardial microstructure or fiber structure plays a critical role in determining mechanical properties, such as ventricular torsion, strain, and stress (3,4). Owing to the recent advances in cardiac MR and ultrasound imaging, there is an increasing interest in investigating LV by directly associating the LV myocardial fiber geometry to the complex spatial-temporal sequence of electrical activation and mechanical contraction/relaxation in beating hearts (1,2,5).…”

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confidence: 99%

MR diffusion tensor imaging study of postinfarct myocardium structural remodeling in a porcine model

Nicholls

et al. 2007

Magnetic Resonance in Med

117

110

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This study aimed to investigate postinfarct left ventricular (LV) fiber structural alterations by ex vivo diffusion tensor imaging (DTI) in a porcine heart model. In vivo cardiac MR imaging was first performed to measure ventricular function in six adult pigs with septal infarction near apex induced by the LAD ligation 13 weeks earlier. Hearts were then excised from the infarct pigs (n ‫؍‬ 6) and six intact controls (n ‫؍‬ 6) and fixed in formalin. High-resolution DTI was employed to examine changes in fractional anisotropy (FA), apparent diffusion coefficient (ADC), and transmural helix angle distribution in the infarct, adjacent and remote regions as compared to the sham regions in the controls. FA values were found to decrease in the infarct and differ between the adjacent and remote regions. ADC increase in the infarct region was substantial, while changes in the adjacent and remote regions were insignificant. Structurally, the doublehelix myocardial structure shifted toward more left-handed around the infarcted myocardium. Accordingly, the histological analysis revealed clear fiber structural degradation in the adjacent region. These findings confirmed the subtle alterations in the myocardial fiber quality and structure not only in the in- Key words: myocardium infarction; borderzone; diffusion tensor imaging; fiber architecture Both structural and functional assessments are important in our understanding of myocardial contraction and relaxation in normal and pathologic states (1,2). It has been long known that left ventricular (LV) myocardial microstructure or fiber structure plays a critical role in determining mechanical properties, such as ventricular torsion, strain, and stress (3,4). Owing to the recent advances in cardiac MR and ultrasound imaging, there is an increasing interest in investigating LV by directly associating the LV myocardial fiber geometry to the complex spatial-temporal sequence of electrical activation and mechanical contraction/relaxation in beating hearts (1,2,5). LV is known to electrically activate first at the exits of Purkinje system, close to apical endocardium. The electrical activation then propagates from apex to base via depolarization and repolarization in both septum and free wall (1,6). This is accompanied by successive mechanical shortenings and intracavitary blood flow along the parallel apex-to-base direction, although highly transient and localized myocardial deformations exist.In infarcted myocardium, remodeling involves both structural and functional changes. Such changes have been found to occur in both infarcted myocardium and adjacent and remote myocardium (7-11). The effects of myocardial infarction (MI) on LV function have been investigated in numerous studies. In recent years, cardiac MR (CMR) imaging has become the accepted reference standard to assess LV function since CMR methods are both accurate and highly reproducible (12). These CMR techniques can be used to detect, localize, and quantify both MI and LV functions. Patten et al. (13) found that hearts...

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Mechanics of ventricular torsion

Cited by 204 publications

References 25 publications

Left Ventricular Form and Function Revisited: Applied Translational Science to Cardiovascular Ultrasound Imaging

Left Ventricular Form and Function Revisited: Applied Translational Science to Cardiovascular Ultrasound Imaging

Left ventricular function after takotsubo is not fully recovered in long-term follow-up: A speckle tracking echocardiography study

MR diffusion tensor imaging study of postinfarct myocardium structural remodeling in a porcine model

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