Transmural gradients of cardiac myofiber shortening  in aortic valve stenosis patients using MRI tagging

Toorn, A. Van der; Barenbrug, Paul; Snoep, Gabriël; Veen, Frederik H. van der; Delhaas, Tammo; Prinzen, Frits W.; Maessen, Jos G.; Arts, Theo

doi:10.1152/ajpheart.00239.2002

Cited by 81 publications

(86 citation statements)

References 25 publications

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“…The relationship between torsion and strain can be approximated by a ratio of the peak torsion and the peak circumferential strain in the endocardial third of the myocardium, the torsion:shortening ratio. 6,38 This ratio is constant among healthy subjects of the same age and increases with healthy aging. 6,9 Both torsion and torsion:shortening ratio are measures of epicardial-endocardial interactions.…”

Section: Cardiac Taggingmentioning

confidence: 97%

Effect of Physical Activity on Age-Related Changes in Cardiac Function and Performance in Women

Jakovljevic¹,

Papakonstantinou

Blamire

et al. 2015

Circ: Cardiovascular Imaging

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Background— Higher levels of physical activity are associated with reduced cardiovascular mortality but its effect on age-related changes in cardiac structure and function is unknown. The present study defines the effect of daily physical activity on age-related changes in cardiac structure, function, metabolism, and performance in healthy women. Methods and Results— Sixty-three healthy women were grouped according to age (young, 20–30 years, n=21; middle, 40–50 years, n=22; and older, 65–81 years, n=20) and daily physical activity level (low active <7500 and high active >12 500 steps/d). Participants underwent cardiac MRI including tissue tagging and 31 P spectroscopy and exercise testing with noninvasive central hemodynamic measurements. Aging was associated with increased concentric remodeling ( P <0.01) and left ventricular torsion ( P <0.01), and a decline in diastolic function ( P <0.01), cardiac phosphocreatine:ATP ratio ( P <0.01), peak exercise cardiac power output ( P <0.01), and O 2 consumption ( P <0.01). Older high-active women demonstrated a phosphocreatine:ATP ratio and relative peak O 2 consumption similar to young low-active women, and 23% and 26% higher than older low-active women (phosphocreatine:ATP ratio, 1.9±0.2 versus 1.4±0.1; P <0.05 and O 2 consumption, 24.1±3.8 versus 17.8±2.0 mL/[kg·min]; P <0.01). In older women, physical activity had no effect on eccentricity ratio (0.9±0.2 versus 0.8±0.1 g/mL; P =0.19), E/A ratio (1.3±0.5 versus 1.4±0.5; P =0.66), torsion (7.6±1.7 versus 8.0°±2.1°; P =0.20), and peak cardiac power output (3.4±0.7 versus 3.4±0.8 W; P =0.91). Conclusions— A higher level of daily physical activity preserves cardiac metabolism and exercise capacity with aging but has limited effect on age-related changes in concentric remodeling, diastolic function, and cardiac performance.

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Section: Cardiac Taggingmentioning

confidence: 97%

Effect of Physical Activity on Age-Related Changes in Cardiac Function and Performance in Women

Jakovljevic¹,

Papakonstantinou

Blamire

et al. 2015

Circ: Cardiovascular Imaging

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“…From the two series of tagged images, maps of horizontal and vertical displacement were determined (40). To relate timing of the tagged images to phases in the cardiac cycle, for each moment in each slice, the midwall radius was determined.…”

Section: Assessment Of LV Wall Strain Using Mrtmentioning

confidence: 99%

“…magnetic resonance tagging; finite-element model; cardiac mechanics; myofiber angle DEFORMATION OF THE CARDIAC WALL can be assessed noninvasively using ultrasound strain rate imaging (11) or magnetic resonance tagging (MRT) (4). The deformation patterns acquired may deviate from normal in the case of cardiac pathology, e.g., aortic stenosis, ischemia, or conduction disorders (39,40,43). The analysis of abnormal deformation patterns toward the underlying pathology is not straightforward: the relation between the change in the deformation pattern and the pathology is complex, and the criteria for normal and abnormal strain patterns have not yet been defined.…”

mentioning

confidence: 99%

Determinants of left ventricular shear strain

Bovendeerd¹,

Kroon²,

Delhaas³

2009

American Journal of Physiology-Heart and Circulatory Physiology

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matical models of cardiac mechanics can potentially be used to relate abnormal cardiac deformation, as measured noninvasively by ultrasound strain rate imaging or magnetic resonance tagging (MRT), to the underlying pathology. However, with current models, the correct prediction of wall shear strain has proven to be difficult, even for the normal healthy heart. Discrepancies between simulated and measured strains have been attributed to 1) inadequate modeling of passive tissue behavior, 2) neglecting active stress development perpendicular to the myofiber direction, or 3) neglecting crossover of myofibers in between subendocardial and subepicardial layers. In this study, we used a finite-element model of left ventricular (LV) mechanics to investigate the sensitivity of midwall circumferential-radial shear strain (Ecr) to settings of parameters determining passive shear stiffness, cross-fiber active stress development, and transmural crossover of myofibers. Simulated time courses of midwall LV Ecr were compared with time courses obtained in three healthy volunteers using MRT. Ecr as measured in the volunteers during the cardiac cycle was characterized by an amplitude of ϳ0.1. In the simulations, a realistic amplitude of the Ecr signal could be obtained by tuning either of the three model components mentioned above. However, a realistic time course of Ecr, with virtually no change of Ecr during isovolumic contraction and a correct base-to-apex gradient of Ecr during ejection, could only be obtained by including transmural crossover of myofibers. Thus, accounting for this crossover seems to be essential for a realistic model of LV wall mechanics. magnetic resonance tagging; finite-element model; cardiac mechanics; myofiber angle DEFORMATION OF THE CARDIAC WALL can be assessed noninvasively using ultrasound strain rate imaging (11) or magnetic resonance tagging (MRT) (4). The deformation patterns acquired may deviate from normal in the case of cardiac pathology, e.g., aortic stenosis, ischemia, or conduction disorders (39,40,43). The analysis of abnormal deformation patterns toward the underlying pathology is not straightforward: the relation between the change in the deformation pattern and the pathology is complex, and the criteria for normal and abnormal strain patterns have not yet been defined. A mathematical model capable of predicting the forward relation between pathology and deformation could, if used in an inverse analysis, be a useful clinical tool, not only in diagnosis but also in intervention selection and planning, by simulating candidate interventions beforehand.Several models describing the deformation of cardiac walls have been proposed (5,6,14,19,20,28,35,41,42,45), but none of these models have already been used as a diagnostic tool. As a first step toward this application, one would require the models to be able to correctly predict deformation in the wall of the healthy heart. Most models are able to correctly predict circumferential, longitudinal, and radial strain (5,14,28,41,42,45). However, ...

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“…Furthermore, the torsion-to-shortening ratio (TSR) parameter was calculated for both rats and humans. TSR indicates the transmural distribution of contractile myofibers and their function (2,5,29). For example, it has been found that TSR is different for aortic stenosis patients than for normal subjects due to the change in the transmural distribution of the myocardial fibers resulting from a remodeling process (29).…”

mentioning

confidence: 99%

Layer-specific strain analysis by speckle tracking echocardiography reveals differences in left ventricular function between rats and humans

Bachner-Hinenzon¹,

Ertracht

Leitman

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

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-specific strain analysis by speckle tracking echocardiography reveals differences in left ventricular function between rats and humans. Am J Physiol Heart Circ Physiol 299: H664 -H672, 2010. First published July 2, 2010; doi:10.1152/ajpheart.00017.2010.-The rat heart is commonly used as an experimental model of the human heart in both health and disease states, assuming that heart function of rats and humans is alike. When studying a rat model, echocardiography is usually performed on sedated rats, whereas standard echocardiography on adult humans does not require any sedation. Since echocardiography results of sedated rats are usually inferred to alert humans, in the present study, we tested the hypothesis that differences in left ventricular (LV) function may be present between rats sedated by a low dose of ketamine-xylazine and alert humans. Echocardiography was applied to 110 healthy sedated rats and 120 healthy alert humans. Strain parameters were calculated from the scans using a layer-specific speckle tracking echocardiography program. The results showed that layer longitudinal strain is equal in rats and humans, whereas segmental strain is heterogeneous (P Ͻ 0.05) in a different way in rats and humans (P Ͻ 0.05). Furthermore, layer circumferential strain is larger in humans (P Ͻ 0.001), and the segmental results showed different segmental heterogeneity in rats and humans (P Ͻ 0.05). Radial strain was found to be homogeneous at the apex and papillary muscle levels in humans and heterogeneous in rats (P Ͻ 0.001). Additionally, whereas LV twist was equal in rats and humans, in rats the rotation was larger at the apex (P Ͻ 0.01) and smaller at the base (P Ͻ 0.001). The torsion-to-shortening ratio parameter, which indicates the transmural distribution of contractile myofibers, was found to be equal in rats and humans. Thus, when evaluating LV function of sedated rats under ketamine-xylazine, it is recommended to measure the global longitudinal strain, LV twist, and torsion-to-shortening ratio, since no scaling is required when converting these parameters and inferring them to humans. speckle training; strain imaging; contractility RATS PLAY AN IMPORTANT ROLE in modeling human left ventricular (LV) function, and thus a variety of pathologies, such as myocardial infarction (20, 30) and cardiomyopathy (17, 19), are commonly induced in rats, so that their effect on LV function can be analyzed under controlled conditions. Consequently, the pertinent questions are 1) does the similarity in LV structure between rats and humans (4, 10) result in similar LV function? and 2) is the rat LV an appropriate model for studying human LV function?To evaluate the properties that quantify LV function, a method known as speckle tracking echocardiography (STE) has been recently developed (1, 3 , 9, 11, 13, 14, 18, 20, 23). The STE method uses standard two-dimensional (2-D) echocardiography cines and tracks the speckles in the ultrasound B-mode image sequence of the myocardium, and, subsequently, the parameters of local function ...

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Transmural gradients of cardiac myofiber shortening in aortic valve stenosis patients using MRI tagging

Cited by 81 publications

References 25 publications

Effect of Physical Activity on Age-Related Changes in Cardiac Function and Performance in Women

Effect of Physical Activity on Age-Related Changes in Cardiac Function and Performance in Women

Determinants of left ventricular shear strain

Layer-specific strain analysis by speckle tracking echocardiography reveals differences in left ventricular function between rats and humans

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