Key References
MRI assessment of LV relaxation by untwisting rate: a new isovolumic phase measure of tau
S.J. Dong, P.S. Hees, C.O. Siu, H.L. Weiss and E.P. Shapiro
Comment:
The development of an accurate method for assessing left ventricular diastolic function that does not require pressure measurement and is “relatively” load independent is an ongoing challenge. Most of actual measures provide little information about the isovolumic relaxation period when the majority of relaxation occurs. One approach for noninvasively assessing isovolumic relaxation is through the measurement of the degree of LV twisting (torsion) that occurs during systole and the rate of untwisting during diastole.
Reference: Am J Physiol Heart Circ Physiol. 2001 Nov;281(5):H2002-9
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Regional left ventricular electric and mechanical activation and relaxation
O.A. Smiseth and E.W. Remme
Comment:
Torsion occurs in the normal heart because the orientation of the myocardial fibers varies across the wall. The subendocardial fibers have an approximately longitudinal orientation with and angle of 80° relative to the circumferential plane. This angle decreases toward the mid-wall, where the fibers are circumferentially oriented (0°), and decreases further to an oblique orientation of approximately −60° at the subepicardium
Reference: J Am Coll Cardiol. 2006 Jan 3;47(1):173-4.
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Enhanced ventricular untwisting during exercise: a mechanistic manifestation of elastic recoil described by Doppler tissue imaging
Y. Notomi, M.G. Martin-Miklovic and S.J. Oryszak et al
Comment:
Diastolic recoil or “untwisting” is related to the systolic compression of elastic proteins and elastic recoil contributes to the development of the intracavitary gradient that precedes mitral valve opening (diastolic suction).
Reference: Circulation. 2006 May 30;113(21):2524-33.
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Restoring forces assessed with left atrial pressure clamps
S.P. Bell, J. Fabian and A. Higashiyama et al
Reference: Am J Physiol. 1996 Mar;270(3 Pt 2):H1015-20.
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Left atrial pressure-clamp servomechanism demonstrates LV suction in canine hearts with normal mitral valves
N.B. Ingels Jr., G.T. Daughters 2nd and S.D. Nikolic et al.
Reference: Am J Physiol 267 (1994), pp. H354–H362.
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Measurement of ventricular torsion by two-dimensional ultrasound speckle tracking imaging
Y. Notomi, P. Lysyansky and R.M. Setser et al.
Reference: J Am Coll Cardiol 45 (2005), pp. 2034–2041.
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Assessment of left ventricular torsional deformation by Doppler tissue imaging: validation study with tagged magnetic resonance imaging
Y. Notomi, R.M. Setser and T. Shiota et al.
Comment:
Two echocardiographic methods have been proposed to measure torsion: Doppler Tissue Imaging (DTI) and Speckle Tracking (STE), both of which have been shown to correlate with magnetic resonance imaging (MRI) when used in small groups of patients.
Reference: Circulation 111 (2005), pp. 1141–1147
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Maturational and adaptive modulation of left ventricular torsional biomechanics: Doppler tissue imaging observation from infancy to adulthood
Y. Notomi, G. Srinath and T. Shiota et al.
Comment:
Because cardiac cellular structure and function change from infancy to adulthood, it is reasonable to ask whether torsional biomechanics also change. In a study of 45 normal subjects ranging in age from 9 days to 49 years, the authors observed by using DTI that LV torsion increased with age, owing primarily to the augmentation of basal clockwise rotation during childhood and apical counterclockwise rotation during adulthood. Although peak LV torsion and untwisting velocity showed age-related increases, when normalized by LV length, greater values were observed in infants and middle-aged patients. The proportion of untwisting during isovolumic relaxation was lowest during infancy and increased progressively being highest in middle age; however, peak normalized untwisting velocity (peak untwisting velocity normalized by peak LV torsion) showed a decrease in adulthood.
Reference: Circulation 113 (2006), pp. 2534–2541
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Age-related changes in left ventricular twist assessed by two-dimensional speckle-tracking imaging
M. Takeuchi, H. Nakai and M. Kokumai et al.
Comment:
This is a study of 118 adults, using STE, that similarly examined the effects of aging on torsion and untwisting. Patients were divided in 3 groups (young, <40 year [n = 57]; middle-aged, 40 to 60 years [n = 41]; and older subjects, >60 years [n = 15]). Torsion increased with age. Untwisting rates were significantly lower in middle age and older groups than in the young group. No gender differences were noted in peak twist or untwisting velocities.
Reference: J Am Soc Echocardiogr 19 (2006), pp. 1077–1084.
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Myocardial adaptation to short-term high-intensity exercise in highly trained athletes
T.G. Neilan, T.T. Ton-Nu and D.S. Jassal et al.
Comment:
This study showed that torsion increased from baseline to the end of a 2,000-m world indoor rowing championship. The smaller increase in torsion after much more strenuous efforts may reflect the difference in measurements made during versus after exercise.
Reference: J Am Soc Echocardiogr 19 (2006), pp. 1280–1285.
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New noninvasive method for assessment of left ventricular rotation: speckle tracking echocardiography
T. Helle-Valle, J. Crosby and T. Edvardsen et al.
Comment:
Validation study comparing STE to sonomicrometer measurements, authors found an excellent correlation between the 2 methods for apical rotation however, for basal rotation, the correlation decreased slightly. Conversely, the correlation of the time to peak rotation was better at the base than at the apex. They showed corresponding increases in rotation during dobutamine infusion and decreases in apical rotation after left anterior descending artery (LAD) ligation without affecting basal rotation. STE is dependent on the quality of the 2-dimensional images, and subendocardial speckles have been noted to be more easily identified than subepicardial echoes. Preferential subendocardial sampling may increase torsion values because subendocardial torsion is nearly twice that of the subepicardium. STE at the base may be complicated by through plane translation that may explain the poorer correlations for basal rotation when compared with reference standards. Peak rotation of the apex and base do not necessarily occur at the same time, with the result that instantaneous peak torsion may be smaller than the difference between peak apical and peak basal rotation.
Reference Circulation 112 (2005), pp. 3149–3156
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Three-dimensional systolic strain patterns in the normal human left ventricle: characterization with tagged MR imaging
C.C. Moore, C.H. Lugo-Olivieri and E.R. McVeigh et al.
Comment:
For comparable ages, there is wide variability in the reported values for resting systolic torsion. Torsion varies regionally around the ventricle, increases from epicardium to endocardium, and is nonlinear from apex to base. Because the greatest amount of twist occurs at the apex, the position of apical sampling would appear to be critical and is difficult to precisely standardize.
Reference: Radiology 214 (2000), pp. 453–466
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Noninvasive quantification of left ventricular rotational deformation in normal humans using magnetic resonance imaging myocardial tagging
M.B. Buchalter, J.L. Weiss and W.J. Rogers et al.
Comment:
Preferential subendocardial sampling may increase torsion values because subendocardial torsion is nearly twice that of the subepicardium. STE at the base may be complicated by through plane translation that may explain the poorer correlations for basal rotation when compared with reference standards. Peak rotation of the apex and base do not necessarily occur at the same time, with the result that instantaneous peak torsion may be smaller than the difference between peak apical and peak basal rotation.
Reference Circulation 81 (1990), pp. 1236–1244
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Left ventricular torsion is equal in mice and humans
R.E. Henson, S.K. Song and J.S. Pastorek et al.
Comment:
Although absolute torsion in infants is less than in adults, LVtor normalized for ventricular length is greater in infants than in older children, adolescents, and adults, which is consistent with the higher contractility noted in infants. Likewise, the mouse heart has an apex to base angular deformity that is a fraction of the human value; however, when normalized for LV length, the 2 species become equal.
Reference: Am J Physiol Heart Circ Physiol 278 (2000), pp. H1117–H1123.
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Cardiac rotation and relaxation in patients with aortic valve stenosis
E. Nagel, M. Stuber and B. Burkhard et al.
Comment:
Torsion varies with changes in preload, afterload, and contractility. In the experimental model, torsion was shown to increase with increasing end-diastolic volume at constant end-systolic volumes and to decrease with increasing end-systolic volumes at constant end-diastolic volumes.
Reference: Eur Heart J 21 (2000), pp. 582–589.
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Alterations in the local myocardial motion pattern in patients suffering from pressure overload due to aortic stenosis
M. Stuber, M.B. Scheidegger and S.E. Fischer et al.
Comment:
In volume-loading studies, both end-diastolic and end-systolic volumes tend to increases in parallel and the relative forces therefore tend to balance each other. Inotropic stimulation increases torsion, as does increasing afterload.
Reference: Circulation 100 (1999), pp. 361–368
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Three-dimensional left ventricular deformation in hypertrophic cardiomyopathy
A.A. Young, C.M. Kramer and V.A. Ferrari et al.
Comment:
Left ventricular hypertrophy has been shown to increase torsion, presumably as the result of an increase in the radius of the subepicardial fibers relative to the subendocardial fibers, although subendocardial ischemia also may contribute.
Reference: Circulation 90 (1994), pp. 854–867
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