Defining Left Ventricular Apex-to-Base Twist Mechanics Computed From High-Resolution 3D Echocardiography

Ashraf, Muhammad; Myronenko, Andriy; Nguyen, Thuan; Inage, Akio; Smith, Wayne; Lowe, Robert I.; Thiele, Karl; Kroeker, Carol A. Gibbons; Tyberg, John V.; Smallhorn, Jeffrey F.; Sahn, David J.; Song, Xubo

doi:10.1016/j.jcmg.2009.09.027

Cited by 43 publications

(44 citation statements)

References 19 publications

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“…In the reduced-function model the torsion angle change was reduced to 5.8 deg. These e.stimates fit well with values in porcine experimental models reported in the literature [22].…”

Section: Resultssupporting

confidence: 86%

Cardiac Assist With a Twist: Apical Torsion as a Means to Improve Failing Heart Function

Trumble

McGregor

Kerckhoffs

et al. 2011

Journal of Biomechanical Engineering

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Changes in muscle fiber orientation across the wall of the left ventricle (LV) cause the apex of the heart to turn 10-15 deg in opposition to its base during systole and are believed to increase stroke volume and lower wall stress in healthy hearts. Studies show that cardiac torsion is sensitive to various disease states, which suggests that it may be an important aspect of cardiac function. Modern imaging techniques have sparked renewed interest in cardiac torsion dynamics, but no work has been done to determine whether mechanically augmented apical torsion can be used to restore function to failing hearts. In this report, we discuss the potential advantages of this approach and present evidence that turning the cardiac apex by mechanical means can displace a clinically significant volume of blood from failing hearts. Computational models of normal and reduced-function LVs were created to predict the effects of applied apical torsion on ventricular stroke work and wall stress. These same conditions were reproduced in anesthetized pigs with drug-induced heart failure using a custom apical torsion device programmed to rotate over various angles during cardiac systole. Simulations of applied 90 deg torsion in a prolate spheroidal computational model of a reduced-function pig heart produced significant increases in stroke work (25%) and stroke volume with reduced fiber stress in the epicardial region. These calculations were in substantial agreement with corresponding in vivo measurements. Specifically, the computer model predicted torsion-induced stroke volume increases from 13.1 to 14.4 mL (9.9%) while actual stroke volume in a pig heart of similar size and degree of dysfunction increased from 11.1 to 13.0 mL (17.1%). Likewise, peak LV pressures in the computer model rose from 85 to 95 mm Hg (11.7%) with torsion while maximum ventricular pressures in vivo increased in similar proportion, from 55 to 61 mm Hg (10.9%). These data suggest that: (a) the computer model of apical torsion developed for this work is a fair and accurate predictor of experimental outcomes, and (b) supra-physiologic apical torsion may be a viable means to boost cardiac output while avoiding blood contact that occurs with other assist methods.

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“…In the reduced-function model the torsion angle change was reduced to 5.8 deg. These e.stimates fit well with values in porcine experimental models reported in the literature [22].…”

Section: Resultssupporting

confidence: 86%

Cardiac Assist With a Twist: Apical Torsion as a Means to Improve Failing Heart Function

Trumble

McGregor

Kerckhoffs

et al. 2011

Journal of Biomechanical Engineering

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show abstract

“…For animal experiments, sonomicrometry is also taken as gold standard. It has already been used for assessing the accuracy of motion-derived measures such as twist [22] or surface area changes [23]. Segmental strain values obtained by tracking and sonomicrometry were compared by Seo et al [24] and Heyde et al [25].…”

Section: A Validation Of 3d Us Strain Algorithmsmentioning

confidence: 99%

3D Strain Assessment in Ultrasound (Straus): A Synthetic Comparison of Five Tracking Methodologies

Craene

Marchesseau

Heyde

et al. 2013

IEEE Trans. Med. Imaging

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“…Both longitudinal strain and circumferential strain parameters derived from 3DSTE have been shown to be different and more accurate than strain parameters derived from 2D speckle tracking (2DSTE) 18. 3DSTE has also been shown to be a superior method of quantifying LV twist and torsion compared with 2DSTE 19. 2DSTE can display inferior tracking because of speckles moving out of the imaging plane in the z ‐axis direction 18, 20.…”

Section: Discussionmentioning

confidence: 99%

Global longitudinal strain corrected by RR interval is a superior predictor of all‐cause mortality in patients with systolic heart failure and atrial fibrillation

et al. 2017

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AimsQuantification of systolic function in patients with atrial fibrillation (AF) is challenging. A novel approach, based on RR interval correction, to counteract the varying heart cycle lengths in AF has recently been proposed. Whether this method is superior in patients with systolic heart failure (HFrEF) with AF remains unknown. This study investigates the prognostic value of RR interval‐corrected peak global longitudinal strain {GLSc = GLS/[RR^(1/2)]} in relation to all‐cause mortality in HFrEF patients displaying AF during echocardiographic examination.Methods and resultsEchocardiograms from 151 patients with HFrEF and AF during examination were analysed offline. Peak global longitudinal strain (GLS) was averaged from 18 myocardial segments obtained from three apical views. GLS was indexed with the square root of the RR interval {GLSc = GLS/[RR^(1/2)]}. Endpoint was all‐cause mortality. During a median follow‐up of 2.7 years, 40 patients (26.5%) died. Neither uncorrected GLS (P = 0.056) nor left ventricular ejection fraction (P = 0.053) was significantly associated with all‐cause mortality. After RR^(1/2) indexation, GLSc became a significant predictor of all‐cause mortality (hazard ratio 1.16, 95% confidence interval 1.02–1.22, P = 0.014, per %/s^(1/2) decrease). GLSc remained an independent predictor of mortality after multivariable adjustment (age, sex, mean heart rate, mean arterial blood pressure, left atrial volume index, and E/e′) (hazard ratio 1.17, 95% confidence interval 1.05–1.31, P = 0.005 per %/s^(1/2) decrease).ConclusionsDecreasing {GLSc = GLS/[RR^(1/2)]}, but not uncorrected GLS nor left ventricular ejection fraction, was significantly associated with increased risk of all‐cause mortality in HFrEF patients with AF and remained an independent predictor after multivariable adjustment.

show abstract

Defining Left Ventricular Apex-to-Base Twist Mechanics Computed From High-Resolution 3D Echocardiography

Abstract: Despite lower spatiotemporal resolution of 3D echocardiography, LV twist and torsion can be computed accurately.

Cited by 43 publications

References 19 publications

Cardiac Assist With a Twist: Apical Torsion as a Means to Improve Failing Heart Function

Cardiac Assist With a Twist: Apical Torsion as a Means to Improve Failing Heart Function

3D Strain Assessment in Ultrasound (Straus): A Synthetic Comparison of Five Tracking Methodologies

Global longitudinal strain corrected by RR interval is a superior predictor of all‐cause mortality in patients with systolic heart failure and atrial fibrillation

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