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Strotmann, Jörg; Hatle, Liv; Sutherland, George R.

doi:10.1023/a:1010679522539

Cited by 9 publications

(2 citation statements)

References 41 publications

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“…As such, improved regional assessment of temporal changes throughout the myocardium may enhance clinical evaluation of the rate and extent of the post-MI remodeling process. In vivo regional mechanical behavior has been assessed post-MI in both basic scientific and clinical studies using techniques such as sonomicrometry, cardiac magnetic resonance imaging, and tissue Doppler-derived imaging (16,33,34,37,40,41,45). Although these and other approaches have yielded critical information on the post-MI remodeling process, they have not been uniformly applied to assess LV regional function across the entire chamber and in a serial fashion because of several factors.…”

Section: Introductionmentioning

confidence: 99%

“…In clinical studies, noninvasive approaches such as cardiac magnetic resonance imaging can provide high-fidelity regional assessment of LV function, but lengthy acquisition and postprocessing times make it impractical to collect repeated measurements (45). Tissue Doppler-derived imaging has also been applied in both large animal models and clinical settings to quantify regional myocardial strain with reported limitations stemming from a significant dependency on the angle of the ultrasound beam and low signal-to-noise ratio (37,40,41).…”

Section: Introductionmentioning

confidence: 99%

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Regional and temporal changes in left ventricular strain and stiffness in a porcine model of myocardial infarction

Torres

Jacobs

Doviak

et al. 2018

American Journal of Physiology-Heart and Circulatory Physiology

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The aim of the present study was to serially track how myocardial infarction (MI) impacts regional myocardial strain and mechanical properties of the left ventricle (LV) in a large animal model. Post-MI remodeling has distinct regional effects throughout the LV myocardium. Regional quantification of LV biomechanical behavior could help explain changes in global function and thus advance clinical assessment of post-MI remodeling. The present study is based on a porcine MI model to characterize LV biomechanics over 28 days post-MI via speckle-tracking echocardiography (STE). Regional myocardial strain and strain rate were recorded in the circumferential, radial, and longitudinal directions at baseline and at 3, 14, and 28 days post-MI. Regional myocardial wall stress was calculated using standard echocardiographic metrics of geometry and Doppler-derived hemodynamic measurements. Regional diastolic myocardial stiffness was calculated from the resultant stress-strain relations. Peak strain and phasic strain rates were nonuniformly reduced throughout the myocardium post-MI, whereas time to peak strain was increased to a similar degree in the MI region and border zone by 28 days post-MI. Elevations in diastolic myocardial stiffness in the MI region plateaued at 14 days post-MI, after which a significant reduction in MI regional stiffness in the longitudinal direction occurred between 14 and 28 days post-MI. Post-MI biomechanical changes in the LV myocardium were initially limited to the MI region but nonuniformly extended into the neighboring border zone and remote myocardium over 28 days post-MI. STE enabled quantification of regional and temporal differences in myocardial strain and diastolic stiffness, underscoring the potential of this technique for clinical assessment of post-MI remodeling. NEW & NOTEWORTHY For the first time, speckle-tracking echocardiography was used to serially track regional biomechanical behavior and mechanical properties postmyocardial infarction (post-MI). We found that changes initially confined to the MI region extended throughout the myocardium in a nonuniform fashion over 28 days post-MI. Speckle-tracking echocardiography-based evaluation of regional changes in left ventricular biomechanics could advance both clinical assessment of left ventricular remodeling and therapeutic strategies that target aberrant biomechanical behavior post-MI.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Regional and temporal changes in left ventricular strain and stiffness in a porcine model of myocardial infarction

Torres

Jacobs

Doviak

et al. 2018

American Journal of Physiology-Heart and Circulatory Physiology

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Tissue Doppler imaging for detecting onset of muscle activity

et al. 2008

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Tissue Doppler imaging (TDI) is typically used to image and quantify tissue motion. We investigated whether this method would serve as a viable alternative to surface electromyography (EMG) in providing a reliable and valid measure of the onset of muscle activity. Ten healthy subjects performed maximal knee extension exercises at 0 degrees /s (isometric), 60 degrees /s, 120 degrees /s, 180 degrees /s, and 240 degrees /s (5 times each, on each side), using an isokinetic dynamometer. Simultaneous EMG and TDI velocity (superimposed on motion-mode ultrasound cine-loops) recordings were made from vastus lateralis. All tests were repeated 1 week later. There was a good correlation between the onset times determined with TDI velocity and EMG: r = 0.78 (day 1), and r = 0.80 (day 2) (each P < 0.001). The mean difference (and SD) in muscle onset time between the two methods (TDI minus EMG) was -20.3 +/- 31.0 ms (day 1) and -17.4 +/- 27.2 ms (day 2). TDI represents a reliable and valid measure of detecting onset of muscle activity. The mean difference between EMG and TDI onset times (approximately 20 ms) is likely explained by electromechanical delay. TDI represents a viable method for measuring the onset of muscle activity; it may offer a non-invasive alternative to fine-wire EMG for use with small or deep muscles.

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