Quantitative Three-Dimensional Wall Motion Analysis Predicts Ischemic Region Size and Location

Herz, Susan L.; Hasegawa, Takuya; Makaryus, Amgad N.; Parker, Katherine M.; Homma, Shunichi; Wang, Jie; Holmes, Jeffrey W.

doi:10.1007/s10439-009-9880-1

Cited by 11 publications

(36 citation statements)

References 37 publications

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“…As selecting a threshold for defining this abnormal flow is not straightforward, multiple potential thresholds were tested. Previous work in supply ischemia 77 For all of these measures, the mean size of the PD changed but correlation with the wall motion abnormality size did not, as detailed in Chapter 4. It seems the choice of threshold just determines how much of the border zone to include in PD size.…”

Section: Definition Of Perfusion Defectmentioning

confidence: 91%

“…77 Twelve images were acquired after two minutes of transient occlusion of either LAD or left circumflex (LCx) arteries in a proximal or distal location, and 12 were acquired during normal function immediately prior to occlusion. ED and ES time points…”

Section: Methodsmentioning

confidence: 99%

“…Our lab has developed a 3D measure of wall motion, three-dimensional fractional shortening (3DFS), which can accurately detect the size and location of a region with acute supply ischemia. 77 While these new analysis methods show promise for increasing the amount of information available from 3DE, there is limited information on how well each measure actually detects demand ischemia. The efficacy of each measure for detecting disease must be evaluated clinically before this research is adopted into clinical use.…”

Section: Echocardiographymentioning

confidence: 99%

“…This resulted in 60 transmural blocks evenly distributed over the LV surface (Figure 2.2C), as used in previous experiments. 77 Tissue mass and regional myocardial blood flow was determined for each block using standard methods for quantification of radioactive microspheres. 81 …”

Section: Assessment Of Regional Myocardial Blood Flowmentioning

confidence: 99%

“…77,78,80 The endocardial data were transformed into a cardiac coordinate system using the three anatomical landmarks selected at ED. This cardiac coordinate system has axes directed parallel to the base-apex axis (x 1 ), through the midseptum (x 2 ), and through the posterior wall (x 3 ) from an origin located 1/3 of the distance from the base to apex along the LV long axis.…”

Section: Fittingmentioning

confidence: 99%

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Regional Mechanics of Demand Ischemia During Cardiac Stress Testing

Parker

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Currently, the most effective non-invasive method for early diagnosis of coronary artery disease is the cardiac stress test. In this test, stress is induced by treadmill exercise or with a pharmacologic agent such as dobutamine, and myocardium with insufficient coronary flow reserve, usually caused by coronary stenosis, experiences an imbalance between oxygen supply and demand known as demand ischemia. This causes altered mechanical and electrical behavior that is often identified using cardiac imaging. The mechanical movement of the left ventricular (LV) wall, characterized clinically as "wall motion", is currently assessed qualitatively to identify abnormally-moving ischemic regions which may benefit from angioplasty. Advances in ultrasound and MRI may improve diagnosis by allowing more quantitative measures such as strain, wall thickening, or endocardial fractional shortening. However, little is understood about how these measures are affected by the severity of demand ischemia, coupling to adjacent myocardium, or the presence of previously-unrecognized myocardial infarction. A greater understanding of the factors that influence regional mechanics during stress testing would help determine the best way to detect the altered mechanics that indicate demand ischemia and coronary stenosis. The goal of this dissertation is to understand how regional demand ischemia affects regional mechanics and apply that knowledge to improve clinical stress testing.A finite element model of the heart was used to examine how reduced force generation in the ischemic region, ischemic region size, and coupling to myocardium with increased contractility separately and jointly impact various measures of regional mechanics. Area strain and a measure of wall motion developed in our lab, threeiv dimensional fractional shortening (3DFS), were most sensitive to reduced force generation, while radial strain was affected most by the contractility of remote myocardium. The model also predicted that a novel measure of wall motion bulging, dyskinesia severity index (DSI), can separate infarcts from demand ischemia during stress testing. The ability of strain and 3DFS to detect a critical stenosis was evaluated in experimental canine dobutamine stress tests. The three-dimensional (3D) measures of area strain and 3DFS detected critical stenoses better than two-dimensional (2D) strain. Finally, 3DFS measured during clinical stress testing in patients at low risk for coronary artery disease displayed low variability, suggesting 3DFS may be effective for detecting demand ischemia in patients.Another application in which the cardiac mapping techniques described here could improve treatment is in evaluating cardiac resynchronization therapy (CRT) nonresponders, which compromise 30-40% of CRT patients. The relationship between LV lead location and scar or regional mechanical function measured from pre-CRT cardiac imaging likely has an important impact on CRT response. A method to reconstruct the 3D coordinates of the lead from 2D fluoroscopic i...

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Section: Definition Of Perfusion Defectmentioning

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Section: Echocardiographymentioning

confidence: 99%

Section: Assessment Of Regional Myocardial Blood Flowmentioning

confidence: 99%

Section: Fittingmentioning

confidence: 99%

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