Intrinsic indices of the left ventricle as a blood pump in normal and infarcted left ventricles

Subbaraj, K.; Ghista, Dhanjoo N.; Fallen, Ernest L.

doi:10.1016/0141-5425(87)90004-5

Cited by 15 publications

(5 citation statements)

References 4 publications

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“…The analysis is detailed in Subbaraj et al 29 Further, by comparing intra-LV pressure-gradient before and after administration of nitroglycerin (a myocardial perfusing agent, and hence a quasi-simulator of augmented perfusion of the ischemic myocardium, due to coronary bypass surgery), we can infer how the myocardium is going to respond and how these LV functional indices will improve after coronary-bypass surgery.…”

Section: Intra-lv Of Blood-flow Velocity and Pressure Distribution (Tmentioning

confidence: 99%

Measures and Indices for Intrinsic Characterization of Cardiac Dysfunction During Filling and Systolic Ejection

Liu

Ghista

et al. 2005

J. Mech. Med. Biol.

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The paper discusses the development and application of bioengineering indices for reliable diagnosis of cardiac functional modalities in filling and contraction phases.During diastolic filling, the left-ventricular (LV) volume developed is a response to left-atrium (LV) suction at early rapid filling and LA contraction at late filling. However, in LV ejection, the LV flow-rate and aortic pressure constitute response to LV myocardial stress and intra-LV pressure generation. The differential equations used in the governing of these relationships have been developed. By matching the solutions of these differential equations with the clinical data of LV volume and pressure, we can determine the heart model "differential equations" parameters, as well as the derived indices. These parameters and indices include: compliance and resistance-to-filling for characterizing diastolic-filling function, together with the index of LV contractility (in terms of maximum LV contractile power and stress-velocity relationship for contractile element). By evaluating them, it is possible to diagnose more reliably and differentially heart diseases due to an increase in filling-resistance and contractility abnormalities.

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Section: Intra-lv Of Blood-flow Velocity and Pressure Distribution (Tmentioning

confidence: 99%

Measures and Indices for Intrinsic Characterization of Cardiac Dysfunction During Filling and Systolic Ejection

Liu

Ghista

et al. 2005

J. Mech. Med. Biol.

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“…11À13 In parallel to non-invasive imaging techniques, computational°uid dynamics (CFD) has been used for examining the global°ow patterns and pressure distribution since the 1970s and 1980s. 14,15 The early models were con¯ned to one or two dimensions with simpli¯ed geometries. With the continuing development of high-performance computing, realistic geometries and°uidÀventricular wall interactions were subsequently incorporated into the CFD models to obtain velocity and pressure distributions in the LV, as well as stress distributions within the wall.…”

mentioning

confidence: 99%

Intra-Left Ventricular Flow Distributions in Diastolic and Systolic Phases, Based on Echo Velocity Flow Mapping of Normal Subjects and Heart Failure Patients, to Characterize Left Ventricular Performance Outcomes of Heart Failure

Tan

Huang

et al. 2012

J. Mech. Med. Biol.

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Heart failure (HF), one of the most common diseases in the world, causes left ventricular dysfunction (LV) and high mortality. HF patients are strati¯ed into two groups based on their LV ejection fraction (EF) À À À HF with normal EF (HFNEF) and with reduced EF (HFREF). EF is a commonly used measure of LV contractile performance. Despite preserved EF, a complex mixture of systolic and diastolic dysfunction and variable degrees of LV remodelling underlying HFNEF poses challenges to diagnose and provide pharmacological treatment for HFNEF. In recent years, the velocity°ow mapping (VFM) technique has been developed to generate°ow velocity vector elds by post-processing color Doppler echocardiographic (echo) images. We aim to obtain the intra-LV blood°ow patterns for patients with HFNEF, HFREF, and normal subjects, in order to characterize the LV performance outcomes of normal subjects and HF patients.Two subjects from each group of HFNEF, HFREF, and normal underwent echo scans. Velocity vector distributions throughout the cardiac cycle were then analysed using the VFM technique. In each subject, the out°ow rate during systole, in°ow rate during diastole, as well as wall stress-based pressure-normalized contractility index, d Ã =dt max , were computed and compared among the groups.This study demonstrated the use of VFM to visualize LV blood°ow patterns in HF patients and normal subjects. Di®erent patterns of°ow distributions were observed in these subjects. In HFREF patients, d Ã =dt max , the peak out°ow rate and peak in°ow rate during early¯lling were § Corresponding author. . Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY -SERIALS UNIT on 03/08/15. For personal use only. markedly reduced. In HFNEF patients, peak out°ow rates were increased compared to those of normal subjects.

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“…Nanyang Technological University Library x Cardiac magnetic resonance (CMR) imaging has been used for examining detailed blood flow patterns in the heart and great vessels for a range of clinical conditions [6][7][8]. In parallel to noninvasive imaging techniques, computational fluid dynamics (CFD) has been used for examining the global flow patterns and pressure distribution since the 1970s and 1980s [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…Computational fluid dynamics (CFD) has been used for examining the global flow patterns and pressure distributions since the 1970s and 1980s using simplified geometries [9,10]. With the development of high-performance computing, realistic geometries and fluid-ventricular wall interactions were subsequently incorporated into the CFD models [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…The vortex flow that forms during left ventricular filling is a critical determinant of direct blood flow during ejection, and can offer a novel index of cardiac dysfunction.CMR has been used for examining detailed blood flow patterns in the heart and great vessels for a range of clinical conditions[6][7][8]. In parallel with non-invasive imaging techniques, computational fluid dynamics (CFD) has been used for examining the global flow patterns and pressure distribution since the 1970s and 1980s[9,10]. The early models were confined to oneor two-dimensions with simplified geometries and fluid-ventricular wall interactions were subsequently incorporated into the CFD models to obtain velocity and pressure distributions in the LV, as well as stress distributions within the wall[11][12][13].However, CMR is relatively expensive and not readily available.…”

mentioning

confidence: 99%

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Intra-left ventricular blood flow analysis to determine cardiac performance and dysfunction indices

Le¹

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changes with ageing and progressive impairment of diastolic function. In chapter 4, to evaluate the change in LA haemodynamic and its contribution to LV diastolic performance, an intrinsic LA contractility index, termed maximum LA ejection force (LAEjFmax), was formulated and compared in patients with HFrEF, HFpEF with different severity of diastolic dysfunction, versus ageing and young healthy controls. Load-adjusted LAEjFmax showed negative correlation with ageing and severity of diastolic dysfunction. Next, in chapter 5, maximum LV ejection force (LVEjFmax) was formulated and proposed as an index for LV contractile performance. Preload-adjusted LVEjFmax showed good correlations with conventional indices of systolic performance. It also had an exponential relationship with cardiac injury, assessed by blood biomarker Troponin T. From the flow vectors, intra-LV pressure gradient distributions were also computed in chapter 6. Although comprehensive validation studies are required, this proposed method makes study of non-invasive intra-LV haemodynamic in large number of patients with various disease conditions possible in the clinical settings where high throughput is desired. Lastly, in chapter 7, to gain insights into changes in LV stiffness in HF, extracellular volume fraction (ECV) measurement, which is believed to correlate with myocardial fibrosis, from magnetic resonance T1-mapping native-and post-contrast images. An algorithm to calculate pixel-wise ECV map of LV myocardium was developed and tested in a normal control and a diseased subject. Conclusion and future directions are highlighted in Chapter 8. In addition, clinical application of using contractility index for detection of early stage of siderotic cardiomyopathy is included in the Appendix.

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Intrinsic indices of the left ventricle as a blood pump in normal and infarcted left ventricles

Cited by 15 publications

References 4 publications

Measures and Indices for Intrinsic Characterization of Cardiac Dysfunction During Filling and Systolic Ejection

Measures and Indices for Intrinsic Characterization of Cardiac Dysfunction During Filling and Systolic Ejection

Intra-Left Ventricular Flow Distributions in Diastolic and Systolic Phases, Based on Echo Velocity Flow Mapping of Normal Subjects and Heart Failure Patients, to Characterize Left Ventricular Performance Outcomes of Heart Failure

Intra-left ventricular blood flow analysis to determine cardiac performance and dysfunction indices

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