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Articles by William M. Gottliebson in JoVE

 JoVE Clinical and Translational Medicine

Magnetic Resonance Härledda Myocardial Sila Uppskattning med hjälp av funktionen Spåra


JoVE 2356 2/12/2011

1The Heart Institute, Cincinnati Children Hospital Medical Center (CCHMC), 2TomTec, Imaging Systems GmbH, 3AMID, Advanced Medical Imaging Development SRL, 4The Heart and Vascular Center, The Christ Hospital

En korrekt och praktisk metod för att mäta parametrar som påfrestningar i myokardiet vävnad är av stort kliniskt värde eftersom det har visat, är att stam en mer känslig och tidigare markör för kontraktil dysfunktion än den ofta använda parametern EF.

Other articles by William M. Gottliebson on PubMed

A Rapid Hemodynamic Monitor of Acute Ischemia During Cardiac Procedures: Changes in Relaxation Via a Continuous Left Ventricular Pressure-derivative Loop

Procedures that induce ischemic pre-conditioning during cardiac surgery will require a rapidly visualized hemodynamic monitor of acute ischemia. This study investigated the utility of a continuous loop tracing of left ventricular pressure (LVP) plotted against its derivative (dP/dt) as a visual beat-to-beat monitor of acute changes in myocardial relaxation due to global ischemia.

Implementation of an Objective Testing System in Noninvasive Cardiac Imaging for Evaluation of Pediatric Cardiology Fellows

Current evaluation of pediatric cardiology fellow performance is subjective and qualitative. More objective tools are recommended by credentialing boards and may provide more effective evaluation and education.

Morphological Studies of Pulmonary Arteriovenous Shunting in a Lamb Model of Superior Cavopulmonary Anastomosis

We sought to identify and characterize the abnormal vascular structures responsible for pulmonary arteriovenous shunting following the Glenn cavopulmonary shunt. Superior cavopulmonary shunt is commonly performed as part of the staged pathway to total cavopulmonary shunt to treat univentricular forms of congenital heart disease, however, clinically significant pulmonary arteriovenous malformations develop in some patients after the procedure. The causes of pulmonary arteriovenous malformations and other pulmonary vascular changes that occur after cavopulmonary shunt are not known. Using a juvenile lamb model of superior cavopulmonary anastomosis that reliably produces pulmonary arteriovenous malformations, we performed echocardiography and morphological analyses to determine the anatomic site of shunting and to identify the vascular structures involved. Pulmonary arteriovenous shunting was identified by contrast echocardiography in all surviving animals (n = 40) following superior cavopulmonary anastomosis. Pulmonary vascular corrosion casts revealed abnormal tortuous vessels joining pulmonary arteries and veins in cavopulmonary shunt animals but not control animals. In conclusion, unusual channels that bridged pulmonary arteries and veins were identified. These may represent the vascular structures responsible for arteriovenous shunting following the classic Glenn cavopulmonary shunt. Detailed analysis of these structures may elucidate factors responsible for their development.

Late Gadolinium Enhancement: Precursor to Cardiomyopathy in Duchenne Muscular Dystrophy?

Progressive cardiomyopathy is a common cause of death in Duchenne muscular dystrophy (DMD), presumably secondary to fibrosis of the myocardium. The posterobasal and left lateral free wall of the left ventricle (LV) are initial sites of myocardial fibrosis pathologically. The purposes of this study were to assess whether cardiac magnetic resonance imaging (CMRI), utilizing late gadolinium enhancement (LGE), could identify fibrosis in selective areas of the myocardium, and to assess the relationship of the presence and extent of fibrosis to LV function.

Circumferential Strain Analysis Identifies Strata of Cardiomyopathy in Duchenne Muscular Dystrophy: a Cardiac Magnetic Resonance Tagging Study

This study sought to evaluate the natural history of occult cardiac dysfunction in Duchenne muscular dystrophy (DMD).

Concurrent Assessment of Epicardial Coronary Artery Stenosis and Microvascular Dysfunction Using Diagnostic Endpoints Derived from Fundamental Fluid Dynamics Principles

Simultaneously measured pressure and flow distal to coronary stenoses can be combined, in conjunction with anatomical measurements, to assess the status of both the epicardial and microvascular circulations.

Comparison of Magnetic Resonance Feature Tracking for Strain Calculation with Harmonic Phase Imaging Analysis

To compare a steady-state free precession cine sequence-based technique (feature tracking [FT]) to tagged harmonic phase (HARP) analysis for peak average circumferential myocardial strain (epsilon(cc)) analysis in a large and heterogeneous population of boys with Duchenne muscular dystrophy (DMD).

Left Ventricular T2 Distribution in Duchenne Muscular Dystrophy

Although previous studies have helped define the natural history of Duchenne muscular dystrophy (DMD)-associated cardiomyopathy, the myocardial pathobiology associated with functional impairment in DMD is not yet known.The objective of this study was to assess the distribution of transverse relaxation time (T2) in the left ventricle (LV) of DMD patients, and to determine the association of myocardial T2 heterogeneity to the severity of cardiac dysfunction. DMD patients (n = 26) and normal control subjects (n = 13) were studied by cardiovascular magnetic resonance (CMR). DMD subject data was stratified based on subject age and LV ejection fraction (EF) into the following groups: A (<12 years old, n = 12); B (>or=12 years old, EF or=12 years old, EF = 55%, n = 6). Controls were also stratified by age into Groups N1 (<12 years, n = 6) and N2 (>12 years, n = 5). LV mid-slice circumferential myocardial strain (epsilon cc) was calculated using tagged CMR imaging. T2 maps of the LV were generated for all subjects using a black blood dual spin echo method at two echo times. The full width at half maximum (FWHM) was calculated from a histogram of LV T2 distribution constructed for each subject.

Detection of Progressive Cardiac Dysfunction by Serial Evaluation of Circumferential Strain in Patients with Duchenne Muscular Dystrophy

The present study evaluated progressive cardiac dysfunction using serial circumferential strain (epsilon(cc)) measurements in patients with Duchenne muscular dystrophy (DMD). DMD is characterized by progressive cardiac dysfunction and myocardial fibrosis late in the disease process. We hypothesized that serial epsilon(cc) changes could be detected in individual patients with DMD during a time when the left ventricular ejection fraction (EF) changes are insignificant. Cardiac magnetic resonance imaging data from patients with DMD were evaluated. The left ventricular EF was calculated from steady-state free precession cine images and the composite epsilon(cc) measurement from tagged cine images. The serial epsilon(cc) and EF values for each patient were analyzed using the Wilcoxon sign rank test. Data from 51 patients with DMD (2 studies per patient, mean age at the initial study 11.8 +/- 3.5 years, range 7.4 to 25.4) were analyzed, with a mean interval between cardiac magnetic resonance studies of 15.6 +/- 6.0 months (range 6.2 to 28.1). In the interval between studies, the epsilon(cc) had decreased in all patients with DMD. The average decrease was 1.8 +/- 1.3 (p <0.001). However, the EF had decreased in 33 of the 51 patients and had increased in 18 of the 51 patients. On average, the EF decreased by 2.9 +/- 8.57% (p = NS). In conclusion, in patients with DMD, epsilon(cc) abnormalities indicate progression within a relatively short period when the EF changes were not significant. Serial epsilon(cc) measurements might provide reliable monitoring of the progression of DMD-associated cardiac dysfunction before overt heart failure develops, because it is more sensitive than the EF.

Right Ventricular Inefficiency in Repaired Tetralogy of Fallot: Proof of Concept for Energy Calculations from Cardiac MRI Data

Repaired tetralogy of Fallot (rTOF) patients develop right ventricular (RV) dilatation and dysfunction. To prevent their demise, pulmonary valve replacement is necessary, though appropriate timing for it is challenged by a paucity of reliable diagnostic parameters. In this pilot study, we hypothesized that stroke work (SW) and energy calculations would delineate the inefficiency of RV performance in rTOF. RV SW was calculated for both an rTOF and a normal subject by utilizing RV pressure and volume measurements obtained during cardiac catheterization and MRI studies. Energy transfer rate and ratio were computed at the main pulmonary artery (PA). Compared to the normal RV, the rTOF RV had higher operating pressure, lower computed SW (0.078 J vs. 0.115 J for normal), and higher negative energy transfer at the PA (0.044 J vs. 0.002 J for normal). Furthermore, the energy transfer ratio was nearly twice as high for the normal RV (1.06) as for the rTOF RV (0.56). RV SW and energy transfer ratio delineate important operational efficiency differences in blood flow from the RV to the PA between rTOF and normal subjects. Our pilot data suggest that the rTOF RV is significantly less efficient than normal.

Presence of Mechanical Dyssynchrony in Duchenne Muscular Dystrophy

Cardiac dysfunction in boys with Duchenne muscular dystrophy (DMD) is a leading cause of death. Cardiac resynchronization therapy (CRT) has been shown to dramatically decrease mortality in eligible adult population with congestive heart failure. We hypothesized that mechanical dyssynchrony is present in DMD patients and that cardiovascular magnetic resonance (CMR) may predict CRT efficacy.

Comparison of Hemodynamic Endpoints Between Normal Subject and Tetralogy Patient Using Womersley Velocity Profile and MR Based Flow Measurements

Right ventricular (RV) enlargement and pulmonary valve insufficiency (PI) are well-known, unavoidable long term sequelae encountered by patients who undergo tetralogy of Fallot (TOF) surgery. Despite their lifelong need for cardiac surveillance and occasional re-intervention, there is a paucity of numerical data characterizing blood flows in their pulmonary arteries (PA). Specifically, although PA regurgitation is well-known to be ubiquitously present in adult repaired TOF (rTOF) patients yet, there have been only limited numerical studies to fully characterize this process. The few studies available have utilized idealized, simplistic geometric models or overly simplistic boundary conditions that fail to account for flow reversals near the arterial walls as observed in in-vitro and MRI based in-vivo studies. The objective of this study was to establish and validate a numerical methodology of PA blood flow using actual patient specific geometry and flow measurements obtained using phase-contrast MRI, employing Womersley type velocity profiles that model flow reversals near walls. The results from computation were validated with measurements. For the normal subject, the time averaged right PA pressure from computation (13.8 mmHg) and experiment (14.6 mmHg) differed by 6%. The time-averaged main PA pressure from computation (16.5 mmHg) and experiment (16.3 mmHg) differed by 1%. The numerically computed left PA regurgitant fraction was 89% compared to measured 77.5%, while the same for the rTOF was 43% (computation), compared to 39.6% (measured). We conclude that the use of numerical computations using the Womersley boundary condition allows reliable modeling of the pathophysiology of PA flow in rTOF.

Effects of Steroids and Angiotensin Converting Enzyme Inhibition on Circumferential Strain in Boys with Duchenne Muscular Dystrophy: a Cross-sectional and Longitudinal Study Utilizing Cardiovascular Magnetic Resonance

Steroid use has prolonged ambulation in Duchenne muscular dystrophy (DMD) and combined with advances in respiratory care overall management has improved such that cardiac manifestations have become the major cause of death. Unfortunately, there is no consensus for DMD-associated cardiac disease management. Our purpose was to assess effects of steroid use alone or in combination with angiotensin converting enzyme inhibitors (ACEI) or angiotension receptor blocker (ARB) on cardiovascular magnetic resonance (CMR) derived circumferential strain (εcc).

Comparison of Stroke Work Between Repaired Tetralogy of Fallot and Normal Right Ventricular Physiologies

Adult patients who underwent tetralogy of Fallot repair surgery (rTOF) confront life-threatening ailments due to right ventricular (RV) myocardial dysfunction. Pulmonary valve replacement (PVR) needs to be performed to restore the deteriorating RV function. Determination of correct timing to perform PVR in an rTOF patient remains subjective, due to the unavailability of quantifiable clinical diagnostic parameters. The objective of this study is to evaluate the possibility of using RV body surface area (BSA)-indexed stroke work (SW(I)) to quantify RV inefficiency in TOF patients. We hypothesized that RV SW(I) required to push blood to the lungs in rTOF patients is significantly higher than that of normal subjects. Seven patients with rTOF pathophysiology and eight controls with normal RV physiology were registered for this study. Right ventricular volume and pressure were measured using cardiac magnetic resonance imaging and catheterization, respectively. Statistical analysis was performed to quantify the difference in SW(I) between the RV of the rTOF and control groups. Right ventricular SW(I) in rTOF patients (0.176 ± 0.055 J/m(2)) was significantly higher by 93.4% (P = 0.0026) than that of controls (0.091 ± 0.030 J/m(2)). Further, rTOF patients were found to have significantly higher (P < 0.05) BSA normalized RV end-systolic volume, end-systolic pressure, and regurgitation fraction than control subjects. Ejection fraction and peak ejection rate of rTOF patients were significantly lower (P < 0.05) than those of controls. Patients with rTOF pathophysiology had significantly higher RV SW(I) compared with subjects with normal RV physiology. Therefore, RV SW(I) may be useful to quantify RV inefficiency in rTOF patients along with currently used clinical end points such as RV volume, pressure, regurgitation fraction, and ejection fraction.

Patterns of Left Ventricular Remodeling in Patients with Duchenne Muscular Dystrophy: a Cardiac MRI Study of Ventricular Geometry, Global Function, and Strain

The cardiac disease ubiquitously associated in Duchenne Muscular Dystrophy (DMD) has traditionally been considered a progressive dilated cardiomyopathy (DCM). However, left ventricular (LV) dilatation as measured with cardiac MRI has not been a consistent finding in this population, even as circumferential strain (ε(cc)) declines with advancing disease. We hypothesized that a distinct pattern of changes in LV geometry, during the course of ε(cc) decline, distinguishes DMD associated heart disease from DCM. Using CMR, LV end-diastolic volume (EDV), mass (LVM), ejection fraction, ε(cc) and myocardial delayed enhancement (MDE) were determined in DMD patients and normal control subjects. The LV Remodeling Index (LVRI) was calculated as the ratio of LV Mass to Volume (LVM/EDV). Statistical comparisons between all LV parameters and genotype were also performed. Median LVRI in DMD (n = 127) and control subjects (n = 41) were different (0.75 vs. 0.65, P = 0.0150) but within normal range. Furthermore, the median LVRI in DMD boys with reduced LV systolic function was significantly reduced compared to those with normal LV systolic function (0.64 vs. 0.75, P = 0.0974). However, the presence of MDE was associated with a lower median LVRI (0.57 vs. 0.76, P = 0.0471). Regression analysis showed no significant correlation between ε(cc) and LVRI (r = -0.03). The LVRI of DMD patients is unexpectedly normal and not correlated with ε(cc.) Based on these findings, DMD-associated heart disease exhibits a unique remodeling pattern distinct from DCM.

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