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Wall Motion (wall + motion)

Distribution by Scientific Domains

Medical Sciences	80%
6 Other Domains	20%

Kinds of Wall Motion

regional wall motion

Terms modified by Wall Motion

wall motion abnormality

wall motion score index

Selected Abstracts

Right Ventricular Function in Congenital Heart Defects Assessed by Regional Wall Motion

CONGENITAL HEART DISEASE, Issue 3 2010
FSCAI, Michael R. Nihill MB
ABSTRACT Objectives., To develop a simple method to assess right ventricular function by angiography. Background., Conventional methods of evaluating right ventricular function are inaccurate, cumbersome, and expensive. Methods., We analyzed biplane right ventricular angiograms taken in the posterior,anterior and lateral projections using software to measure right ventricular volumes and regional wall motion in 78 patients with normal hearts (n = 29), atrial septal defects (ASD n = 13), pulmonary valve stenosis (PVS n = 21), and postoperative atrial switch patients (n = 15). We also measured the shortening fraction (SF) from the midtricuspid annulus to the septum and correlated various angiographic measurements with the right ventricular (RV) ejection fraction. Results., The volume-overloaded patients (ASD) had larger end diastolic volumes and increased SF compared with normal patients, while the pressure-loaded patients (PVS) had normal volumes and SF. The postoperative atrial switch patients had decreased systolic function and increased end diastolic volume. The SF for all of the patients correlated with the ejection fraction (r= 0.785, P, .0001). Conclusions., A simple measurement of the end diastolic and end systolic distance from the midtricuspid annulus to the septum (SF) provides a good index of RV function by angiography and correlates well with RV ejection fraction. [source]

Time course of 23Na signal intensity after myocardial infarction in humans

MAGNETIC RESONANCE IN MEDICINE, Issue 3 2004
Joern J.W. Sandstede
Abstract Experimental studies demonstrated persistently increased 23Na content in nonviable myocardium post-myocardial infarction (MI). We hypothesized that nonviable myocardium in humans would show elevated 23Na content at all stages of infarct development, and therefore could be imaged with 23Na MRI. Ten patients were examined on days 4, 14, and 90 after infarction, and five of these patients participated in a 12-month follow-up. Double angulated short-axis cardiac 23Na images were obtained with the use of a 23Na surface coil and an ECG-triggered, 3D gradient-echo sequence. 1H T2 -weighted imaging (N = 9) was performed on days 4, 14, and 90. Wall motion was assessed by cine MRI, and the infarct size was determined by late enhancement on day 90. The 23Na signal intensity (SI) of infarcted myocardium was expressed as the percentage increase over 23Na SI of noninfarcted myocardium. All of the patients showed an area of elevated SI on 23Na and 1H T2 -weighted images that correlated with wall motion abnormalities and late enhancement. 23Na SI was highest on day 4. It then decreased until day 90, but remained elevated (39% ± 18%, 31% ± 17%, 28% ± 13% on days 4, 14, and 90, respectively, P = 0.001). No further decrease was found 1 year after infarction (25% ± 7%, P = 0.89 vs. day 90). 1H T2 -weighted SI decreased between days 4 and 14, but on day 90 only six of nine patients had a residual elevated SI. Thus, 23Na SI is elevated in nonviable infarction at all time points following MI, and 23Na MRI may become a suitable technique for imaging nonviable myocardium in humans. Magn Reson Med 52:545,551, 2004. © 2004 Wiley-Liss, Inc. [source]

Motion visualization of human left ventricle with a time-varying deformable model for cardiac diagnosis

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 2 2001
Soo-Mi Choi
Abstract We present a time-varying deformable model to visualize and analyze the motion of the left ventricle from a time series of 3-D images. The model is composed of a non-rigid body that deforms around a reference shape obtained from the previous time step. At each time step, the position and orientation of the left ventricle are extracted from the feature points of images. This information gives the position and orientation of the coordinate system attached to the non-rigid body. To compute a dense non-rigid motion field over the entire endocardial wall of the left ventricle, we introduce a 3-D blob finite element and Galerkin interpolants based on 3-D Gaussian, and use a physically based finite element method and a modal analysis. Then, cinematic attributes are visualized in pseudo colors on the reconstructed surface in order to help medical doctors in their interpretation of the data. Using the presented model, we estimate clinically useful quantitative parameters such as regional wall motion and ejection fraction. Experimental results are shown in a time series of X-ray angiographic images. Copyright ©2001 John Wiley & Sons, Ltd. [source]

Right Ventricular Function in Congenital Heart Defects Assessed by Regional Wall Motion

Resting Echocardiography for the Early Detection of Acute Coronary Syndromes in Chest Pain Unit Patients

ECHOCARDIOGRAPHY, Issue 6 2010
Vito Maurizio Parato M.D.
Aim: The purpose of this study is to assess the ability of resting echocardiography to detect an acute coronary syndrome (ACS) before the occurrence of ischemic electrocardiogram (ECG) changes or troponin-T elevations. Methods: Four hundred and three patients who presented to the emergency room (ER) with chest pain, normal ECGs, and normal troponin-T levels were admitted to the cardiologist-run Chest Pain Unit (CPU) for further monitoring. They underwent serial resting echocardiography for monitoring of left ventricle wall motion (LVWM), ECG telemetry monitoring, and serial troponin-T measurements. Results: An ACS was detected in 49 patients (12.1%). These 49 patients were then subdivided into three different groups based on the initial mode of detection of their ACS. In group A, 16 of 49 (32.6%) patients had ACS shown by echocardiographic detection of LVWM abnormalities. In group B, 24 of 49 (48.9%) patients had an ACS detected by ischemic ECG changes. In group C, 9 of 49 (18.3%) patients had an ACS detected by troponin-T elevations. The shortest time interval between CPU-admission and ACS-detection occurred in group A (A vs. B, P < 0.003; A vs. C, P < 0.0001). In group A, cardiac angiogram showed that the culprit coronary lesion was more frequent in the circumflex artery (11 out of 16; 68.7%) (LCx vs. LAD, P < 0.02; LCx vs. RCA, P < 0.001) and of these 11 patients with circumflex lesions, the ECG was normal in eight (72.7%) patients. Conclusion: This study demonstrates the utility of LVWM monitoring by serial echocardiography as part of a diagnostic protocol that can be implemented in a CPU. Furthermore, echocardiography could become an essential tool used in the diagnosis of ACS secondary to circumflex lesions. (Echocardiography 2010;27:597-602) [source]

Assessment of Residual Viability by Enoximone Echocardiography in Patients with Previous Myocardial Infarction Correlation with Positron Emission Tomographic Studies and Functional Follow-Up

ECHOCARDIOGRAPHY, Issue 5 2010
Fei Lu M.D.
Background: The aim of this study was to evaluate enoximone echocardiography (EE) for the identification of residual myocardial viability in postinfarction patients. Findings obtained during EE were compared with those acquired by myocardial uptake of fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and functional follow-up results. Methods: Twenty-five patients underwent EE and PET 18F-FDG studies. An asynergic segment was considered as having contractile enhancement when the wall motion score decreased by ,1 grade during EE and was defined as viable if 18F-FDG uptake score was ,2 grade on PET. Results: Of 293 dysfunctional segments at baseline, 139 (47%) were viable by PET criteria; 117 (40%) had contractile enhancement induced by enoximone (P = 0.07). Agreement between EE and PET was found in 75% of involved segments (K = 0.46, P < 0.001). The majority of discrepancies (65%, P < 0.01) were mainly due to discordant segments in which PET revealed evidence of 18F-FDG uptake but EE showed no change in wall motion. In 179 revascularized segments, negative predictive value for functional recovery of both tests reached the same value (89% for both), whereas positive predictive value was 82% for EE and 68% for PET, respectively (P < 0.05). Sensitivity was 85% for EE and 88% for PET (P = ns); specificity was 87% and 70%, respectively (P < 0.01). Conclusions: EE yields a fair concordance with PET study. Compared with PET, despite a similar negative accuracy, EE shows a greater specificity for prediction of function recovery after revascularization. (Echocardiography 2010;27:544-551) [source]

Hand-Held Echocardiogram Does Not Aid in Triaging Chest Pain Patients from the Emergency Department

ECHOCARDIOGRAPHY, Issue 6 2009
Mayank Kansal M.D.
Background: Accurate triage of emergency department (ED) patients presenting with chest pain is a primary goal of the ED physician. In addition to standard clinical history and examination, a hand-held echocardiogram (HHE) may aid the emergency physician in making correct decisions. We tested the hypothesis that an HHE performed and interpreted by a cardiology fellow could help risk-stratify patients presenting to the ED with chest pain. Methods: ED physicians evaluated 36 patients presenting with cardiovascular symptoms. Patients were then dispositioned to either an intensive care bed, a monitored bed, an unmonitored bed, or home. Following disposition, an HHE was performed and interpreted by a cardiology fellow to evaluate for cardiac function and pathology. The outcomes evaluated (1) a change in the level of care and (2) additional testing ordered as a result of the HHE. Results: The HHE showed wall motion abnormalities in 31% (11 out of 36) of the studies, but the level of care did not change after HHE for any patients who presented with chest pain to the ED. No additional laboratory or imaging tests were ordered for any patients based on the results of the HHE. Eighty-six percent (31 out of 36) of the studies were of adequate quality for interpretation, and 32 out of 36 (89%) interpretations correlated with an attending overread. Conclusion: Despite the high prevalence of abnormal wall motion in this population, hand-held echocardiography performed in this ED setting did not aid in the risk stratification process of chest pain patients. (ECHOCARDIOGRAPHY, Volume 26, July 2009) [source]

Clinical Assessment and Rest and Stress Echocardiography for Prediction of Long-Term Prognosis in African Americans with Known or Suspected Coronary Artery Disease

ECHOCARDIOGRAPHY, Issue 5 2009
Stephen G. Sawada M.D.
Background: There is limited information on noninvasive risk stratification of African Americans, a high-risk group for cardiovascular events. We investigated the value of clinical assessment and echocardiography for the prediction of a long-term prognosis in African Americans. Methods: Dobutamine echocardiography was performed in 324 African Americans. Two-dimensional measurements were performed at rest, and rest and stress wall motion was assessed. A retrospective follow-up was conducted for cardiac events: myocardial infarction (MI) or cardiac death (CD). Results: The mean age was 59 ± 12 years, and 83% of patients had hypertension. The follow-up was obtained in 318 (98%) patients for a mean of 5.3 years. The events occurred in 107 (33%) subjects. The independent predictors of events were history of MI (P = 0.001, risk ratio [RR] 2.04), ischemia (P = 0.007, RR 1.97), fractional shortening (P = 0.033, RR 0.08), and left atrial (LA) dimension (P = 0.034, RR 1.39). An LA size of 3.6 cm and a fractional shortening of 0.30 were the best cutoff values for the prediction of events. Prior MI, ischemia, LA size >3.6 cm, and fractional shortening <0.30 were each considered independent risk predictors for events. The event rates were 13%, 21%, 38%, 59%, and 57% in patients with 0, 1, 2, 3, and 4 risk predictors, respectively. Event-free survival progressively worsened with an increasing number of predictors: 0 or 1 versus 2 predictors, P < 0.001; 2 versus 3 or 4 predictors, P = 0.003. Conclusion: The long-term prognosis of African Americans can be accurately predicted by clinical assessment combined with rest and stress echocardiography. [source]

Risk Stratification and Prognosis in Octogenarians Undergoing Stress Echocardiographic Study

ECHOCARDIOGRAPHY, Issue 8 2007
F. A. C. C., Farooq A. Chaudhry M.D.
Background: The prognostic value of stress echocardiography (SE) for the diagnosis and risk stratification of coronary artery disease in octogenarians is not well defined. Methods: Follow-up of 5 years (mean 2.9 ± 1.0 years) for confirmed nonfatal myocardial infarction (n = 17) and cardiac death (n = 37) was obtained in 335 patients, age ,80 years (mean age 84 ± 3 years, 44% male), undergoing SE (33% treadmill, 67% dobutamine). Left ventricular (LV) regional wall motion was assessed by a consensus of two echocardiographers and scored as per standard five-point scale, 16-segment model of wall motion analysis. Ischemic LV wall segment was defined as deterioration in the thickening and excursion during stress (increase in wall-motion score index (WMSI) ,1). Results: By univariate analysis, inducible ischemia (chi-square = 38.4, P < 0.001), left ventricular ejection fraction (chi-square = 41.2, P < 0.001), a history of previous myocardial infarction (chi-square = 22.3, P < 0.01), hypertension (chi-square = 33, P < 0.01), and age (chi-square = 27.7, P < 0.01) were significant predictors of future cardiac events. WMSI, an index of inducible ischemia, provided incremental prognostic information when forced into a multivariable model where clinical and rest echocardiography variables were entered first. WMSI effectively stratified octogenarians into low- and high-risk groups (annualized event rates of 1.2 versus 5.8%/year, P < 0.001). Conclusions: Stress echocardiography yields incremental prognostic information in octogenarians and effectively stratifies them into low- and high-risk groups. Precise therapeutic decision making in very elderly patients should incorporate combined clinical and stress echocardiography data. [source]

Echocardiographic Follow-Up of Patients with Takayasu's Arteritis: Five-Year Survival

ECHOCARDIOGRAPHY, Issue 5 2006
María Elena Soto M.D, Ms.Sc.
Takayasu's arteritis (TA) is a primary vasculitis that causes stenosis or occlusion, rarely aneurysm and distal ischemia. This study was undertaken to examine cardiovascular damage using echocardiography and determine the causes of morbid-mortality in Mexican Mestizo patients with TA. Seventy-six patients were studied by transthoracic echocardiography. Left ventricular diameters, parietal thickness, systolic function, and wall motion were analyzed, also, valvular lesions and aorta features were assessed. Thickness of the interventricular septum was 12 mm ± 3 (8,19), and that of posterior wall was 12 mm ± 2 (9,18). The average left ventricular diastolic diameter was 47 mm ± 7 (33,68) and the left ventricular systolic diameter 32 mm ± 8 (16,64). The left ventricular ejection fraction was of 57 ± 11%. Left ventricular concentric hypertrophy was found in 28 (50%) of the 56 hypertensive patients. The five-year survival of patients with left ventricular concentric hypertrophy was 80%, compared to 95% in patients without hypertrophy (P = 0.00). Abnormal wall motion was found in 15 patients. Thirty-one patients had aortic regurgitation, 19 had mitral regurgitation, 13 had tricuspid regurgitation, and 10 and pulmonary hypertension. Six patients had aneurysms of ascending aorta and 7 stenosis of descending aorta. Thirteen of 76 patients died (17%), 85% were hypertensive, and 9% also had acute myocardial infarction (AMI). Echocardiography, a noninvasive technique, shows a great utility in detection and follow-up of cardiovascular manifestations in patients with TA. New techniques, more sensitive toward detecting the early stages of left ventricular dysfunction, are promising to limit left ventricular hypertrophy development. [source]

Regional Response of Myocardial Acceleration During Isovolumic Contraction During Dobutamine Stress Echocardiography: A Color Tissue Doppler Study and Comparison with Angiocardiographic Findings

ECHOCARDIOGRAPHY, Issue 10 2005
Linda B. Pauliks M.D.
Background: Color tissue Doppler imaging permits noninvasive quantitation of regional wall motion. In experimental studies, a new marker, the slope of the isovolumic contraction wave, isovolumic acceleration (IVA) was more insensitive to ventricular loading conditions than myocardial velocities. This study compared the regional response IVA to dobutamine stress echocardiography to angiographic findings. Methods: The Myocardial Doppler in Stress Echocardiography (MYDISE) study prospectively recruited 149 consecutive patients with chest pain for dobutamine stress tissue Doppler echocardiography prior to coronary angiography. This color tissue Doppler database was analyzed for IVA in 1192 basal and mid segments at rest and again at peak stress. Angiographic findings were compared to IVA and peak systolic velocities (PSV) in corresponding cardiac segments. The diagnostic accuracy of IVA to predict coronary artery stenosis was determined using cut-off values for three representative segments and with the MYDISE diagnostic model including eight segments. Results: Regional IVA increased in a dose-dependent manner during dobutamine infusion. The response was blunted in the supply territory of stenosed coronary artery branches. IVA performed slightly better than PSV as single marker for coronary artery stenosis. A diagnostic model incorporating IVA and PSV was 85,95% accurate (area under receiver operating characterstic curves). Conclusions: Regional changes of isovolumic acceleration during dobutamine stress echocardiography reflect regional wall motion and can be used to predict coronary artery stenosis with similar accuracy as a model based on systolic myocardial velocities. As a single marker, IVA performed better than myocardial velocities. (ECHOCARDIOGRAPHY, Volume 22, November 2005) [source]

Close Physical Contact of the Heart with Diaphragm Causes Pseudo-Asynergy of Left Ventricular Inferior Wall in Normal Subjects

ECHOCARDIOGRAPHY, Issue 7 2004
Susumu Sakurai Ph.D.
Paradoxical outward movement of left ventricular (LV) inferior wall in systole is occasionally recognized in normal subjects and clinically important in terms of the differential diagnosis between physiological pseudo-asynergy and pathological asynergy. In this study, the potential mechanisms by which pseudo-asynergy of LV inferior wall (PLI) is observed in normal subjects were investigated. PLI was defined as the outward movement of LV inferior wall observed during more than 50% of systole. The incidence of PLI was evaluated in 7843 consecutive subjects in routine echocardiography. The effects of body position and artificial gravity on the manifestation of PLI were also examined. PLI was observed in 0.11% (9/7842) of subjects on left lateral position. Measurement of the angle formed by LV long-axis and the long-axis of the body on frontal plane revealed that hearts in subjects with PLI were in relatively horizontal position. PLI was observed on sitting position in 43% (40/92) of subjects without PLI on left lateral position. The subjects with sitting position-induced PLI exhibited significantly higher obesity index. PLI was also induced by artificial gravity in 67% (14/21) of healthy volunteers on supine position, and the degree of PLI correlated with the intensity of gravity. Although the incidence of PLI in routine echocardiography is relatively low, PLI can be induced in normal subjects by any condition that causes close contact of LV inferior wall to diaphragm. Thus, PLI should be taken into consideration in the differential diagnosis of abnormal LV inferior wall motion, especially when performing exercise echocardiography. [source]

Analysis of Left Atrial Volume Change Rate for Evaluation of Left Ventricular Diastolic Function

ECHOCARDIOGRAPHY, Issue 7 2004
F.E.S.C., Ming-Jui Hung M.D.
An excellent correlation exists between the change in the left atrial (LA) angiographic area and posterior aortic wall motion. The aim of the study was to define the role of posterior aortic wall motion, indicating LA volume change, during the left ventricular (LV) phase for the assessment of LV diastolic function. A total of 155 patients underwent echocardiography after cardiac catheterization. Study patients were classified into four groups according to the ratio of early-to-late transmitral flow velocity (E/A ratio) and/or LV end-diastolic pressure (EDP): 42 patients with LVEDP < 15 mmHg and E/A ratio >1 (normal filling); 46 patients with E/A < 1 (impaired relaxation); 46 patients with LVEDP , 15 mmHg and E/A > 1 and <2 (pseudonormal filling); 21 patients with E/A > 2, E , 70 cm/s, and E-wave deceleration time ,160 ms (restrictive filling). The slopes of early and late (slopes E and A) diastolic motion of LA wall were derived from M-mode analysis, together with the LV isovolumic time constant Tau from cardiac catheterization. Values of slope E/A decreased in restrictive filling, pseudonormal filling, and impaired relaxation as compared with normal filling (0.41 ± 0.14, 0.69 ± 0.15, and 0.56 ± 0.23 vs 1.25 ± 0.26, P < 0.001, respectively) and correlated inversely with the isovolumic time constant Tau (r = 0.79, P < 0.001). In cases for which a value of slope E/A < 1 was obtained, indicating a relaxation abnormality, the M-mode derived pattern of LA wall motion identified the underlying abnormal LV diastolic function with a sensitivity of 98.3%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 95.2%. Analysis of the slope of LA wall motion, indicating LA volume change rate, during LV diastolic phase is useful in evaluating LV diastolic function. It provides a new noninvasive index that correlates well with invasive index of LV relaxation. [source]

Role of Intravenous Ultrasound Contrast in Stress Echocardiography

ECHOCARDIOGRAPHY, Issue 1 2000
F.A.C.C., THOMAS R. PORTER M.D.
Intravenous newer generation perfluorocarbon containing microbubbles have been shown to enhance endocardial borders, especially during harmonic imaging. Although this significantly improves the detection of wall-motion abnormalities during stress echocardiography, intermittent imaging consistently results in myocardial contrast following intravenous infusions or injections of perfluorocarbon microbubbles. Detection of myocardial perfusion abnormalities during both exercise and pharmacologic stress echocardiography appears to be feasible clinically with either intravenous injections or continuous infusions of microbubbles using intermittent harmonic imaging. Accelerated intermittent harmonic imaging allows one to rapidly acquire both myocardial perfusion and wall motion during exercise and dobutamine stress echocardiography. (ECHOCARDIOGRAPHY, Volume 17, January 2000) [source]

Thermodynamic consistent modelling of defects and microstructures in ferroelectrics

GAMM - MITTEILUNGEN, Issue 2 2008
Ralf Müller
Abstract The paper describes the main phenomena associated with fatigue in ferroelectricmaterials due to defects and microstructural effects. An analysis the modelling on different length scales is presented. Starting from a thermodynamic analysis of the macroscopic material behavior other microscopic aspects are addressed. The introduction of an orientation distribution function allows for a computationally efficient extension of a single crystal model to realistic 3D structures. Additionally, the thermodynamic treatment of defects and domain wall motion is discussed to provide a better understanding of various micro-mechanisms. It is explained by the concept of configurational/driving forces, how defects influence each other and how the mobility of domain walls is reduced in the presence of defects. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Heat and fluid flow characteristics inside differentially heated square enclosures with single and multiple sliding walls

HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 7 2009
E.M. Wahba
Abstract Fluid flow and heat transfer characteristics of differentially heated lid driven cavities are numerically modeled and analyzed in the present study. One-, two-, and four-sided lid driven cavity configurations are considered with the vertical walls being maintained at different temperatures and the horizontal walls being thermally insulated. Eight different cavity configurations are considered depending on the direction of wall motion. The Prandtl number Pr is taken to be 0.7, the Grashof number is taken to be 104, while two values for the Richardson number Ri are considered, 0.1 and 10. It is found that both the Richardson number and the cavity configuration affect the heat and fluid flow characteristics in the cavity. It is concluded that for Ri=0.1, a four-sided driven cavity configuration with all walls rotating in the same direction would triple the value of the average Nusselt number at the cold wall when compared to a one-sided driven cavity configuration. However, for Ri=10, the cavity configuration has minimal effect and all eight cases result in an average Nusselt number value at the cold wall ranging between 1.3 and 1.9. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/htj.20264 [source]

Subcoercive Cyclic Electrical Loading of Lead Zirconate Titanate Ceramics II: Time-Resolved X-Ray Diffraction

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2009
Abhijit Pramanick
Structural changes such as non-180° domain wall motion and lattice strains in Pb(Zr,Ti)O3 ceramics are measured during the application of subcoercive cyclic electric fields using time-resolved high-energy X-ray diffraction with a stroboscopic data collection technique. The contributions to the electric-field-induced strains from non-180° domain wall motion and lattice distortions are determined as a function of material composition and type of dopant. For the different compositions studied, the largest strains due to non-180° domain wall motion are measured for La-doped tetragonal ceramics with a composition close to the morphotropic phase boundary. It is further observed that strain contributions from both non-180° domain wall motion and lattice distortions can be nonlinear with respect to the applied electric field. The correlation between the electric-field-induced structural changes and the macroscopic piezoelectric properties is discussed. [source]

Low antroduodenal pressure gradients are responsible for gastric emptying of a low-caloric liquid meal in humans

NEUROGASTROENTEROLOGY & MOTILITY, Issue 1 2002
T. HAUSKEN
The motor mechanisms responsible for transpyloric flow of gastric contents are still poorly understood. The aim of our study was to investigate the relationship between luminal pressures and gastric wall motion and between gastroduodenal pressure gradients and pressure waves, and ante- and retro-grade transpyloric flow. In eight healthy volunteers, intraluminal pressures were recorded from the antrum and proximal duodenum. Transpyloric flow was monitored simultaneously using duplex ultrasonography, before, during and after ingestion of 300 mL meat soup. Transpyloric emptying occurred as sequences of alternating periods of emptying,reflux,emptying. Approximately one-third of the sequences were not associated with peristalsis. The antroduodenal pressure gradients were significantly lower during nonperistaltic-related emptying than during peristaltic-related emptying (0.15 (0,0.3) kPa, and 1.7 (0.2,2.0) kPa, respectively [mean ± (range)], P < 0.005). The duration of emptying episodes not associated with peristalsis were significantly longer than those associated with peristalsis at (6.5 (3,8.7) s and 4.4 (2,6) s, respectively, P=0.059). Manometry detected only 56% of the antral contractions seen on ultrasound. We concluded that gastric emptying of a low-calorie liquid meal occurs both during peristaltic and nonperistaltic antral activity. In spite of lower antroduodenal pressure gradients, the emptying episodes were longer for nonperistaltic emptying, which is likely to be caused by low pyloric resistance. Considerable flow seems to occur without peristalsis during gastric emptying of a low-calorie, liquid meal in humans. [source]

Exercise- or dipyridamole-loaded QGS is useful to evaluate myocardial ischemia and viability in the patients with a history of Kawasaki disease

PEDIATRICS INTERNATIONAL, Issue 5 2005
Yuichi Ishikawa
AbstractBackground:,Evaluation of myocardial ischemia and viability is very important for the management of patients with a history of Kawasaki disease (KD). 99mTc-tetrofosmin myocardial perfusion scintigraphy combined with quantitative gated single photon computed emission tomography (QGS) gives us information, not only about perfusion, but also the percentage change in left ventricular wall thickness (%WT) and relative changes in left ventricular wall motion (LVM). Methods:,The subjects were 27 patients with a history of KD followed as outpatients at the National Cardiovascular Center, Osaka, Japan. Exercise-loaded QGS was performed on 21 patients, and dipyridamole- loaded QGS was performed in six patients younger than 7 years old. Results:,Perfusion defects (PD) were observed in 12 patients. Of the 12 patients, four with old myocardial infarction (OMI) had decreased %WT. All patients with OMI showed a decrease in %WT in the areas where PD was seen on the image. The other eight patients without OMI showed no decrease in %WT. In non-infarcted cases, the %WT was normal in the PD-positive area. Conclusions:,It is possible to evaluate myocardial ischemia and viability in KD patients by comparing PD on the image with %WT determined by QGS using exercise or drug-loaded myocardial scintigraphy alone. [source]

Percolated perpendicular medium of FePt-MgO/MgO bilayer films for ultra-high magnetic recording

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2007
An-Cheng Sun
Abstract Percolated perpendicular (FePt)100,x -(MgO)x thin films with x = 0,10.07 vol.% were fabricated on glass substrate with MgO(200)underlayer. When the substrate temperature was 580 oC, a significant enhancement in coercivity was observed at 1.23 vol.% of MgO, which was due to the precipitation of MgO in FePt film causing the hindrance in domain wall motion. As the amount of MgO was increased above 1.23 vol.%, the percolated perpendicular structure began to transform into granular perpendicular structure. Meanwhile, the MgO was found to segregate along grain boundaries of FePt grains, leading to the reduction of FePt grain size. As a result the coercivity and ordering parameter became smaller. In this study the percolated perpendicular medium using FePt film with doping adequate amount of MgO has shown possibility to be an efficient method to increase recording density if the film processing conditions are optimized further. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Ferroelastic phase transitions: structure and microstructure

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 1 2005
Ekhard K. H. Salje
Landau-type theories describe the observed behaviour of phase transitions in ferroelastic and co-elastic minerals and materials with a high degree of accuracy. In this review, the derivation of the Landau potential G = ½A,S [coth(,S/T) , coth(,S/TC)]Q2 + ¼BQ4 + , is derived as a solution of the general ,4 model. The coupling between the order parameter and spontaneous strain of a phase transition brings the behaviour of many phase transitions to the mean-field limit, even when the atomistic mechanism of the transition is spin-like. Strain coupling is also a common mechanism for the coupling between multiple order parameters in a single system. As well as changes on the crystal structure scale, phase transitions modify the microstructure of materials, leading to anomalous mesoscopic features at domain boundaries. The mesostructure of a domain wall is studied experimentally using X-ray diffraction, and interpreted theoretically using Ginzburg,Landau theory. One important consequence of twin mesostructures is their modified transport properties relative to the bulk. Domain wall motion also provides a mechanism for superelastic behaviour in ferroelastics. At surfaces, the relaxations that occur can be described in terms of order parameters and Landau theory. This leads to an exponential profile of surface relaxations. This in turn leads to an exponential interaction energy between surfaces, which can, if large enough, destabilize symmetrical morphologies in favour of a platelet morphology. Surface relaxations may also affect the behaviour of twin walls as they intersect surfaces, since the surface relaxation may lead to an incompatibility of the two domains at the surface, generating large strains at the relaxation. Landau theory may also be extended to describe the kinetics of phase transitions. Time-dependent Landau theory may be used to describe the kinetics of order,disorder phase transitions in which the order parameter is homogeneous. However, the time-dependent Landau theory equations also have microstructural solutions, explaining the formation of microstructures such as tweed. [source]

Segmental Differences of Impaired Diastolic Relaxation Following Cardiopulmonary Bypass Surgery in Children: A Tissue Doppler Study

ARTIFICIAL ORGANS, Issue 11 2009
Linda B. Pauliks
Abstract Impaired myocardial relaxation is an important aftereffect of cardiopulmonary bypass (CPB). Infants with their immature calcium metabolism may be particularly vulnerable. However, it has been difficult to quantitate diastolic dysfunction clinically. This study used tissue Doppler to measure regional diastolic myocardial velocities in 31 pediatric patients undergoing open heart surgery. Color tissue Doppler images were acquired in the operating room before and 8 and 24 h post CPB surgery. Early (E) and atrial (A) diastolic velocities were determined. Long axis motion was assessed from apical views near the mitral and tricuspid rings and radial wall motion from the parasternal view. The study included 31 children aged 3.6 ± 4.4 years (6 days to 16 years), with a mean weight of 14.7 ± 13.7 kg and body surface area of 0.59 ± 0.35 m2. Tissue Doppler analysis of regional wall motion revealed abnormal left ventricle (LV) and right ventricle (RV) diastolic relaxation in the early postoperative phase after CPB. Initially, all segments were significantly altered, but by 24 h, regional differences became apparent: LV radial wall motion was recovered, while longitudinal fibers in LV and RV appeared to be less resilient. RV myocardial mechanics were most abnormal. Tissue Doppler analysis may deepen our understanding of myocardial recovery and offers a sensitive tool to compare different cardioprotective strategies. [source]

Compliance properties of conduits used in vascular reconstruction,

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 11 2000
N. R. Tai
Background Compliance mismatch between native artery and prosthetic graft used for infrainguinal bypass is implicated in the aetiology of graft failure. The aim was to quantify the elastic properties of a new compliant poly(carbonate)polyurethane (CPU) vascular graft, and to compare the compliance properties of grafts made from CPU, expanded polytetrafluoroethylene (ePTFE), Dacron and human saphenous vein with that of human muscular artery. Methods A pulsatile flow phantom was used to perfuse vessel and prosthetic graft segments at physiological pulse pressure and flow. Intraluminal pressure was measured using a Millar Mikro-tip catheter transducer and vessel wall motion was determined with duplex ultrasonography using an echo-locked wall-tracking system. Diametrical compliance and a stiffness index were then calculated for each type of conduit over mean pressures ranging from 30 to 100 mmHg by 10-mmHg increments. Results The compliance values of CPU and artery (mean over the pressure range) were similar (mean(s.d.) 8·1(0·4) and 8·0(5·9) per cent per mmHg × 10,2 respectively), although the elastic behaviour of artery was anisotropic unlike CPU, which was isotropic. Dacron and ePTFE grafts had lower compliance values (1·8(1·2) and 1·2(0·3) per cent per mmHg × 10,2 respectively, averaged over the pressure range). In both these cases, compliance and stiffness differed significantly from that of artery over a mean pressure range of 30,90 mmHg. Human saphenous vein exhibited anisotropic behaviour and, although compliant at low pressure (30 mmHg), was markedly incompliant at higher pressures. Conclusion Compliant polyurethane grafts offer a greater degree of compliance match than either ePTFE or Dacron. © 2000 British Journal of Surgery Society Ltd [source]

Transient global left ventricular dysfunction in a localized myocardial infarction related to occlusion of the distal left anterior descending artery

CLINICAL CARDIOLOGY, Issue 9 2006
Seong Bo Yoon M.D.
Abstract In some patients with acute myocardial infarction (MI), wall motion in the noninfarcted area declines globally despite localized myocardial damage. In most, an infarct-related lesion is the proximal part of the left anterior descending artery (LAD). Previous studies have reported that hypo-kinesis of remote myocardium may be related to multivessel disease, impaired coronary flow, or coronary flow reserve in nonculprit arteries. This report describes the case of a 53-year-old man who presented with severe global left ventricular (LV) dysfunction after an acute MI associated with distal LAD occlusion. Follow-up echocardiographic examination revealed nearly normalized LV function 5 days after the episode. We discuss a plausible mechanism of dysfunction of noninfarcted myocardium. [source]

Postsystolic thickening detected by doppler myocardial imaging: A marker of viability or ischemia in patients with myocardial infarction

CLINICAL CARDIOLOGY, Issue 1 2004
Jae-Kwan Song M.D.
Abstract Background: Postsystolic thickening (PST) of ischemic myocardial segments has been reported to account for the characteristic heterogeneity or regional asynchrony of myocardial wall motion during acute ischemia. Hypothesis: Postsystolic thickening detected by Doppler myocardial imaging (DMI) could be a useful clinical index of myocardial viability or peri-infarction viability in patients with myocardial infarction (MI). Methods: Doppler myocardial imaging was recorded at each stage of a standard dobutamine stress echocardiogram (DSE) in 20 patients (16 male, 60 ± 13 years) with an MI in the territory of the left anterior descending artery. Myocardial velocity data were measured in the interventricular septum and apical inferior segment of the MI territory. Postsystolic thickening was identified if the absolute velocity of PST was higher than peak systolic velocity in the presence of either a resting PST > 2.0 cm/s or if PST doubled at low-dose dobutamine infusion. Results: Doppler myocardial imaging data could be analyzed in 38 ischemic segments (95%), and PST was observed in 21 segments (55%), including 3 segments showing PST only at low-dose dobutamine infusion. There was no significant difference of baseline wall motion score index (2.1 ± 0.3 vs. 2.1 ± 0.6, p = 0.77) orpeak systolic velocity (1.1 ± 1.1 vs. 1.9 ± 2.0 cm/s, p = 0.05) between segments with and without PST. Peri-infarction ischemia or viability during DSE was more frequently observed in segments with PST than in those without (86 vs. 24%, p < 0.05). The sensitivity and specificity of P ST for prediction of peri-infarction viability or ischemia was 82 and 81%, respectively. Conclusions: Postsystolic thickening in the infarct territory detected by DMI is closely related with peri-infarction ischemia or viability at DSE. [source]

Postoperative troponin I values: Insult or injury?

CLINICAL CARDIOLOGY, Issue 10 2000
Keith A. Horvath M.D.
Abstract Background: Troponin I (TnI) is increasingly employed as a highly specific marker of acute myocardial ischemia. The value of this marker after cardiac surgery is unclear. Hypothesis: The purpose of this study was to measure serum TnI levels prospectively at 1, 6, and 72 h after elective cardiac operations. In addition, TnI levels were measured from the shed mediastinal blood at 1 and 6 h postoperatively. Serum values were correlated with cross clamp time, type of operation, incidence of perioperative myocardial infarction, as assessed by postoperative electrocardiograms (ECG) and regional wall motion, as documented by intraoperative transesophageal echocardiography (TEE). Methods: Sixty patients underwent the following types of surgery: coronary artery bypass graft (CABG) (n = 45), valve repair/replacement (n = 10), and combination valve and coronary surgery (n = 5). Myocardial protection consisted of moderate systemic hypothermia (30,32°C), cold blood cardioplegia, and topical cooling for all patients. Results: Of 60 patients, 57 (95%) had elevated TnI levels, consistent with myocardial injury, 1 h postoperatively. This incidence increased to 98% (59/60) at 6 h postoperatively. There was a positive correlation between the length of cross clamp time and initial postoperative serum TnI (r = 0.70). There was no difference in the serum TnI values whether or not surgery was for ischemic heart disease (CABG or CABG + valve versus valve). There were no postoperative myocardial infarctions as assessed by serial ECGs. There was no evidence of diminished regional wall motion by TEE. Levels of TnI in the mediastinal shed blood were greater than assay in 58% (35/60) of the patients at 1 h and in 88% (53/60) at 6 h postoperatively. Patients who received an auto-transfusion of mediastinal shed blood (n = 22) had on average a 10-fold postoperative increase in serum TnI levels between 1 and 6 h. Patients who did not receive autotransfusion average less than doubled their TnI levels over the same interval. At 72 h, TnI levels were below the initial postoperative levels but still indicative of myocardial injury. Conclusion: Postoperative TnI levels are elevated after all types of cardiac surgery. There is a strong correlation between intraoperative ischemic time and postoperative TnI level. Further elevation of TnI is significantly enhanced by reinfusion of mediastinal shed blood. Despite these postoperative increases in TnI, there was no evidence of myocardial infarction by ECG or TEE. The postoperative TnI value is even less meaningful after autotransfusion of shed mediastinal blood. [source]

Comparison of echocardiography and electron beam tomography in differentiating the etiology of heart failure

CLINICAL CARDIOLOGY, Issue 6 2000
Thuy Le M.D.
Abstract Background: The clinical manifestations in patients with ischemic cardiomyopathy are often indistinguishable from those in patients with primary dilated cardiomyopathy (DCM). Clinicians often base work-up of patients with heart failure on echocardiographic wall motion abnormalities; however misclassification can lead to unnecessary coronary angiography. Hypothesis: The study was undertaken to evaluate the diagnostic ability of echocardiography and electron beam tomography (EBT) to differentiate between ischemic and nonischemic cardiomyopathy. Methods: The accuracy of EBT and echocardiography was compared in 111 patients undergoing coronary angiography for the evaluation of heart failure. The presence of coronary calcification (CC) by EBT or segmental wall motion abnormalities by echocardiography was used as evidence of coronary-induced cardiomyopathy. Results: Of 63 patients, 61 (97%) with obstructive coronary artery disease had CC by EBT. This sensitivity was significantly higher compared with 43 of 63 patients (68%) with segmental wall motion abnormalities by echocardiography (p < 0.001). Of 48 patients without obstructive coronary artery disease by angiography, 39 (81%) had no CC by EBT and 35 (73%) had no segmental wall motion (global hypokinesis) by echocardiography (p = 0.33). The overall accuracy of EBT to differentiate ischemic from nonischemic cardiomyopathy was 90%, significantly higher than echocardiography (70%, p < 0.001). Conclusion: This double-blind study demonstrates that the presence of CC by EBT is superior to that of segmental wall motion abnormalities by echocardiography to distinguish ischemic from nonischemic cardiomyopathy. This modality may prove to be an important diagnostic tool when the etiology of the cardiomyopathy is not clinically evident. [source]

Diagnostic performance of cardiac magnetic resonance imaging in coronary artery disease

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 2 2010
Jussi P. Pärkkä
Summary Background:, Cardiac magnetic resonance imaging (CMR) is a promising method for detecting coronary artery disease (CAD). The first reports of new diagnostic techniques indicated generally unrealistic diagnostic performance relying on retrospectively observed cut-off values of quantitative parameters. Although visual analysis of CMR is the most applicable method for clinical work, its diagnostic performance is not fully elucidated for study components such as wall motion, perfusion and late enhancement in patients with different severity of CAD. Methods:, A total of 30 subjects including 20 patients with CAD and 10 healthy volunteers were selected for the study. Of the patients, ten had stable CAD, five confirmed myocardial infarction (MI) without Q-waves in electrocardiogram (ECG) and five confirmed MI with Q-waves in ECG. All patients underwent coronary angiography and CMR for evaluating resting wall motion, rest and stress perfusion and late enhancement. Results:, Combining the data from the three CMR techniques, 12 out of 20 patients were correctly identified as having CAD, and all controls were found to be healthy. Sensitivity, specificity, accuracy, positive and negative predictive values were 60·0%, 100·0%, 73·0%, 100·0% and 55·6%, respectively. Of the CMR components, resting wall motion and late enhancement gave the most diagnostic yield. Conclusions:, We conclude that evaluation of CAD is feasible in patients with different severity of CAD using visually analysed CMR, especially when available CMR methodologies are combined together. [source]

Validation of a new automated method for analysis of gated-SPECT images

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 3 2006
Milan Lomsky
Summary We recently presented a new method for quantification of CArdiac FUnction , denoted CAFU , as the first step in the development of an automated method for integrated interpretation of gated myocardial perfusion single photon emission computed tomography (SPECT) images. The aim of this study was to validate CAFU in the assessment of global and regional function of the left ventricle. Quantitative gated-SPECT (QGS), the most widely used software package for quantification of gated-SPECT images, was used as reference method for the measurements of ejection fraction (EF) and ventricular volumes, and visual analysis by an experienced physician was used as reference method for the measurements of regional wall motion and thickening. Two different groups of consecutive patients referred for myocardial perfusion scintigraphy were studied. Global function was evaluated in 316 patients and regional function in 49 other patients. The studies were performed using a 2-day stress/rest 99 m-Tc-sestamibi protocol. A good correlation was found between EF values from QGS and CAFU (EF CAFU = 0·84 EF QGS + 13, r = 0·94), but CAFU values were on average 4 EF points higher than QGS values. With CAFU the segments with normal thickening according to the physician showed significantly higher thickening values (in all parts of the myocardium) compared to the segments classified as having abnormal thickening. In conclusion, this study demonstrates that CAFU can be used to quantify global and regional function in gated-SPECT images. This is an important step in our development of an automated method for integrated interpretation of gated-SPECT myocardial perfusion scintigraphy studies. [source]