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La tilapia es un pez dulceacuícola originario del África que posee muchas características que la convierten en un excelente pez para acuicultura, pero también es considerada como una de las especies exóticas invasoras más peligrosas del mundo debido a su adaptabilidad y potencial reproductivo. En este ensayo se analiza el dilema entre las bondades de estos peces como alternativa para contribuir con la seguridad agroalimentaria y la amenaza que representa para la biodiversidad acuática de Ecuador. La ausencia de información oficial hace necesario investigar el efecto de las invasiones por tilapia en los ríos, lagunas y esteros colonizados por esta especie. El nivel de acción para prevenir, erradicar o controlar la tilapia en Ecuador ha sido muy limitado y por lo tanto se impone la necesidad de establecer estrategias para evitar su propagación hacia áreas aún no invadidas. Aunque el gobierno de Ecuador posee regulaciones que restringen la introducción de especies exóticas, la realidad es que, en el caso de la tilapia, lejos de establecer controles adecuados, el cultivo de estos peces es impulsado sin mayores objeciones. Se discute la posibilidad de adoptar estrategias de control biológico para erradicar y/o mitigar las consecuencias de la invasión por tilapias en el país y la necesidad de fomentar campañas educativas para crear un nuevo comportamiento ambiental, conciencia y responsabilidad en la sociedad.

Presents a brief account of the beginnings of the Universidad de Oriente, higher education institution seated in the eastern territory of Venezuela; as well as also related to attempts to establish a “editorial policy” in the different campuses university, periodical publications of scientific character. In describing the path of SABER periodical publication, multidisciplinary, financed and edited by the Research Council , presents a sequence of events that have marked both their presence and their contribution to the university community. Finally we suggest a number of actions to continue the important work of SABER as scientific journal of the Universidad de Oriente.

From the moment small groups of individuals are introduced and become incorporated into a receptor environment, in addition to their obvious advantageous characteristics as potential invaders, complex interactions between the environment and genetic and epigenetic mechanisms arise to either thwart or foster the invasion. To understand invasions, different kinds of mechanisms that would allow the introduced organisms to become invasive in their new environments must be analyzed: enemy release, mutualist release, allelopathy, Darwin’s naturalization hypothesis, breakdown of biotic regulation, empty niches, propagule pressure, genetic variation increase (by means of hybridization, genome and gene duplication, endosymbiosis, transposition, somatic mutations, mitotic recombinations, small regulatory RNAs), purge, adaptive mutations, phenotypic plasticity, and epigenetic changes. These processes are critical to explaining the success of some alien species in new environments.

Background: The trial "Stress Echo (SE) 2020" evaluates novel applications of SE beyond coronary artery disease. The aim of the study was control quality and harmonize reading criteria.Methods: One reader from 78 centers of the SE 2020 network asked for credentials to read a set of 20 SE videoclips selected by the core lab. All aspiring centers met the pre-requisite of high-volume and the years of experience in SE ranged from 5 to 31 years (mean value 18 years). The diagnostic gold standard was a reading by the core lab. The a priori determined pass threshold was 18/20 (>= 90%).Results: Of the initial 78 who started, 57 completed the first attempt: individual readers' score on first attempt ranged from 07/20 to 20/20 (accuracy from 35% to 100%, mean 78.7 +/- 13%) and 44 readers passed it. There was a very poor correlation between years of experience and the reader's score on first attempt (r = -0.161, p = 0.231). Of the 13 readers who failed the first attempt, 12 took it again after the web-based session and their accuracy improved (74% vs. 96%, p < 0.001). The kappa inter-observer agreement before and after web-based training was 0.59 on first attempt and rose to 0.91 on the last attempt.Conclusions: In SE reading, the volume of activity or years of experience is not synonymous with diagnostic quality. Qualitative analysis and operator-dependence can become a limiting weakness in clinical practice, in the absence of strict pathways of learning, credentialing and audit. (C) 2017 Elsevier B.V. All rights reserved.

An increasing number of patients are implanted with continuous-flow left ventricular assist devices (LVAD) for the treatment of severe congestive heart failure. In parallel with this growing experience has been an increase in knowledge of how these devices alter cardiac physiology and the important implications this has for cardiac function. Echocardiography offers the ability to provide serial noninvasive evaluation before and after LVAD implantation to document these changes, guide management decisions, and identify LVAD dysfunction. The authors detail a comprehensive assessment of LVAD function by transthoracic echocardiography.

Continuing Medical Education Course for "American Society of Echocardiography Consensus Statement on the Clinical Applications of Ultrasonic Contrast Agents in Echocardiography" Accreditation Statement The American Society of Echocardiography (ASE) is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The ASE designates this educational activity for a maximum of 1 AMA PRA Category 1 Credit .™ Physicians should only claim credit commensurate with the extent of their participation in the activity. The American Registry of Diagnostic Medical Sonographers and Cardiovascular Credentialing International recognize the ASE's certificates and have agreed to honor the credit hours toward their registry requirements for sonographers. The ASE is committed to resolving all conflict-of-interest issues, and its mandate is to retain only those speakers with financial interests that can be reconciled with the goals and educational integrity of the educational program. Disclosure of faculty and commercial support sponsor relationships, if any, have been indicated. Target Audience This activity is designed for all cardiovascular physicians, cardiac sonographers, and nurses with a primary interest and knowledge base in the field of echocardiography; in addition, residents, researchers, clinicians, sonographers, and other medical professionals having a specific interest in contrast echocardiography may be included. Objectives Upon completing this activity, participants will be able to: 1. Demonstrate an increased knowledge of the applications for contrast echocardiography and their impact on cardiac diagnosis. 2. Differentiate the available ultrasound contrast agents and ultrasound equipment imaging features to optimize their use. 3. Recognize the indications, benefits, and safety of ultrasound contrast agents, acknowledging the recent labeling changes by the US Food and Drug Administration (FDA) regarding contrast agent use and safety information. 4. Identify specific patient populations that represent potential candidates for the use of contrast agents, to enable cost-effective clinical diagnosis. 5. Incorporate effective teamwork strategies for the implementation of contrast agents in the echocardiography laboratory and establish guidelines for contrast use. 6. Use contrast enhancement for endocardial border delineation and left ventricular opacification in rest and stress echocardiography and unique patient care environments in which echocardiographic image acquisition is frequently challenging, including intensive care units (ICUs) and emergency departments. 7. Effectively use contrast echocardiography for the diagnosis of intracardiac and extracardiac abnormalities, including the identification of complications of acute myocardial infarction. 8. Assess the common pitfalls in contrast imaging and use stepwise, guideline-based contrast equipment setup and contrast agent administration techniques to optimize image acquisition. Author Disclosures Sharon L. Mulvagh: research grant, Lantheus Medical Imaging, GE Healthcare, and Astellas Pharma; consultant/advisory, Acusphere, Point Biomedical. Mani A. Vannan: research grant, other research support, speaker bureau/honoraria, and consultant/advisory board, Lantheus Medical Imaging. Harald Becher: research grant, Philips, Sonosite, and Toshiba; speaker bureau/honoraria, Lantheus Medical Imaging; consultant/advisory board, Point Biomedical, Bracco, Acusphere, ICON, Lantheus Medical Imaging. S. Michelle Bierig: research grant, Lantheus Medical Imaging, Amersham. Peter N. Burns: consultant/advisory board, Philips Ultrasound, Lantheus Medical Imaging. Dalane W. Kitzman: research grant, Lantheus Medical Imaging, IMCOR, Sonus; speakers bureau, Lantheus Medical Imaging; consultant/advisory board, Lantheus Medical Imaging, Acusphere. Itzhak Kronzon: research grant, GE Healthcare. Arthur J. Labovitz: consultant/advisory board, ICON Medical. Roberto M. Lang: research grant, Acusphere, Point Biomedical; speaker bureau, Lantheus Medical Imaging; consultant/advisory board, Lantheus Medical Imaging. Julio E. Perez: consultant/advisory board, Biomedical Systems. Thomas R. Porter: research grant, Lantheus Medical Imaging; consultant/advisory board, Acusphere, ImaRx. Judy Rosenbloom: paid consultant with ultrasound equipment manufacturers. Kevin Wei: research grant, Lantheus Medical Imaging, Philips Ultrasound; consultant/advisory board, Acusphere. The following stated no disclosures: Harry Rakowski, Sahar S. Abdelmoneim, Ramon Castello, Patrick D. Coon, Mary E. Hagen, James G. Jollis, Thomas R. Kimball, Joseph Mathew, Stuart Moir, Sherif F. Nagueh, Alan S. Pearlman, G. Monet Strachan, Srihari Thanigaraj, Anna Woo, Eric H. C. Yu, and William A. Zoghbi. Conflicts of Interest: The authors have no conflicts of interest to disclose except as noted above. Estimated Time to Complete This Activity: 1 hour

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:43:34Z No. of bitstreams: 1 S1679-62252008000100012.pdf: 1647051 bytes, checksum: b3947a66df7c24b899c1f2c920c79b21 (MD5) Made available in DSpace on 2013-08-22T18:43:34Z (GMT). No. of bitstreams: 1 S1679-62252008000100012.pdf: 1647051 bytes, checksum: b3947a66df7c24b899c1f2c920c79b21 (MD5) Previous issue date: 2008-03-01 Made available in DSpace on 2013-09-30T19:31:19Z (GMT). No. of bitstreams: 2 S1679-62252008000100012.pdf: 1647051 bytes, checksum: b3947a66df7c24b899c1f2c920c79b21 (MD5) S1679-62252008000100012.pdf.txt: 29933 bytes, checksum: 94a5e7172d23fecc7d7180459b17e04f (MD5) Previous issue date: 2008-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:51:35Z No. of bitstreams: 2 S1679-62252008000100012.pdf: 1647051 bytes, checksum: b3947a66df7c24b899c1f2c920c79b21 (MD5) S1679-62252008000100012.pdf.txt: 29933 bytes, checksum: 94a5e7172d23fecc7d7180459b17e04f (MD5) Made available in DSpace on 2014-05-20T13:51:35Z (GMT). No. of bitstreams: 2 S1679-62252008000100012.pdf: 1647051 bytes, checksum: b3947a66df7c24b899c1f2c920c79b21 (MD5) S1679-62252008000100012.pdf.txt: 29933 bytes, checksum: 94a5e7172d23fecc7d7180459b17e04f (MD5) Previous issue date: 2008-03-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) No presente estudo três espécies de Lutjaninae, Lutjanus analis, L. griseus e L. synagris foram analisadas através da coloração convencional com Giemsa, banda C e coloração com nitrato de prata para identificar as Regiões Organizadoras de Nucléolo (NORs) ativas. Hibridação fluorescente in situ (FISH) foi também aplicada para estabelecimento do número e localização dos agrupamentos de genes ribossômicos (18S e 5S rRNA). A contagem de células metafásicas revelou um número diplóide modal de 48 cromossomos acrocêntricos em L. analis e L. griseus. Dois citótipos foram observados em L. synagris: citótipo I com 2n=48 cromossomos acrocêntricos, encontrado em 19 espécimes, e citótipo II com 46 cromossomos acrocêntricos e um grande metacêntrico, encontrado em dois espécimes. O grande metacêntrico, que possivelmente se originou por um rearranjo Robertsoniano, não está relacionado com o sexo. Nas três espécies a heterocromatina constitutiva está localizada nas regiões centroméricas de todos os cromossomos. NORs foram detectadas no braço curto de um único par cromossômico, número 24 em L. analis e número 6 em ambos os citótipos de L. synagris. em L. griseus, um polimorfismo de número de NORs foi observado, após coloração com prata e por FISH, as fêmeas apresentaram um máximo de três NORs e os machos um máximo de seis NORs. em todas as espécies os genes ribossômicos 5S foram encontrados em um único par cromossômico. Os dados obtidos, somados aos demais previamente publicados para cinco outras espécies de Lutjanidae, mostram que na família há uma homogeneidade cromossômica, porém também são encontrados cariótipos derivados, originados por rearranjos Robertsonianos, assim como pela ocorrência de sítios múltiplos e variados de NORs. In the present study, three species of Lutjaninae, Lutjanus analis, L. griseus and L. synagris, were analyzed by conventional Giemsa staining, C-banding and silver staining, to reveal active Nucleolus Organizer Regions (NORs). Fluorescent in situ hybridization (FISH) was also applied to establish the number and location of the ribosomal gene clusters (18S and 5S rRNA genes). Counts of diploid metaphasic cells revealed a diploid modal chromosome complement composed of 48 acrocentric chromosomes in both L. analis and L. griseus. Two cytotypes were observed in L. synagris: cytotype I, with 2n=48 acrocentric chromosomes, found in 19 specimens, and cytotype II, with 46 acrocentric chromosomes and one large metacentric, found in two specimens. The large metacentric, which possibly originated from a Robertsonian rearrangement, was not found to be sex-related. In the three species, constitutive heterochromatin is located in the centromeres of all chromosomes. NORs were detected on the short arms of a single chromosome pair, number 24 in L. analis and number 6 in both cytotypes of L. synagris. In L. griseus, a polymorphism of the NORs number was detected, by both Ag-staining and FISH, as females show a maximum of three NORs, and males a maximum of six NORs. In all species, minor ribosomal genes were found located on a single chromosome pair. The obtained data, along with those previously reported for other five Lutjanidae species, show that a general chromosome homogeneity occurs within the family, but that derived karyotypes based on Robertsonian rearrangements as well as multiple and variable NORs sites can also be found. Universidad de Oriente Escuela de Ciencias Aplicadas del Mar Universidade Estadual Paulista Instituto de Biociências Departamento de Morfologia Universidad de Oriente Instituto Oceanográfico de Venezuela University of Rome Department of Human and Animal Biology Universidade Estadual Paulista Instituto de Biociências Departamento de Morfologia

Objective The purpose of this study was to determine whether resting myocardial deformation and rotation may be altered in diabetic patients with significant epicardial coronary artery disease (CAD) with normal left ventricular ejection fraction. Design A prospective observational study. Setting Diagnosis of epicardial CAD in patients with diabetes. Patients and Methods Eighty-four patients with diabetes suspected of epicardial CAD scheduled for cardiac catheterization had a resting echocardiogram performed prior to their procedure. Echocardiographic measurements were compared between patients with and without significant epicardial CAD as determined by cardiac catheterization. Main Outcome Measures Measurement of longitudinal strain, strain rate, apical rotation, and rotation rate, using speckle tracking echocardiography. Results Eighty-four patients were studied, 39 (46.4%) of whom had significant epicardial CAD. Global peak systolic apical rotation was significantly increased (14.9 ± 5.1 vs. 11.0 ± 4.8 degrees, P < 0.001) in patients with epicardial CAD along with faster peak systolic apical rotation rate (90.4 ± 29 vs. 68.1 ± 22.2 degrees/sec, P < 0.001). These findings were further confirmed through multivariate logistic regression analysis (global peak systolic apical rotation OR = 1.17, P = 0.004 and peak systolic apical rotation rate OR = 1.05, P < 0.001). Conclusions Patients with diabetes with significant epicardial CAD and normal LVEF exhibit an increase in peak systolic apical counterclockwise rotation and rotation rate detected by echocardiography, suggesting that significant epicardial CAD and its associated myocardial effects in patients with diabetes may be detected noninvasively at rest.

Crohn's disease results in a hypercoagulable state increasing the risk of venous or arterial thromboembolism. Cardiac involvement has not been routinely identified. Two cases are presented to illustrate that patients with Crohn's disease may represent an exception to the rule that left ventricular apical thrombus should be associated with an underlying wall motion abnormality and reduction in left ventricular ejection fraction.

One of the most relevant topics in the biology of invasion concerns the genetic changes that occur subsequent to a species invasion, an issue of particular focus among conservation biologists. Colonizing a novel environment presents a genetic challenge to invading species because such species surely have not experienced the selective pressures presented by the environment. Here we ask, by what mechanisms and

This paper reports the results of cytogenetic analyses carried out on Porichthys plectrodon using conventional Giemsa staining, C-banding and silver staining techniques. A diploid chromosome count of 2n=44 was observed, consisting of 8 metacentric, 10 submetacentric, 6 subtelocentric and 20 acrocentric chromosomes. Differences in length made it possible to identify homologous chromosomes within the metacentric group. Constitutive heterochromatin was distributed as large pericentromeric blocks in pairs 1 and 2, while the rest of the chromosomes were marked in centromeric regions, some more conspicuously than others. One pair of small-sized acrocentric NOR-bearing chromosomes (21) was identified by the nucleolar regions located terminally on their short arms.

Conventional karyotype and nucleolar organizer regions (NORs) of C. macropomum x P. brachypomus hybrids and parental species are reported. A modal diploid number of 54 chromosomes and a fundamental number (NF) of 108 were found for C. macropomum, P. brachypomus and their hybrids. P. brachypomus shows a pair of silver stained chromosomes, while cells with three and four Ag-NOR bearing chromosomes were observed in C. macropomum. The hybrids consistently presented cells with a single metacentric Ag-NOR bearing chromosome and cells with three Ag-NOR bearing chromosomes. The FISH technique was employed to localize 18S rDNA in the chromosomes of the parentals and the hybrids. In P. brachypomus the FITC signals appeared in the SM pair as when stained with silver salts. In C. macropomum the signals were evidenced in six chromosomes. In the hybrids, as expected, the FITC dots were observed in four chromosomes. All the techniques employed in the present work represent good tools to identify the parentals a...

Existe una variedad de pruebas no invasivas a disposicion de los clinicos para ser utilizadas en la valoracion del enfermo con sospecha de cardiopatia isquemica, ya sea por presentar dolor toracico, por otros antecedentes clinicos o por una combinacion de estos. A pesar de que, en general, todas las pruebas contribuyen de forma variada a refinar (afirmar o rechazar) el diagnostico de un enfermo en particular, no hay duda de que existen diferencias importantes entre las diversas pruebas con respecto a su alcance y su certeza diagnostica en general, y mas aun en algunos grupos de enfermos en particular. Por esto, y por las obvias implicaciones economicas, el tema merece un repaso critico antes de utilizar, en el manejo clinico del enfermo, la informacion que se obtenga de estas pruebas. Esta revision no pretende abarcar todos los aspectos a favor y en contra de todas las pruebas no invasivas de la cardiopatia isquemica que estan disponibles en el momento, sino quiza poner en perspectiva la importancia de la valoracion clinica del enfermo a la luz de los resultados de las pruebas, para asi obtener una idea mas logica de su valor. A riesgo de pecar por exclusion, tecnicas excelentes como la resonancia magnetica no van a ser objeto de repaso en esta ocasion solo porque no han sido inlcuidas hasta ahora en metaanalisis para este proposito. El enfasis en el razonamiento o paradigma bayesiano y la discusion de ensayos recientes de metaanalisis al respecto ofrecen una perspectiva equilibrada sobre el uso y posible uso indebido de estas pruebas diagnosticas, con implicaciones clinicas y economicas. Palabras clave: Pruebas de esfuerzo. Imagenes en cardiologia. Paradigma bayesano.

Karyotypes of three species of toadfish (Amphichthys cryptocentrus, Batrachoides manglae and Thalassophryne maculosa), reported here for the first time revealed diploid complements of 46 chromosomes. Karyo-evolutionary trend of these species is discussed. Based on differences in arm number, we suggest that T. maculosa possesses the most evolved karyotype among the three species, hence it would be the more recent one, followed by B. manglae and A. cryptocentrus., No Disponible

OBJECTIVE—To assess the feasibility of measuring left atrial (LA) function with acoustic quantification (AQ) and then assess the effects of age and sex on LA reservoir, conduit, and booster pump function. PATIENTS AND SETTING—165 subjects without cardiovascular disease, 3-79 years old, were enrolled by six tertiary hospital centres. INTERVENTIONS—Continuous LA AQ area data were acquired and signal averaged to form composite waveforms which were analysed off-line. MAIN OUTCOME MEASURES—Parameters of LA performance according to age and sex. RESULTS—Signal averaged LA waveforms were sufficiently stable and detailed to allow automated analysis in all cases. An age related increase in LA area was noted. LA reservoir function did not vary with age or sex. All parameters of LA passive and active emptying revealed a significant age dependency. Overall, the passive emptying phase accounted for 66% of total LA emptying ranging from 76% in the youngest to 44% in the oldest decade. LA contraction accounted for 34% of atrial emptying in all subjects combined with the older subjects being more dependent on atrial booster pump function. When adjusted for atrial size, there were no sex related differences in LA function. CONCLUSIONS—LA reservoir, conduit, and booster pump function can be assessed with automated analysis of signal averaged LA area waveforms. As LA performance varies with age, establishment of normal values should enhance the evaluation of pathologic states in which LA function is important. Keywords: aging; atrium; echocardiography

Although myocardial ischemia impairs left ventricular (LV) relaxation before contractile function, regional LV diastolic dysfunction is difficult to evaluate by conventional echocardiography. Because beta-adrenergic stimulation enhances myocardial relaxation, we sought to characterize segmental LV diastolic function (by color kinesis) during dobutamine stress echocardiography and compare it with independently assessed segmental systolic function. We studied 22 patients with suspected coronary artery disease with color kinesis by acquiring digital images with endocardial motion display throughout diastole. Quantification of LV segmental diastolic peak filling rate (SPFR, normalized to segmental end-diastolic area/s) was obtained at rest, low-dose, and peak dobutamine infusion in myocardial segments visualized from the short-axis and/or apical 4-chamber views. In patients with resting normal LV systolic function and a dobutamine-induced hypercontractile response (group I, n = 13 patients; 102 segments), progressive increases in SPFR (p

Contrast echocardiography improves left ventricular (LV) endocardial border delineation by enhancement of the blood-tissue interface. In particular, the contrast appearing within the LV chamber exhibits characteristic flow patterns over the cardiac cycle, which may be related to the surrounding myocardial wall motion. To determine the relation between the LV intracavitary contrast flow pattern and surrounding wall motion, we reviewed the contrast-enhanced images of 348 consecutive patients studied at rest. We defined 2 different patterns of intracavitary contrast flow as visualized from apical views: a swift, vertical, and homogeneous flow towards the apex (pattern A), and a distinctly protracted, swirling, and heterogeneous flow (pattern B). Images recorded on videotapes were reviewed and the type of pattern (A or B) was determined within the initial 30 to 45 seconds of contrast appearance in the left ventricle. Contrast flow patterns interpreted by independent reviewer were then compared with the interpretation of the LV segmental and global function in each patient. Results demonstrate that 224 of 245 (91%) patients exhibiting pattern A had normal LV segmental function. Furthermore, all but 1 patient (102 of 103) with pattern B had > or =1 wall motion abnormality (p

To determine the influence of myocardial anisotropy in ultrasonic tissue characterization, we measured the time delay (and magnitude) of the cyclic variation of myocardial integrated backscatter from specific segments visualized in the 4 standard transthoracic echocardiographic views. The cyclic variation data in 10 myocardial regions were obtained from analyses of 2-dimensional integrated backscatter images from 23 healthy subjects. Resultant values (mean ± SD) for the time delay were as follows: parasternal long-axis view: 1.08 ± 0.17 (septum) and 1.00 ± 0.14 (posterior wall); parasternal short-axis view: 1.03 ± 0.16 (anterior septum), 1.03 ± 0.14 (posterior wall), 2.22 ± 0.71 (lateral wall), and 1.65 ± 0.66 (posterior septum); apical 4-chamber view: 1.08 ± 0.31 (septum) and 2.20 ± 0.79 (lateral wall); and apical 2-chamber view: 1.68 ± 0.62 (inferior wall) and 2.04 ± 0.72 (anterior wall). Hence, results of this study indicate that myocardial ultrasonic characterization that uses the cyclic variation is influenced by the echocardiographic view and the specific segment of the left ventricle. (J Am Soc Echocardiogr 2000;13:9-17.)

Transthoracic echocardiography is the most widely used diagnostic test for left ventricular (LV) thrombus, which must be distinguished from other intraventricular structures and image artifacts. To determine whether second-generation intravenous echocardiographic contrast agents provide better delineation of LV thrombus, we reviewed the results of 2-dimensional echocardiographic studies that were performed in 409 patients over a 1-year period to detect LV thrombus. Studies of 190 (46%) patients were interpreted as nondiagnostic for this purpose, of which 48 patients underwent an additional study after intravenous injection of 0.5 to 2 mL of human albumin microspheres within 1 to 4 days. In 43 (90%) of these 48 patients the contrast-enhanced study was definitive and diagnostic for either the presence or absence of an LV thrombus (P.0001). Of the initial total of 409 patients, 81 had been studied at the bedside in intensive care units. The bedside studies were nondiagnostic for LV thrombus in 51 (63%) of these 81 patients. Of these 51 patients, 14 underwent additional imaging with contrast enhancement, and the contrast-enhanced images became diagnostic (P =. 004) in 11 (79%) of them. Thus intravenous contrast image enhancement improves the diagnostic yield of echocardiography in patients in whom initial images are nondiagnostic for LV thrombus.

Objectives To determine whether dobutamine stimulation in patients with Chagas’ disease may uncover abnormal contractile responses as seen in ischemic myocardium. Background Segmental left ventricular (LV) dysfunction in the absence of coronary atherosclerosis is frequently seen in patients with chronic Chagas’ heart disease. Myocardial ischemia and coronary microcirculation abnormalities have been found in animal models and in humans with Chagas’ disease. In addition, chagasic sera may contain autoantibodies against human beta-adrenergic receptors. Methods Two groups of patients with Chagas’ disease were studied by echocardiography: group 1 (n = 12) without and group 2 (n = 14) with LV segmental wall motion abnormalities (mostly apical aneurysm). Ten normal subjects served as control subjects. We performed qualitative assessment of wall motion and quantitative evaluation of LV cavity under baseline conditions and after dobutamine stimulation. Results Patients with Chagas’ disease exhibited a blunted inotropic and chronotropic response to dobutamine stimulation. After dobutamine, fractional area change in Chagas’ group 1 (54.7 ± 6.6%; SD) and in group 2 (35.1 ± 12.1%) were significantly lower than control group (66.7 ± 2.5%; p Conclusions Thus, dobutamine stimulation unmasks a chronotropic incompetence and a blunted myocardial contractile response in chagasic patients, even in those with no overt manifestation of heart disease.

Identificar de forma no invasiva la estructura normal y las modificaciones patologicas que se producen en el tejido miocardico permitiendonos determinar su etiologia y grado de severidad es uno de los objetivos principales en cardiologia. La caracterizacion tisular por ultrasonidos intenta definir el estado fisico del corazon mediante el analisis de los cambios patologicos que modifican las propiedades fisicas del tejido cardiaco y que a su vez generan una alteracion del ultrasonido que regresa al transductor para crear las imagenes. Entre las posibles formas de analisis, las mas utilizadas son las que se basan en la medida de los parametros acusticos del tejido, y de estas, el Backscatter integrado es la mas conocida. Las ondas ultrasonicas que, despues de hacer incidencia en el tejido, se dispersan en un angulo de 180° entre el transductor y el tejido se definen como «backscatter». El Backscatter integrado es, pues, la cuantificacion del ultrasonido que se refleja hacia el transductor desde las estructuras miocardicas o «scatterers». De esta manera se han estudiado multiples cardiopatias: hipertrofia, miocardiopatias, rechazo del corazon trasplantado, etc. Pero es el campo de la isquemia-viabilidad miocardica el mas interesante debido a la importancia en seleccionar, de forma no invasiva y con bajo coste, a los pacientes coronarios agudos que a pesar de importantes discinesias por ecocardiografia convencional y/o angiografia, la magnitud del Backscatter y/o su variacion ciclica nos indican viabilidad miocardica y, por tanto, estos pacientes se pueden beneficiar de terapias de revascularizacion urgente.

Left ventricular (LV) volume and ejection fraction estimation from two-dimensional echocardiograms requires off-line analysis and time-consuming manual tracing. LV volumes may be estimated on-line with a semiautomated edge detection echocardiographic system [also known as acoustic quantification (AQ)], but there are few data that compare volumes obtained from the AQ method with volumes derived from off-line manual tracing of conventional two-dimensional echocardiograms. Echocardiograms were performed in 48 patients at two medical centers. LV volumes were measured from the apical view with the method of discs and area-length formulae and from the parasternal short-axis view with the modified ellipsoid model. Based on the criterion of >/=75% endocardial visualization, 25 (52%) of the short-axis views and 14 (29%) of the apical views were analyzed by a single investigator. End-diastolic and end-systolic LV volumes derived on line with the AQ system showed a very strong linear association with off-line, manually traced volumes (r = 0.96-0.99). Correlations for ejection fraction also were strong (r = 0.90-0.96). End-diastolic and end-systolic LV volumes, measured from the apical views, were underestimated by the AQ method. However, because the error was in the same direction, ejection fractions measured with the AQ system and by manual tracing of conventional echocardiograms were similar. Estimation of ejection fraction using a semiautomated edge detection echocardiographic system is a promising method for noninvasive evaluation of systolic function in carefully selected patients.

We measured the regional disparity in backscattered ultrasound by means of obtaining integrated backscatter images of 10 healthy subjects and placing a region of interest in 18 distinct positions. A computer model simulating the short-axis view was implemented on the basis of previously measured values for the anisotropic ultrasonic properties of myocardium. Measurements showed that the integrated backscatter value was greatest for the anterior septum and decreased by 15.9 ± 3.5 dB for the lateral wall and 17.7 ± 3.5 dB for the inferior septum. The value in the posterior wall was 8.1 ± 3.8 dB below the value for the anterior septum. The regional variation of backscatter predicted with the simulation correlated well with the clinical measurements. These results suggested that analyses based on measurements of backscatter may require compensation for the inherent anisotropic properties of myocardium. (J Am Soc Echocardiogr 1998;11:929-37.)

In this paper, we report the effects of inherent tissue anisotropy on the spectral properties of backscattered ultrasound when measured with a commercially-available imaging system. We insonified five specimens of bovine tendon immersed in a water tank and rotated in 10° increments while being imaged with a Hewlett-Packard Sonos 1500 system. The backscattered RF signals corresponding to each angle of insonification were digitized and the spectral characteristics of the backscattered ultrasound were determined. The mean anisotropy, defined as the average difference between values at perpendicular and parallel insonification, for band-limited estimates of backscattered power, centroid frequency, upper-band to lower-band power ratio, and upper-band to total-band power ratio were found to be 24.6 ± 1.1 dB, 142 ± 27 kHz, 32 ± 13%, and 22 ± 5%, respectively (mean ± SE). The magnitude of each of these backscatter spectral parameters was larger at perpendicular insonification compared with the corresponding values at parallel insonification, consistent with previous measurements of the inherent anisotropy of ultrasonic attenuation and backscatter in tissue.

Diagnostic ultrasonic characterization of the heart is designed to assess the state of the myocardium with ultrasonic parameters that relate to structural or functional components of cardiac muscle. The potential cross fertilization of ideas and methods between those borne out of research in quantitative nondestructive evaluation of materials and those borne out of research in diagnostic medical applications in the area of ultrasonics represents an attractive goal. In this paper we describe our approach to tissue characterization of the heart based on quantitative ultrasonic imaging. We discuss methods of ultrasonic tissue characterization applied in laboratory and clinical investigations. Specific examples of the application of clinical quantitative tissue characterization include measurements of the hearts of patients with remote myocardial infarction, dilated cardiomyopathy, acute myocardial ischemia, and hearts of patients with diabetes. The role of anisotropy in quantitative tissue characterization a...

Aims: To illustrate the association between a patent foramen ovale (PFO) and paradoxical embolization. Methods and results: We report a unique case of a paradoxical embolization across a PFO noted during a transesophageal echocardiographic study. Serial images demonstrate the thrombus migrating from the superior vena cava to the left atrium across the PFO. Conclusions: This case establishes the association between the PFO and paradoxical embolism unequivocally. a 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.

Left ventricular hypertrophy (LVH) is associated with decreased contractile response to inotropic stimulation in animal models, but this has not been documented in humans. To determine whether LVH is associated with decreased myocardial contractile reserve, we measured left ventricular mass, heart rate-corrected velocity of circumferential fiber shortening (Vcfc), end-systolic stress, and LV ejection fraction (LVEF) in patients with LVH and increased end-systolic stress (n = 6) and in patients without LVH (n = 7) who had a normal response to dobutamine stress echocardiography (increased LVEF and no wall motion abnormalities). The afterload-dependent indexes of left ventricular systolic performance were normal at baseline and showed significant increases at peak dobutamine dose (LVH group: Vcfc 0.91 +/- 0.11 to 1.76 +/- 0.59, p = 0.006; LVEF 49 +/- 5 to 65 +/- 6, p = 0.001; group without LVH: Vcfc 1.16 +/- 0.24 to 1.99 +/- 0.36, p = 0.001; LVEF 61 +/- 6 to 68 +/- 6, p = 0.05). The Vcfc/ end-systolic stress relation, a load-independent index of myocardial contractility, rose in a dose-dependent fashion in both groups, but the increment was significantly less for patients with LVH (p < 0.02), suggesting a blunted myocardial contractile reserve to inotropic stimulation. The change in heart rate-corrected velocity of circumferential fiber shortening per unit of change in end-systolic stress in each patient at each dobutamine dose showed a linear and inverse relationship. The increment in heart rate-corrected velocity of circumferential fiber shortening for a given reduction in end-systolic stress was larger in patients without LVH than in patients with LVH (p = 0.01). These results suggest that in patients with LVH and increased end-systolic stress, ventricular performance is maintained at the expense of limited myocardial contractile reserve, and that inotropic stimulation unmasks this abnormality, despite a normal response in LVEF and velocity of circumferential fiber shortening. This approach may identify patients with LVH at risk of developing systolic dysfunction and heart failure.

The purpose of this study was to determine the relation between increased myocardial wall thickening during inotropic stimulation and quantitative acoustic properties of normal myocardium in humans. We first validated a new 2-dimensional ultrasonic backscatter imaging approach for measurement of cyclic variation in the parasternal long-axis view against conventional M-mode integrated backscatter technique in 41 patients and controls (group A). We then performed 2-dimensional ultrasonic integrated backscatter imaging in 18 patients (group B) with normal segmental function at baseline to determine the magnitude of the cyclic variation of the septum and the posterior wall before and during infusion of dobutamine (10 and 20 microgram/kg/min). Group A patients showed a close correlation of the cyclic variation obtained by the new 2-dimensional ultrasonic integrated backscatter imaging approach and the conventional M-mode technique. Group B patients had mean values of cyclic variation that remained unchanged in the septum (4.4 +/- 1.4, 4.3 +/- 1.7, and 4.8 +/- 1.6 dB at baseline and at each dobutamine stage, respectively, p = NS) and in the posterior wall (6.4 +/- 1.7, 6.4 +/- 1.8 and 6.1 +/- 1.9 dB, respectively, p = NS) despite progressive dobutamine-induced increases in percent wall thickening (septum: 38 +/- 10% to 57 +/- 17% and 68 +/- 19%, respectively, and posterior wall 42 +/- 13% to 72 +/- 20% and 77 +/- 18%, respectively; both p0.001 vs baseline for both walls). Thus, physical properties of normal myocardium remain unchanged during inotropic stimulation.

In conclusion, myocardial tissue characterization with quantitative ultrasonic indices descriptive of the physical state of the tissue is a promising approach to complement conventional echocardiography in the evaluation of patients with coronary artery disease. In particular, differentiation among hibernating, stunned and scarred myocardium may be possible on the basis of the experience accumulated thus far.

Objectives. This work proposes a self-consistent assessment methodology for quantitative evaluation of any combination of diagnostic features, with the immediate goal of quantitatively assessing the discriminating power in diabetic patients of features derived from ultrasound backscatter from myocardium. Background. Four features from analysis of left ventricular myocardial ultrasound backscatter have previously been shown to be sensitive to potentially cardiomyopathic changes in patients with insulin-dependent diabetes mellitus who have no overt heart disease. The measured features were significantly different between such patients and normal control subjects, as well as among groups of such patients with and without systemic complications of the disease. The quantitative discriminating potential of the features was not assessed. Methods. Multivariate classifier functions were constructed and analyzed by using the methodology of the receiver operating characteristic curve, which allows quantitative assessment of the discriminating power of these features, alone or in combination. The area under the receiver operating characteristic curve—the true positive rate averaged over all false positive rates—was used as a summary measure of performance. Results. In distinguishing patients with insulin-dependent diabetes mellitus from normal control subjects, the most discriminating combination of ultrasound features for the detection of such changes in these patients yielded receiver operating characteristic curves with area measures of ∼0.80; for such patients with retinopathy the measure increased to 0.90. This performance is comparable to that of many commonly used diagnostic tests. Conclusions. A self-consistent set of evaluation methodologies has quantitatively demonstrated the sensitivity of four ultrasound backscatter features to otherwise latent changes in myocardial structure that accompany the evolution of insulin-dependent diabetes mellitus. The results are remarkable in themselves and suggest the potential of the features for the general field of cardiac ultrasound tissue characterization.

Right ventricular dysfunction may occur soon after cardiac transplantation. Factors suggested to be responsible for right ventricular dysfunction include prolonged transplantation ischemic time, pulmonary hypertension, or early rejection. Right ventricular and left ventricular fractional area change (FAC) and ejection fraction (EF) were prospectively measured by two-dimensional (2D) echocardiography 2 days after transplantation (while under inotropic support) and at discharge (mean day 19, range 9-60) in 18 patients by the area-length method. A significant increase in right ventricular FAC (0.38 ± 0.08 to 0.44 ± 0.06, P = 0.025) and right ventricular EF (0.53 ± 0.08 to 0.60 ± 0.08, P = 0.015) was observed at discharge compared to day 2. Left ventricular FAC and EF did not change significantly (0.43 ± 0.07 to 0.40 ± 0.06 and 0.61 ± 0.09 to 0.56 ± 0.07, respectively). Right ventricular FAC (< 0.35) and right ventricular EF (< 0.45) was impaired in 4 patients (22%) 2 days after transplantation (all had normal left ventricular function) but normalized by discharge. There was no correlation between right ventricular function and donor ischemic time, hemodynamics, or early rejection (one patient). Only one patient died before discharge (with normal right ventricular and left ventricular function). Impaired right ventricular function after cardiac transplantation is transient, associated with normal left ventricular function, and may be related to inadequate right ventricular myocardial preservation. Right ventricular function improves in nearly all patients by discharge.

Automatic boundary detection (ABD) is a new echocardiographic modality providing continuous on-line measurements of cavitary area throughout the cardiac cycle. The maze procedure is a new surgical intervention designed to restore sinus rhythm and mechanical atrial contraction as a definitive treatment for patients with atrial fibrillations for whom medical therapy has failed. To evaluate whether ABD may define left atrial function in patients after the maze procedure, we obtained pulsed Doppler recordings of mitral inflow velocity and echocardiographic ABD in 25 patients, 6 +/- 2 months after the maze procedure. We measured the left atrial end-systolic cavitary area, mid-diastolic area before atrial contraction, and end-diastolic area (in square centimeters). Left atrial contraction by Doppler was compared with that derived by ABD in patients who underwent the maze procedure and control subjects (n = 13), both qualitatively and quantitatively (atrial filling fraction vs active atrial contraction [ABD] where atrial contraction (in percent) = (mid-diastolic area - end-diastolic area) x 100/(end-systolic area - end-diastolic area in percent]). Restoration of atrial contraction after the maze procedure was detected by Doppler in 19 patients (76%) and by ABD in 21 patients (84%). The atrial filling fraction was 19 +/- 4% in patients compared with values of 34% +/- 8% in control subjects (p < 0.001). By ABD atrial contraction was 20% +/- 6% in patients whereas control subjects exhibited values of 41% +/- 14% p < 0.001). The Doppler-derived atrial filling fraction and ABD-derived atrial contraction were closely correlated (r = 0.91; p < 0.001; y = 0.59x + 8.6). Thus Doppler techniques complemented by ABD provide direct quantitative indexes of left atrial function throughout the cardiac cycle. Although left atrial contraction and filling are reduced after the maze procedure, left atrial function is restored in most patients with a history of atrial fibrillation, and echocardiographic ABD is a sensitive technique for its detection.

In this study, we present the karyotypic features of two taxa, curema and gaimardianus (genus Mugil), supposed to be synonyms by some authors. Their cytogenetic differences are conspicuous and unambiguous, providing evidence that Mugil curema and Mugil gaimardanus are two valid nominal species.

A case of cardiogenic shock after mitral valve repair that was successfully treated with a ventricular assist device is reported. Evaluation of left ventricular function performed on line by serial trans-esophgeal echocardiography (TEE) with automatic border detection (ABD) showed improvement in left ventricular function from day 2 to day 6 (fractional area change 7% at day 2; 38% at day 6). TEE with ABD is a promising new approach for online evaluation of ventricular function, and has a promising role in determining the timing for successful removal of mechanical assist devices after surgical intervention.

Recent modications in two-dimensional echocardiography imaging include automatic boundary detection (ABD) that permits instantaneous quantification of left ventricular (LV) function. To define its clinical application from different views in consecutive patients ( n = 68), we performed both conventional two-dimensional imaging and ABD with lateral gain compensation and compared the ability of each method for visualization of myocardial segments. From each view (short-axis and apical four- and two-chamber), the LV was divided into six wall segments. The short-axis view was obtained successfully in 53 of 68 patients; of the possible 318 segments, 96% were visualized adequately by two-dimensional echocardiography and 89% by ABD. From the four-chamber view, obtained in 63 of 68 patients, visualization of 378 possible segments was 93% by two-dimensional imaging and 86% by ABD, respectively. From the two-chamber view obtained in 58 of 68 patients, the success rate was 88% and 80% (two-dimensional imaging and ABD, respectively). ABD detected LV endocardial/blood borders in all six segments of each view in 73%, 72%, and 72% of cases, concordant with adequate two-dimensional imaging. Discrepancies between two-dimensional imaging and ABD were usually in the short-axis inferior and lateral, four-chamber lateral, and two-chamber anterior segments. There were 46 patients with normal LV wall motion and 22 with wall-motion abnormalities. The average time required to perform ABD was 375 seconds (range 180 to 780 seconds). Thus ABD is clinically applicable, has similar yield in parasternal and apical views, does not add excessive time for analysis, and provides comparable visualization of LV segments if acceptable conventional two-dimensional images are obtained.

Two-dimensional echocardiography is widely used for assessment of cardiac chamber size and function. A new method for real-time quantitative assessment of left ventricular systolic function using automatic boundary detection (ABD) has been developed based on principles of quantitative ultrasound backscatter imaging of the myocardium. The clinical accuracy of ABD for measurement of cardiac chamber areas and volumes has been validated against conventional two-dimensional echocardiography, transesophageal echocardiography, radionuclide ventriculography, and left ventriculography. Left ventricular diastolic function can also be evaluated by ABD, and the results complement those obtained indirectly by pulsed Doppler echocardiographic recordings of the diastolic mitral flow velocity. Recently, ABD has also been used to evaluate left atrial chamber dimensions and atrial function. Thus, real-time ABD is a new echocardiographic method for quantitative assessment of cardiac function that obviates the need for off-line analysis of video images.

To determine the feasibility and accuracy of biplane transesophageal echocardiography (TEE) with automatic boundary detection (ABD) for the estimation of left ventricular areas, we examined 19 consecutive patients with the use of this technique. In addition, we evaluated the utility of lateral gain compensation (LGC) to improve the online tracking of the ABD algorithm on the lateral endocardial-blood boundary of the echocardiographic image. The transverse plane short-axis TEE view and the longitudinal plane two chamber TEE view were used for the analysis. A semiquantitative estimate (in degrees) of the endocardial circumference, in which the boundary was correctly identified and tracked on line, improved from a mean of 198 degrees to 360 degrees with LGC (P less than 0.001). Results of comparisons of offline and online biplane TEE cavity areas revealed excellent correlations of values for the 16 patients (84%) in whom adequate transverse plane short-axis images were obtained (r values greater than 0.9 at systole and diastole). The correlation was also excellent (r values greater than 0.9) in the nine patients in whom longitudinal plane two-chamber views adequate for ABD analysis were obtained at systole and diastole. LGC significantly improved the accuracy of endocardial detection and tracking, which otherwise would be limited due to the anisotropic properties of the myocardium. Thus, ABD during biplane TEE may be feasible in a significant number of patients and accurately reflects left ventricular areas when compared with offline methods.

Background— The diabetic heart exhibits increased left ventricular (LV) mass and reduced ventricular function. However, this relationship has not been studied in patients with aortic stenosis (AS), a disease process that causes LV hypertrophy and dysfunction through a distinct mechanism of pressure overload. The aim of this study was to determine how diabetes mellitus (DM) affects LV remodeling and function in patients with severe AS. Methods and Results— Echocardiography was performed on 114 patients with severe AS (mean aortic valve area [AVA], 0.6 cm 2 ) and included measures of LV remodeling and function. Multivariable linear regression models investigated the independent effect of DM on these aspects of LV structure and function. Compared to patients without diabetes (n=60), those with diabetes (n=54) had increased LV mass and LV end-systolic and end-diastolic dimensions, and decreased LV ejection fraction (EF) and longitudinal systolic strain (all P P =0.01), LV end-systolic dimension (β=0.5 cm, P =0.008), and LV end-diastolic dimension (β=0.3 cm, P =0.025). After also adjusting for LV mass, DM was associated with reduced longitudinal systolic strain (β=1.9%, P =0.023) and a trend toward reduced EF (β=−5%, P =0.09). Among patients with diabetes, insulin use (as a marker of disease severity) was associated with larger LV end-systolic dimension and worse LV function. LV mass was a strong predictor of reduced EF and systolic strain (both P Conclusions— DM has an additive adverse effect on hypertrophic remodeling (increased LV mass and larger cavity dimensions) and is associated with reduced systolic function in patients with AS beyond known factors of pressure overload.

Objectives. This study was designed to determine in patients with advanced coronary disease whether prediction of recovery of mechanical function after coronary revascularization could be accomplished more effectively by positron emission tomography (PET) with Carbon-11 (11C)-acetate than by PET with fluorine-18 (18F)-fluorodeoxyglucose.Background.Results of previous studies have demonstrated that preservation of myocardial oxidative metabolism (measured by PET with 11C-acetate) is necessary for recovery of systolic function after coronary revascularization.Methods. Myocardial oxidative metabolism was quantified before revascularization in 34 patients by the analysis of the rate of myocardial clearance of 11C-acetate. Metabolism of glucose was assessed by analysis of uptake of 18F-fluorodeoxyglucose. Receiver operating characteristic curves for predicting functional recovery were derived for the measurements of oxidative metabolism and glucose metabolism. In addition, criteria for prediction of recovery of function based on measurements of oxidative metabolism and glucose metabolism were developed and compared.Results. Analysis of receiver operating characteristic curves indicated that estimates of oxidative metabolism were more robust in predicting functional recovery than were estimates of glucose metabolism (p < 0.02). Moreover, thershold criteria with 11C-acetate exhibited superior positive and negative predictive values (67% and 89%, respectively) than did the criteria with 18F-fluorodeoxyglucose (52% and 81%, respectively), p < 0.01. In segments with initially severe dysfunction, estimates of oxidative metabolism tended to be more robust than estimates of glucose metabolism in predicting functional recovery. Moreover, in such segments, the threshold criteria with 11C-acetate to exhibit superior positive and negative predictive values (85% and 87%, respectively) than did the criteria with 18F-fluorodeoxyglucose (72% and 82%, respectively), although statistical significance was not achieved.Conclusions. In patients with advanced coronary artery disease, the extent to which functional recovery can be anticipated after coronary revascularization can be delineated accurately by quantification of regional oxidative metabolism by PET with 11C-acetate.

Abnormalities of the left atrioventricular (AV) (tricuspid) valve and pulmonic stenosis are part of the spectrum of manifestations in patients with corrected transposition of the great arteries (L-TGA). However, the utility of Doppler color flow imaging combined with two-dimensional echocardiography in L-TGA has not been established. Thus, we evaluated 14 adults (mean age 33 ± 8 [SD] years) with L-TGA. Two-dimensional echocardiography demonstrated Ebstein's anomaly in five patients. Color flow imaging detected left AV valve regurgitation in 13 (moderate to severe in six); the other patient had a prosthetic valve. Right AV valve regurgitation was detected in two (mild in both). Aortic regurgitation was present in five (moderate in three). Pulmonic regurgitation was present in nine (moderate to severe in three). Pulmonic stenosis was detected in three (subvalvular in two, valvular in one) and two patients had pulmonary atresia. One patient had a bicuspid aortic valve with mild stenosis. Mean right ventricular ejection fraction (apical, area-length) was 44%; only 1 of 9 patients had a value > 55%. Thus, two-dimensional Doppler echocardiography with color flow imaging detects a high incidence of systemic AV valvular regurgitation and reduced right (systemic) ventricular systolic function in adults with L-TGA. (ECHOCARDIOGRAPHY, Volume 10, November 1993)

The quantitative applications of echocardiography in clinical practice are well known. The measurements of cardiac chamber dimensions, wall thickness, and overall performance have been uniformly adopted. An important emerging ultrasound modality known as tissue characterization of the myocardium has evolved from experimental studies to clinical investigation. The ability to quantitate myocardial acoustic properties by the measurement of integrated backscatter (in decibels) provides direct assessment of myocardial structural characteristics and contractile performance, to complement conventional two-dimensional imaging of ventricular wall motion and wall thickening. Despite the considerable amount of work that has been done, there are several areas of research that need to be further investigated before widespread clinical use of these techniques is possible. Specifically, absolute values of myocardial backscatter are not yet obtainable with the current instrumentation; only the relative change in backscatter during the cardiac cycle (cyclic variation) has been defined and employed in clinical studies. This review summarizes the principles of tissue characterization and the results of several clinical studies, specifically those carried out in patients with coronary artery disease and cardiomyopathies.