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1.
Hum Reprod ; 34(4): 751-757, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30865256

RESUMO

STUDY QUESTION: Does an informed group of citizens endorse the clinical use of mitochondrial donation in a country where this is not currently permitted? SUMMARY ANSWER: After hearing balanced expert evidence and having opportunity for deliberation, a majority (11/14) of participants in a citizens' jury believed that children should be able to be born using mitochondrial donation. WHAT IS KNOWN ALREADY: Research suggests that patients, oocyte donors and health professionals support mitochondrial donation to prevent transmission of mitochondrial disease. Less is known about public acceptability of this novel reproductive technology, especially from evidence using deliberative methods. STUDY DESIGN, SIZE, DURATION: This study comprised a citizens' jury, an established method for determining the views of a well-informed group of community members. The jury had 14 participants, and ran over one and a half days in 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Jurors were members of the public with no experience of mitochondrial disease. They heard and engaged with relevant evidence and were asked to answer the question: 'Should Australia allow children to be born following mitochondrial donation?' MAIN RESULTS AND THE ROLE OF CHANCE: Eleven jurors decided that Australia should allow children to be born following mitochondrial donation; 7 of whom added conditions such as the need to limit who can access the intervention. Three jurors decided that children should not (or not yet) be born using this intervention. All jurors were particularly interested in the reliability of evidence, licensing/regulatory mechanisms and the rights of children to access information about their oocyte donors. LIMITATIONS, REASONS FOR CAUTION: Jurors' views were well informed and reflected critical deliberation and discussion, but are not intended to be representative of the whole population. WIDER IMPLICATIONS OF THE FINDINGS: When presented with high quality evidence, combined with opportunities to undertake structured deliberation of novel reproductive technologies, members of the public are able to engage in detailed discussions. This is the first study to use an established deliberative method to gauge public views towards mitochondrial donation. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by a University of Sydney Industry and Community Collaboration Seed Award (2017), which was awarded contingent on additional funding from the Mito Foundation. Additional funding was provided by the Mito Foundation. The Foundation was not involved in jury facilitation or deliberation, nor analysis of research data. TRIAL REGISTRATION NUMBER: Not applicable.


Assuntos
Atitude , Doenças Mitocondriais/prevenção & controle , Terapia de Substituição Mitocondrial/legislação & jurisprudência , Terapia de Substituição Mitocondrial/métodos , Doação de Oócitos/legislação & jurisprudência , Doação de Oócitos/métodos , Opinião Pública , Adolescente , Adulto , Idoso , Austrália , Tomada de Decisões , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Formulação de Políticas , Adulto Jovem
2.
Child Care Health Dev ; 40(3): 301-8, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-23445484

RESUMO

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is now the most common reason for a child to present to a paediatrician in Australia. Stimulant medications are commonly prescribed for children with ADHD, to reduce symptoms and improve function. In this study we investigated the factors that influence paediatricians' decisions about prescribing stimulant medications. METHOD: In-depth, semi-structured interviews were conducted with paediatricians (n = 13) who were purposively recruited so as to sample a broad demographic of paediatricians working in diverse clinical settings. Paediatricians were recruited from public outpatient and private paediatrician clinics in Victoria, Australia. The interviews were audio-recorded and transcribed verbatim for thematic analysis. Paediatricians also completed a questionnaire describing their demographic and practice characteristics. RESULTS: Our findings showed that the decision to prescribe is a dynamic process involving two key domains: (1) weighing up clinical factors; and (2) interacting with parents and the patient along the journey to prescribing. Five themes relating to this process emerged from data analysis: comprehensive assessments that include history, examination and information from others; influencing factors such as functional impairment and social inclusion; previous success; facilitating parental understanding including addressing myths and parental confusion; and decision-making model. CONCLUSIONS: Paediatricians' decisions to prescribe stimulant medications are influenced by multiple factors that operate concurrently and interdependently. Paediatricians do not make decisions about prescribing in isolation; rather, they actively involve parents, teachers and patients, to arrive at a collective, well-informed decision.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Estimulantes do Sistema Nervoso Central/uso terapêutico , Tomada de Decisões , Médicos/psicologia , Padrões de Prática Médica/estatística & dados numéricos , Adulto , Idoso , Atitude do Pessoal de Saúde , Prescrições de Medicamentos/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Relações Médico-Paciente , Relações Profissional-Família , Vitória
3.
J Bioeth Inq ; 18(4): 573-587, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34741699

RESUMO

Being a healthcare professional in both paediatric and adult hospitals will mean being exposed to human tragedies and stressful events involving conflict, misunderstanding, and moral distress. There are a number of different structured approaches to reflection and discussion designed to support healthcare professionals process and make sense of their feelings and experiences and to mitigate against direct and vicarious trauma. In this paper, we draw from our experience in a large children's hospital and more broadly from the literature to identify and analyse four established approaches to facilitated reflective discussions. Each of the four approaches seeks to acknowledge the stressful nature of health professional work and to support clinicians from all healthcare professions to develop sustainable skills so they continue to grow and thrive as health professionals. Each approach also has the potential to open up feelings of uncertainty, frustration, sorrow, anguish, and moral distress for participants. We argue, therefore, that in order to avoid unintentionally causing harm, a facilitator should have specific skills required to safely lead the discussion and be able to explain the nature, scope, safe application, and limits of each approach. With reference to a hypothetical but realistic clinical case scenario, we discuss the application and key features of each approach, including the goals, underpinning theory, and methods of facilitation.


Assuntos
Pessoal de Saúde , Estresse Ocupacional , Trauma Psicológico , Humanos , Pessoal de Saúde/psicologia , Hospitais , Estresse Ocupacional/psicologia
4.
J Med Ethics ; 35(12): 722-8, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19948926

RESUMO

The concept of selecting for a disability, and deafness in particular, has triggered a controversial and sometimes acrimonious debate between key stakeholders. Previous studies have concentrated on the views of the deaf and hard of hearing, health professionals and ethicists towards reproductive selection for deafness. This study, however, is the first of its kind examining the views of hearing children of deaf adults towards preimplantation genetic diagnosis and prenatal diagnosis to select for or against deafness. Hearing children of deaf adults (or CODAs, as they call themselves, and are widely known in the deaf community) straddle both the deaf and hearing worlds, and this dual perspective makes them ideally placed to add to the academic discourse concerning the use of genetic selection for or against deafness. The study incorporated two complementary stages, using initial, semistructured interviews with key informants (CODAs and health professionals) as a means to guide the subsequent development of an electronic survey, completed anonymously by 66 individuals. The participants shared many of the same views as deaf individuals in the D/deaf (or "culturally deaf") community. The similarities extended to their opinions regarding deafness not being a disability (45.5% believed deafness was a distinct culture rather than a disability), their ambivalence towards having hearing or deaf children (72.3% indicated no preference) and their general disapproval of the use of genetic technologies to select either for or against deafness (60% believed that reproductive technologies, when used to select for or against deafness, should not be available to the community).


Assuntos
Atitude Frente a Saúde , Surdez/genética , Testes Genéticos/psicologia , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Diagnóstico Pré-Natal/psicologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Surdez/diagnóstico , Surdez/psicologia , Feminino , Aconselhamento Genético , Testes Genéticos/ética , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Pais/psicologia , Diagnóstico Pré-Natal/ética , Seleção Genética , Adulto Jovem
5.
Mol Genet Metab ; 94(2): 143-7, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18395481

RESUMO

Non-ketotic hyperglycinaemia (NKH) is a devastating neurometabolic disorder leading, in its classical form, to early death or severe disability and poor quality of life in survivors. Affected neonates may need ventilatory support during a short period of respiratory depression. The transient dependence on ventilation dictates urgency in decision-making regarding withdrawal of therapy. The occurrence of patients with apparent transient forms of the disease, albeit rare, adds uncertainty to the prediction of clinical outcome and dictates that the current practice of withholding or withdrawing therapy in these neonates be reviewed. Both bioethics and law take the view that treatment decisions should be based on the best interests of the patient. The medical-ethics approach is based on the principles of non-maleficence, beneficence, autonomy and justice. The law relating to withholding or withdrawing life-sustaining treatment is complex and varies between jurisdictions. Physicians treating newborns with NKH need to provide families with accurate and complete information regarding the disease and the relative probability of possible outcomes of the neonatal presentation and to explore the extent to which family members are willing to take part in the decision making process. Cultural and religious attitudes, which may potentially clash with bioethical and juridical principles, need to be considered.


Assuntos
Tomada de Decisões , Ética Médica , Hiperglicinemia não Cetótica/terapia , Neonatologia/ética , Neonatologia/legislação & jurisprudência , Humanos , Hiperglicinemia não Cetótica/diagnóstico , Recém-Nascido , Responsabilidade Legal , Cuidados para Prolongar a Vida , Suspensão de Tratamento/legislação & jurisprudência
6.
J Anat ; 213(3): 325-35, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18624829

RESUMO

Human 2D : 4D ratios (measures of the relative lengths of index and ring fingers) attract considerable research interest because they exhibit sexual dimorphism and are associated with various morphological, physiological and behavioural traits as well as sporting abilities and medical conditions. In an attempt to identify potential confounding factors in such studies, we have examined how relative and absolute digit lengths vary with gender and tested whether they are influenced by age, right-left asymmetry and hand preference. Participants between 4 and 60 years of age were recruited from local educational sites. Hand photocopies and calliper measurement were used to obtain digit lengths. We employed linear regression analysis to examine the growth trajectories of individual digits, analyses of variance to isolate main and interaction effects of age, gender and hand preference, and paired t-tests to identify lateral asymmetries. Both digits exhibited biphasic growth with an early growth phase followed by a stable length phase. Digits in females attained their maximum length about 2.2 years (dextral subjects) or 5.1 years (sinistral subjects) earlier than those in males. Sexual dimorphism in 2D : 4D ratios was apparent by 4 years of age and age changes in ratios depended on gender, side and hand preference. Relative and absolute lengths displayed age, gender, hand-preference and age x gender interaction effects. Lengths tended to be greater in females in younger subjects and greater in males in older subjects. Ratios tended to be greater in sinistral subjects. In dextral subjects, significant lateral asymmetries in 2D lengths were seen at all ages but asymmetries in males and 4D lengths seemed to be age-dependent. We conclude that age, lateral asymmetry and hand preference are potential confounding factors and that future study designs should take account of these as well as other known confounders such as ethnicity, birth order, menstrual cycle phase and sexual preference.


Assuntos
Envelhecimento/fisiologia , Dedos/anatomia & histologia , Caracteres Sexuais , Adolescente , Adulto , Criança , Pré-Escolar , Estudos Transversais , Feminino , Dedos/crescimento & desenvolvimento , Lateralidade Funcional , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade
7.
J Med Genet ; 43(11): 850-5, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16840571

RESUMO

BACKGROUND: There is a lack of information on prevalence, cause and consequences of slight/mild bilateral sensorineural hearing loss (SNHL) in children. We report the first systematic genetic analysis of the GJB2 gene in a population-derived sample of children with slight/mild bilateral SNHL. METHODS: Hearing tests were conducted in 6240 Australian elementary school children in Grades 1 and 5. 55 children (0.88%) were found to have a slight/mild sensorineural hearing loss. 48 children with slight/mild sensorineural hearing loss and a matched group of 90 children with normal hearing participated in a genetic study investigating mutations in the GJB2 gene, coding for connexin 26, and the presence of the del(GJB6-D13S1830) and del(GJB6-D13S1854) deletions in the GJB6 gene, coding for connexin 30. RESULTS: Four of 48 children with slight/mild sensorineural hearing loss were homozygous for the GJB2 V37I change. The four children with homozygous V37I mutations were all of Asian background and analysis of SNPs in or near the GJB2 gene suggests that the V37I mutation arose from a single mutational event in the Asian population. DISCUSSION: Based on the prevalence of carriers of this change we conclude that V37I can be a causative mutation that is often associated with slight/mild sensorineural hearing loss. No other children in the slight/mild hearing loss group had a hearing loss related to a GJB2 mutation. One child with normal hearing was homozygous for the R127H change and we conclude that this change does not cause hearing loss. Two children of Asian background were carriers of the V37I mutation. Our data indicate that slight/mild sensorineural hearing loss due to the GJB2 V37I mutation is common in people of Asian background.


Assuntos
Conexinas/genética , Perda Auditiva Bilateral/genética , Perda Auditiva Neurossensorial/genética , Mutação , Alelos , Austrália , Criança , Conexina 26 , Análise Mutacional de DNA , Feminino , Testes Genéticos , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Instituições Acadêmicas
10.
J Am Coll Cardiol ; 6(4): 825-30, 1985 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3897342

RESUMO

Myocardial contrast echocardiography has been shown to accurately assess the area at risk for necrosis after acute coronary occlusion in the experimental model. The area at risk as determined by this method, however, has been defined in different ways depending on the model used. Some investigators have injected the contrast agent proximal to the site of coronary occlusion (left main coronary artery or aorta) and defined the area at risk as the segment of myocardium not showing a contrast effect (negative risk area). Others have injected the contrast agent directly into the occluded vessel and have defined the area at risk as that showing contrast enhancement (positive risk area). To evaluate whether the areas at risk determined by these two techniques are identical, six open chest dogs were studied using both methods. The area at risk was slightly but significantly larger when the contrast agent was injected into the occluded vessel than when it was injected proximally into the left main coronary artery (4.98 +/- 1.69 versus 3.97 +/- 1.27 cm2, p less than 0.01). It is concluded that the site of injection of the contrast agent significantly influences the determination of area at risk. Therefore, data obtained by the two techniques should not be used interchangeably, and in a given study the area at risk should be measured consistently using one technique.


Assuntos
Doença das Coronárias/diagnóstico , Ecocardiografia , Animais , Meios de Contraste/administração & dosagem , Circulação Coronária , Doença das Coronárias/patologia , Cães , Ecocardiografia/métodos , Necrose , Pressão , Ultrassonografia
11.
J Am Coll Cardiol ; 6(6): 1422-7, 1985 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3864856

RESUMO

Two patients presenting with acute pulmonary edema were found to have a left atrial cardiac osteogenic sarcoma (primary and secondary). The two-dimensional echocardiographic appearance in both cases mimicked that of atrial myxoma. However, two echocardiographic features (that is, tumor extension into pulmonary veins and origin from nonseptal atrial walls) suggested the presence of a nonmyxomatous cardiac tumor.


Assuntos
Ecocardiografia , Neoplasias Cardíacas/diagnóstico , Mixoma/diagnóstico , Osteossarcoma/diagnóstico , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
12.
J Am Coll Cardiol ; 8(4): 971-4, 1986 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3760370

RESUMO

In a 69 year old woman with a "sticking" Björk-Shiley mitral prosthesis, the diagnosis was suggested by both the two-dimensional and the Doppler ultrasound examinations. In particular, the findings of early diastolic paradoxic septal motion, intermittent delayed opening of the prosthetic disc and variable timing of the onset of mitral valve inflow were believed to be diagnostic of a sticking tilting disc prosthesis.


Assuntos
Ecocardiografia , Próteses Valvulares Cardíacas , Contração Miocárdica , Idoso , Feminino , Septos Cardíacos/fisiopatologia , Humanos , Valva Mitral , Falha de Prótese
13.
J Am Coll Cardiol ; 7(2): 383-92, 1986 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3944358

RESUMO

To define the in vivo relation between abnormal wall motion and the area at risk for necrosis after acute coronary occlusion, 11 open chest dogs were studied. Five dogs underwent left anterior descending coronary artery occlusion and six underwent left circumflex artery occlusion. Area at risk was defined at five short-axis levels (mitral valve, chordal, high and low papillary muscle and apex) using myocardial contrast echocardiography. Wall motion was measured in the cycles preceding injection of contrast medium. Two observers used two different methods to measure wall motion. In method A, end-diastolic to end-systolic fractional radial change for each of 32 endocardial targets was determined. The extent of abnormal wall motion was then calculated using three definitions of wall motion abnormality: akinesia/dyskinesia, fractional inward endocardial excursion of less than 10%, and fractional inward endocardial excursion of less than 20%. In method B, the information from the entire systolic contraction sequence was analyzed and correlated with a normal contraction pattern. The best linear correlation between area at risk (AR) and abnormal wall motion (AWM) was achieved using method B and expressed by the following linear regression: AWM = 0.92 AR + 3.0 (r = 0.92, p less than 0.0001, SEE = 1.7%). Of the three definitions of abnormality used in method A, the best correlation was achieved between area at risk and less than 10% inward endocardial excursion and was expressed by the following polynomial regression: AWM = -0.01 AR2 + 1.5 AR -0.14 (r = 0.92, p less than 0.001, SEE = 1.7%). These data demonstrate that there is a definite relation between area at risk and abnormal wall motion but that this relation varies depending on the method used to analyze wall motion. However, wall motion during acute ischemia is also influenced by the loading conditions of the heart. Because these may vary in a manner that is independent of the ischemic process, measurement of both risk area and abnormal motion may provide a more comprehensive assessment of cardiac function in myocardial ischemia than is provided by the measurement of either alone.


Assuntos
Doença das Coronárias/patologia , Ecocardiografia/métodos , Coração/fisiopatologia , Animais , Doença das Coronárias/fisiopatologia , Diatrizoato , Diatrizoato de Meglumina , Cães , Combinação de Medicamentos , Movimento , Necrose , Risco
14.
J Am Coll Cardiol ; 15(7): 1578-84, 1990 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2345237

RESUMO

Previous studies have shown that Doppler echocardiographic methods based on the continuity equation can accurately determine aortic valve area in patients with clinically significant aortic stenosis; nonetheless, methods based on the continuity equation are time-consuming and may not be technically possible in all subsets of patients. The purpose of this study was to develop and prospectively evaluate a simpler new noninvasive method for determining aortic valve area. With this new method, aortic valve area is obtained by dividing the percent fractional anteroposterior shortening at the midventricular level by 4V2, where V is the peak instantaneous Doppler-derived flow velocity across the aortic valve. In the first part of the study, the fractional shortening-velocity ratio was used to examine a group of 25 patients evaluated retrospectively. There was a highly significant linear relation between the fractional shortening-velocity ratio (FSVR) and the aortic valve area (AVA) determined by the Gorlin formula at cardiac catheterization: FSVR = 1.1(AVA) - 0.1 (r = 0.88; significance of slope p less than 0.001). Furthermore, a fractional shortening-velocity ratio less than 1.1 reliably identified all patients with clinically significant aortic stenosis (aortic valve area less than 1 cm2), whereas a fractional shortening-velocity ratio less than 0.8 reliably identified all patients with critical aortic stenosis (aortic valve area less than 0.7 cm2). This new method was then validated by prospectively applying the fractional shortening-velocity ratio to a group of 44 patients from two separate institutions.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Estenose da Valva Aórtica/diagnóstico , Ecocardiografia Doppler/métodos , Valva Aórtica/patologia , Valva Aórtica/fisiopatologia , Estenose da Valva Aórtica/fisiopatologia , Cateterismo Cardíaco , Ecocardiografia Doppler/normas , Estudos de Avaliação como Assunto , Humanos , Estudos Prospectivos , Estudos Retrospectivos
15.
J Am Coll Cardiol ; 16(2): 396-404, 1990 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2373818

RESUMO

Mitral valve areas determined by Doppler pressure half-time were compared with areas obtained by planimetry in two groups of patients with mitral stenosis: 24 patients without aortic regurgitation and 32 patients with more than grade 1 aortic regurgitation. The severity of aortic regurgitation was assessed by color flow mapping; 17 patients had grade 2, 10 had grade 3 and 5 had grade 4 aortic regurgitation. Regression equations for pressure half-time area versus planimetry mitral valve area were calculated separately for the aortic regurgitation (r = 0.88) and the nonaortic regurgitation group (r = 0.86); analysis of covariance revealed a significant (p less than 0.001) difference between the two groups leading to overestimation of planimetry area by the pressure half-time method in the aortic regurgitation group. The mitral valve areas in the group without regurgitation were best calculated with the expression 239/T1/2 (r = 0.77) as compared with a best fit of 195/T1/2 (r = 0.85) for the aortic regurgitation group. To elucidate the mechanisms affecting pressure half-time in aortic regurgitation, an in vitro model of mitral inflow in the presence of varying regurgitant volumes and different ventricular chamber compliances was used. Aortic regurgitation shortened directly measured pressure half-time proportional to the regurgitant fraction but an increase in left ventricular compliance could offset this effect. Finally, in a mathematic model of mitral inflow the competing effects of aortic regurgitation and chamber compliance could be confirmed. In conclusion, aortic regurgitation results clinically in a significant net shortening of pressure half-time leading to mitral valve area overestimation. However, the effect is moderate and individually unpredictable because of changes in chamber compliance.


Assuntos
Insuficiência da Valva Aórtica/fisiopatologia , Simulação por Computador , Ecocardiografia Doppler , Estenose da Valva Mitral/fisiopatologia , Modelos Cardiovasculares , Adulto , Idoso , Insuficiência da Valva Aórtica/complicações , Complacência (Medida de Distensibilidade) , Feminino , Ventrículos do Coração/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Estenose da Valva Mitral/complicações , Estenose da Valva Mitral/diagnóstico , Pressão
16.
J Am Coll Cardiol ; 14(2): 481-8, 1989 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2754133

RESUMO

Specific information regarding the relation between infarct thickness and regional systolic function is important to the overall understanding of both the pathophysiology of acute and subacute myocardial infarction and the functional benefits of myocardial salvage interventions designed to limit the transmural extent of infarction and thereby preserve left ventricular function. In the present study, quantitative computer-assisted two-dimensional echocardiography was used to define the relation between infarct thickness and systolic function in the acutely and subacutely infarcted canine left ventricle. Echocardiograms were obtained at the mid-papillary muscle level at baseline and 6 h after occlusion (acute infarction) in eight animals and at baseline and 72 h after occlusion (subacute infarction) in nine animals. Systolic function was assessed by measuring the extent of fractional radial shortening along each of 36 evenly spaced endocardial targets from end-diastole to end-systole; the transmural extent of infarction was determined from the triphenyltetrazolium chloride-staining deficit at 6 and 72 h. The relation between systolic function and transmural extent of infarction was analyzed in two ways. First, the extent of fractional radial shortening in each group was examined as a function of quartile (25%) increments in transmural infarct thickness. This analysis revealed 1) a significant overall loss of fractional radial shortening with increasing transmural extent of infarction in both groups; and 2) significant differences in the extent of systolic dysfunction between successive quartile increments of infarction. Second, the relation between infarct thickness and systolic dysfunction was modeled mathematically by fitting the data from each infarct series to linear, logarithmic and exponential functions.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Contração Miocárdica , Infarto do Miocárdio/fisiopatologia , Processamento de Sinais Assistido por Computador , Sístole , Animais , Cães , Ecocardiografia , Infarto do Miocárdio/diagnóstico , Miocárdio/patologia
17.
J Am Coll Cardiol ; 6(3): 565-71, 1985 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-4031267

RESUMO

Continuous wave Doppler echocardiography has proved useful in detecting and quantitating the high velocity flow disturbances that characterize many stenotic and regurgitant valvular lesions. Pulsed Doppler echocardiography, in contrast, is limited in its ability to quantitate the high velocities that are detected. Recently, new pulsed Doppler systems have been developed that employ high pulse repetition frequencies and can theoretically measure higher flow velocities than those measured by the standard pulsed Doppler systems. To determine the ability of high pulse repetition frequency Doppler echocardiography to accurately measure high velocity flow signals in comparison with the continuous wave method, 80 patients undergoing routine echocardiographic examination for the assessment of valvular heart disease were studied using both techniques. A total of 113 high velocity flow disturbances were detected in 68 patients. In 41 instances, the maximal velocities by the two methods were within 0.5 m/s of each other. In 68 of the 113 high velocity lesions, however, the high pulse repetition frequency technique underestimated the peak velocity found with continuous wave Doppler echocardiography by more than 0.5 m/s. Comparison of the peak velocities recorded by the two methods for the total group showed no significant correlation (r = 0.04, p = NS). Comparison of the difference in peak velocities obtained by the two techniques with the maximal continuous wave velocity (n = 94, r = 0.70, slope = 0.71) suggested that the underestimation becomes greater as the peak velocity increases. Fifteen of the study patients with aortic stenosis subsequently underwent catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Ecocardiografia/métodos , Doenças das Valvas Cardíacas/diagnóstico , Adolescente , Adulto , Idoso , Estenose da Valva Aórtica/diagnóstico , Velocidade do Fluxo Sanguíneo , Cateterismo Cardíaco , Ecocardiografia/instrumentação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
18.
J Am Coll Cardiol ; 24(1): 247-53, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8006273

RESUMO

OBJECTIVES: This study was designed to assess the feasibility of calculating left ventricular volumes using intracardiac ultrasound. BACKGROUND: Previous studies have validated transthoracic echocardiographic determinations of left ventricular volumes and have indicated the superiority of Simpson rule reconstruction algorithms. The feasibility of imaging the left ventricle with intracardiac ultrasound has also been demonstrated. METHODS: The determination of left ventricular volumes with Simpson rule reconstruction of intracardiac ultrasound images was evaluated in two phases. In vitro validation was performed in 29 animal hearts preserved in either a nondistended or distended state. Latex cast volumes were the reference standard. In vivo studies used 14 pigs, and compared intracardiac ultrasound volumes and ejection fraction with single-plane contrast angiographic values. A 12.5-MHz device was used to record short-axis images at 0.5-cm intervals. These were used to reconstruct the ventricle as a stack of cylindric elements using all imaged levels as well as sections recorded every 1 and 2 cm and at a single midventricular level. RESULTS: In the in vitro hearts, when all recorded sections were used, there was excellent agreement between intracardiac ultrasound and latex cast volumes (intracardiac ultrasound volume = 0.89 latex cast volume + 2.22, r = 0.95; intracardiac ultrasound volume = 0.97 latex cast volume + 0.91, r = 0.99) for nondistended and distended hearts, respectively. In vivo, there was again close correspondence between ultrasound and angiographic volumes (intracardiac ultrasound volume = 1.04 angiographic volume - 3.6, r = 0.91). The relation between intracardiac ultrasound and angiographic ejection fraction was fair (intracardiac ultrasound ejection fraction = 1.00 angiographic ejection fraction + 6.85, r = 0.69). Excellent correlations for the volumes were maintained as the number of cross sections was reduced to those recorded every 1 and 2 cm (r = 0.87 to 0.99). With a single midventricular site more variable but generally good correlations were obtained (r = 0.77 to 0.99). CONCLUSIONS: The application of Simpson rule reconstruction to short-axis images of the left ventricle obtained with intracardiac ultrasound provides accurate determination of left ventricular volumes in animal hearts. This technique may prove useful in the analysis of left ventricular structure and function.


Assuntos
Ecocardiografia/métodos , Algoritmos , Animais , Bovinos , Ecocardiografia/instrumentação , Ecocardiografia/estatística & dados numéricos , Estudos de Viabilidade , Ventrículos do Coração/diagnóstico por imagem , Técnicas In Vitro , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Suínos
19.
J Am Coll Cardiol ; 7(6): 1325-34, 1986 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3711490

RESUMO

Two-dimensional echocardiography was employed to define the natural history of regional wall motion abnormalities in a canine model of acute experimental myocardial infarction. Serial short-axis two-dimensional echocardiograms were recorded in 11 closed chest dogs before coronary occlusion and 10, 30, 60, 180 and 360 minutes after permanent coronary ligation. Radiolabeled microsphere-derived blood flows were obtained in each study period and the histochemical (triphenyltetrazolium chloride) extent of infarction was determined at 6 hours. Previously published methods were used to quantitate field by field (every 16.7 ms) excursion of 36 evenly spaced endocardial targets. The circumferential extent of abnormal wall motion was followed sequentially using previously published definitions of abnormality: 1) systolic fractional radial change of less than 20%; 2) dyskinesia (systolic bulging) at the point in time (echocardiographic field) in which there is maximal dyskinesia; and 3) correlation with composite normal ray motion falling outside the 95% confidence limits defined in the control period. On the basis of the triphenyltetrazolium chloride staining pattern, the ventricle was divided into five zones: central infarct zone, zone with greater than 25% transmural infarction, total infarct zone, border zones and normal zone. Mean systolic fractional radial change was calculated for each zone and used as an index of the magnitude of abnormal wall motion. Regardless of the definition of abnormality employed, the circumferential extent of abnormal wall motion manifested at 10 minutes after occlusion did not significantly change, even up to 6 hours later. Similarly, 10 minutes after coronary occlusion the three infarct zones and border zones demonstrated significantly reduced systolic fractional radial change. This remained stable over the remainder of the 6 hour study period. It is concluded that once established at 10 minutes after coronary occlusion, the circumferential extent and magnitude of abnormal wall motion do not significantly change in the immediate postinfarct (6 hour) period.


Assuntos
Coração/fisiopatologia , Contração Miocárdica , Infarto do Miocárdio/fisiopatologia , Animais , Cães , Ecocardiografia , Ventrículos do Coração/fisiopatologia , Fatores de Tempo
20.
J Am Coll Cardiol ; 8(4): 819-29, 1986 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3760355

RESUMO

A new technique for quantitatively mapping the three-dimensional left ventricular endocardial surface was developed, using measurements from standard cross-sectional echocardiographic images. To validate the accuracy of this echocardiographic mapping technique in an animal model, the endocardial areas of 15 excised canine ventricles were calculated using measurements made from echocardiographic studies of the hearts and compared with areas determined with latex casts of the same ventricles. Close correlation (r = 0.87, p less than 0.001) between these two measures of endocardial area provided preliminary confirmation of the accuracy of the maps. To further characterize the mapping algorithm, it was translated into computer format and used to map the surfaces of idealized hemiellipsoids. Areas measured with this mapping technique closely approximated the actual areas of idealized surfaces with a wide spectrum of shapes; maps were particularly accurate for ellipsoids with shapes similar to those of undistorted human ventricles. Also, the accuracies of area calculations were relatively insensitive to deviation from the assumed positions of the echocardiographic short-axis planes. Finally, although the accuracy of the mapping technique improved as data from more transverse planes were added, the procedure proved reliable for estimating surface areas when data from only three planes were used. These studies confirm the accuracy of the echocardiographic mapping technique, and they suggest that the resulting planar plots might be useful as templates for localizing and quantifying the overall extent of abnormal wall motion.


Assuntos
Ecocardiografia , Endocárdio/anatomia & histologia , Animais , Cães , Ventrículos do Coração/anatomia & histologia , Software
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