Influence of left ventricular size and hemodynamics on the systolic longitudinal myocardial Doppler velocity response to stress

Background Systolic myocardial Doppler velocity accurately identifies coronary artery disease. However, these velocities may be affected by age, hemodynamic responses to stress, and left ventricular cavity size. We sought to examine the influences of these variables on myocardial velocity during dobutamine stress in patients with normal wall motion. Methods One hundred seventy-nine consecutive patients with normal dobutamine echocardiograms were studied. Color myocardial tissue Doppler data were obtained at rest and peak stress, and peak systolic myocardial velocity (PSV) was measured in all basal and midventricular segments. Velocities at rest and peak stress were compared with left ventricular diastolic and systolic volumes, blood pressure, heart rate, and age by Pearson correlation and interdecile analysis by use of analysis of variance. Results The only clinical variable correlating with velocity was age; PSV showed only mild correlation with age at rest (r(2) = 0.01, P = .001) and peak stress (r(2) = 0.02, P = .001), but the normal peak velocity was significantly different between the extremes of age (<44 years and >74 years). There was very weak correlation of PSV with systolic and diastolic blood pressure (r(2) < 0.01), heart rate (r(2) < 0.01), systemic vascular resistance (r(2) = 0.08), and left ventricular volumes (r(2) < 0.01). Conclusions Peak systolic velocity during dobutamine stress is relatively independent of hemodynamic factors and left ventricular cavity size. The extremes of age may influence peak systolic Doppler velocities. These results suggest that peak systolic velocity may be a robust quantitative measure during dobutamine echocardiography across most patient subgroups.

Usefulness of myocardial tissue Doppler echocardiography to evaluate left ventricular dyssynchrony before and after biventricular pacing in patients with idiopathic dilated cardiomyopathy

Tissue Doppler imaging allows assessment of left ventricular dyssynchrony and resynchronization after biventricular pacing.

Ambulatory blood pressure and Doppler echocardiographic indexes of borderline hypertensive men presenting an exaggerated blood pressure response during dynamic exercise

Borderline hypertension (BH) has been associated with an exaggerated blood pressure (BP) response during laboratory stressors. However, the incidence of target organ damage in this condition and its relation to BP hyperreactivity is an unsettled issue. Thus, we assessed the Doppler echocardiographic profile of a group of BH men (N = 36) according to office BP measurements with exaggerated BP in the cycloergometric test. A group of normotensive men (NT, N = 36) with a normal BP response during the cycloergometric test was used as control. To assess vascular function and reactivity, all subjects were submitted to the cold pressor test. Before Doppler echocardiography, the BP profile of all subjects was evaluated by 24-h ambulatory BP monitoring. All subjects from the NT group presented normal monitored levels of BP. In contrast, 19 subjects from the original BH group presented normal monitored BP levels and 17 presented elevated monitored BP levels. In the NT group all Doppler echocardiographic indexes were normal. All subjects from the original BH group presented normal left ventricular mass and geometrical pattern. However, in the subjects with elevated monitored BP levels, fractional shortening was greater, isovolumetric relaxation time longer, and early to late flow velocity ratio was reduced in relation to subjects from the original BH group with normal monitored BP levels (P<0.05). These subjects also presented an exaggerated BP response during the cold pressor test. These results support the notion of an integrated pattern of cardiac and vascular adaptation during the development of hypertension.

Verificação de fórmulas para a evolução da erosão em taludes de quebra-mares

Os quebra-mares de taludes são estruturas de protecção portuária muito comuns em Portugal e em cujo projecto se assume a necessidade de obras de manutenção ou reparação durante a sua vida útil. Para a avaliação da necessidade de realização destas obras, é necessária a existência de um programa de acompanhamento da estrutura contemplando a medição de grandezas relevantes para essa avaliação. Uma destas grandezas é o volume erodido do manto protector por acção da agitação marítima, que pode determinar-se a partir de levantamentos consecutivos da envolvente dos taludes e com o qual se pode definir o dano da estrutura. Melby (1999) apresentou uma fórmula para previsão da evolução do dano em quebra-mares de taludes com base nas características da agitação neles incidente. Nesta dissertação apresentam-se os resultados do trabalho realizado com o objectivo de avaliar a aplicabilidade daquela fórmula em condições de agitação diferentes das consideradas por aquele autor. De modo a atingir esse objectivo reproduziram-se as experiências descritas por Melby (1999). Tratam-se de ensaios de longa duração em modelo Físico reduzido em que sequências de estados de agitação estacionários vão atingindo o manto protector e se mede a área erodida no final da actuação de cada estado de agitação. Uma vez que estes ensaios terminam apenas quando fica visível uma porção apreciável do filtro sob o manto protector, a sua duração é substancialmente superior à dos ensaios comuns de estabilidade e galgamentos deste tipo de estrutura. A medição da área erodida no final da actuação de cada estado de agitação foi realizada a partir da reconstrução de pares estereoscópicos de fotografias em que a refracção induzida pela interface ar-água é corrigida. Tal significa que aquelas fotografias podem ser tiradas mantendo-se a água no canal. Pretendeu-se com a utilização desta técnica de levantamento avaliar a sua operacionalidade em ensaios de longa duração, para os quais seja necessário o levantamento exaustivo de perfis.

Pelos mares da leitura literária no ensino superior: há lugar(es) para/do livro na era digital?

É consensualmente reconhecida na atualidade a relevância da leitura na sociedade, abrindo-se, de forma crescente, a uma multiplicidade de dimensões alimentadas pela comunicação em rede. No ensino superior, tais dimensões merecem particular atenção, não só pelos desafios lançados pelo seu caráter cada vez mais diversificado, como pelas possíveis consequências que daí podem advir para o futuro profissional dos estudantes. Assim, nesta comunicação temos como objetivo indagar a importância do livro na era digital enquanto possível suporte configurador de práticas de leitura literária de estudantes do ensino superior a frequentar um 1.º Ciclo de estudos de Bolonha. No que se refere à metodologia adotada, face aos objetivos do estudo, considerámos adequada uma abordagem de natureza qualitativa, tendo como referencial metodológico o estudo de caso. Os participantes foram 27 estudantes inscritos na unidade curricular de Iniciação à Leitura e à Escrita que integra o plano de estudos da licenciatura em Educação Básica, na Escola Superior de Educação de Viseu (3.º ano, 1.º semestre, ano letivo 2015-2016). Os instrumentos utilizados foram 27 reflexões escritas individuais realizadas no âmbito do trabalho autónomo dos estudantes. A técnica privilegiada foi a análise de conteúdo. Apesar dos amplos itinerários de leitura proporcionados pela era digital, conclui-se que os estudantes atribuem grande importância ao livro impresso enquanto potenciador da motivação para a leitura literária, relegando para segundo plano possíveis vantagens do livro em suporte digital. Embora a tecnologia seja omnipresente no seu quotidiano, é o livro que resguarda os lugares das memórias que se entretecem nos seus percursos de leitura.

Endocardite infecciosa e acidente vascular cerebral: mecanismos fisiopatológicos e avaliação ultrassonográfica

Uma das mais graves complicações da endocardite infecciosa é o acidente vascular cerebral isquémico, responsável por uma alta taxa de mortalidade e morbilidade nos países desenvolvidos. Embora não seja o mecanismo dominante, o cardioembolismo é responsável por cerca de 20% dos enfartes cerebrais isquémicos. Sabe-se que o embolismo cerebral afeta mais de 40% dos pacientes com endocardite infecciosa, uma vez que a embolização da vegetação resultante da infeção das estruturas intracardíacas para a circulação arterial pode levar à oclusão das artérias cerebrais, dando origem, assim, a enfarte por ausência de aporte sanguíneo. O desenvolvimento de técnicas não invasivas baseadas na ultrassonografia tem potenciado um amplo estudo destas patologias, quer a nível cardíaco, quer vascular, promovendo uma melhor compreensão dos mecanismos fisiopatológicos que as envolvem. A ecocardiografia e o Doppler transcraniano detêm um papel central, respetivamente, no diagnóstico e predição do risco de fenómenos embólicos em pacientes com endocardite infecciosa e na avaliação inicial, prognóstico e follow-up de um episódio de acidente vascular cerebral.

Avaliação da função diastólica no ventrículo esquerdo em mulheres hipertensas com excesso de peso ou obesidade

Mestrado em Tecnologia de Diagnóstico e Intervenção Cardiovascular - Ramo de especialização: Ultrassonografia Cardiovascular

Utilização de técnicas de análise fotogramétricas em quebra-mares de taludes

Dissertação de Natureza Científica elaborada no Laboratório Nacional de Engenharia Civil (LNEC) para obtenção do grau de mestre em Engenharia Civil na Área de Especialização de Hidráulica no âmbito do protocolo de cooperação entre o ISEL e o LNEC

Upper Arm Measurements of Healthy Neonates Comparing Ultrasonography and Anthropometric Methods

Objective: To compare measurements of the upper arm cross-sectional areas (total arm area,arm muscle area, and arm fat area of healthy neonates) as calculated using anthropometry with the values obtained by ultrasonography. Materials and methods: This study was performed on 60 consecutively born healthy neonates: gestational age (mean6SD) 39.661.2 weeks, birth weight 3287.16307.7 g, 27 males (45%) and 33 females (55%). Mid-arm circumference and tricipital skinfold thickness measurements were taken on the left upper mid-arm according to the conventional anthropometric method to calculate total arm area, arm muscle area and arm fat area. The ultrasound evaluation was performed at the same arm location using a Toshiba sonolayer SSA-250AÒ, which allows the calculation of the total arm area, arm muscle area and arm fat area by the number of pixels enclosed in the plotted areas. Statistical analysis: whenever appropriate, parametric and non-parametric tests were used in order to compare measurements of paired samples and of groups of samples. Results: No significant differences between males and females were found in any evaluated measurements, estimated either by anthropometry or by ultrasound. Also the median of total arm area did not differ significantly with either method (P50.337). Although there is evidence of concordance of the total arm area measurements (r50.68, 95% CI: 0.55–0.77) the two methods of measurement differed for arm muscle area and arm fat area. The estimated median of measurements by ultrasound for arm muscle area were significantly lower than those estimated by the anthropometric method, which differed by as much as 111% (P,0.001). The estimated median ultrasound measurement of the arm fat was higher than the anthropometric arm fat area by as much as 31% (P,0.001). Conclusion: Compared with ultrasound measurements using skinfold measurements and mid-arm circumference without further correction may lead to overestimation of the cross-sectional area of muscle and underestimation of the cross-sectional fat area. The correlation between the two methods could be interpreted as an indication for further search of correction factors in the equations.

Prevalência de Doença Carotídea na Patologia Cérebro-Vascular Isquémica. O Papel do Eco-Doppler

BACKGROUND: Atherosclerotic carotid disease represents approximately 20% of the causes of ischemic stroke. Effective treatment options, such as endovascular or surgical revascularization procedures, are available. Doppler Ultrasound (DUS) is a non-invasive, inexpensive, routine exam used to evaluate the presence of internal carotid artery (ICA) stenosis. We retrospectively analysed the prevalence of severe atherosclerotic carotid disease in a population of patients with acute ischemic stroke/transitory ischemic attacks (TIAs), and the role of DUS in the detection of ICA stenosis and treatment decisions in these patients. METHODS: A total of 318 patients with ischemic stroke or TIAs was admitted to our stroke unit, and 260 patients were studied by DUS. ICA stenosis was evaluated by DUS according to peak systolic velocity. All DUS exams were performed by the same operator. ICA stenosis was further assessed in 43 patients by digital subtraction angiography (DSA) using NASCET criteria. RESULTS: Of the total 318 patients, 260 (82%) had DUS evaluation. Of the total 520 ICAs studied by DUS, degrees of ICA stenosis were: 0-29% n= 438 (84%); 30-49% n= 8 (2%); 50-69% n= 27 (5%); 70-89% n= 15 (3%); 90-99% n= 20 (4%); oclusão n= 14 (2%). Of the total 260 patients studied, 43 (16.5%) underwent DSA. Sensibility and specificity of DUS in the diagnosis of carotid stenosis over 70% were, respectively, 91% e 84%. Of the total 31 patients with significant carotid stenosis (70-99%), 23 (74%) underwent subsequent carotid revascularization procedures. DISCUSSION: DUS is an important screening test in our stroke unit, justifying its use as a routine exam for all patients with ischemic stroke/TIAs. Moreover, our results show the relevance of severe carotid disease in a population with acute ischemic stroke/TIAs (16.5%), with a total of 9% of patients being submitted to carotid revascularization procedures.

Utilidade do Doppler Tecidular na Predição de Eventos Arrítmicos em Adultos com Tetralogia de Fallot Corrigida

INTRODUCTION: Adults with repaired tetralogy of Fallot (TOF) may be at risk for progressive right ventricular (RV) dilatation and dysfunction, which is commonly associated with arrhythmic events. In frequently volume-overloaded patients with congenital heart disease, tissue Doppler imaging (TDI) is particularly useful for assessing RV function. However, it is not known whether RV TDI can predict outcome in this population. OBJECTIVE: To evaluate whether RV TDI parameters are associated with supraventricular arrhythmic events in adults with repaired TOF. METHODS: We studied 40 consecutive patients with repaired TOF (mean age 35 +/- 11 years, 62% male) referred for routine echocardiographic exam between 2007 and 2008. The following echocardiographic measurements were obtained: left ventricular (LV) ejection fraction, LV end-systolic volume, LV end-diastolic volume, RV fractional area change, RV end-systolic area, RV end-diastolic area, left and right atrial volumes, mitral E and A velocities, RV myocardial performance index (Tei index), tricuspid annular plane systolic excursion (TAPSE), myocardial isovolumic acceleration (IVA), pulmonary regurgitation color flow area, TDI basal lateral, septal and RV lateral peak diastolic and systolic annular velocities (E' 1, A' 1, S' 1, E' s, A' s, S' s, E' rv, A' rv, S' rv), strain, strain rate and tissue tracking of the same segments. QRS duration on resting ECG, total duration of Bruce treadmill exercise stress test and presence of exercise-induced arrhythmias were also analyzed. The patients were subsequently divided into two groups: Group 1--12 patients with previous documented supraventricular arrhythmias (atrial tachycardia, fibrillation or flutter) and Group 2 (control group)--28 patients with no previous arrhythmic events. Univariate and multivariate analysis was used to assess the statistical association between the studied parameters and arrhythmic events. RESULTS: Patients with previous events were older (41 +/- 14 vs. 31 +/- 6 years, p = 0.005), had wider QRS (173 +/- 20 vs. 140 +/- 32 ms, p = 0.01) and lower maximum heart rate on treadmill stress testing (69 +/- 35 vs. 92 +/- 9%, p = 0.03). All patients were in NYHA class I or II. Clinical characteristics including age at corrective surgery, previous palliative surgery and residual defects did not differ significantly between the two groups. Left and right cardiac chamber dimensions and ventricular and valvular function as evaluated by conventional Doppler parameters were also not significantly different. Right ventricular strain and strain rate were similar between the groups. However, right ventricular myocardial TDI systolic (Sa: 5.4+2 vs. 8.5 +/- 3, p = 0.004) and diastolic indices and velocities (Ea, Aa, septal E/Ea, and RV free wall tissue tracking) were significantly reduced in patients with arrhythmias compared to the control group. Multivariate linear regression analysis identified RV early diastolic velocity as the sole variable independently associated with arrhythmic history (RV Ea: 4.5 +/- 1 vs. 6.7 +/- 2 cm/s, p = 0.01). A cut-off for RV Ea of < 6.1 cm/s identified patients in the arrhythmic group with 86% sensitivity and 59% specificity (AUC = 0.8). CONCLUSIONS: Our results suggest that TDI may detect RV dysfunction in patients with apparently normal function as assessed by conventional echocardiographic parameters. Reduction in RV early diastolic velocity appears to be an early abnormality and is associated with occurrence of arrhythmic events. TDI may be useful in risk stratification of patients with repaired tetralogy of Fallot.

Importância Prognóstica do Doppler Tecidular nos Doentes com Miocardiopatia Dilatada

Previous studies have shown that a ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/E') of > 15, obtained by tissue Doppler imaging (TDI), correlates with left ventricular filling pressure. OBJECTIVE: The aim of our study was to assess whether E/E' provides prognostic information in patients with dilated cardiomyopathy. METHODS: We studied 33 patients with dilated cardiomyopathy and mean ejection fraction of 31%. All the patients underwent routine two-dimensional and Doppler echocardiographic examination and TDI to determine early peak velocity of the mitral annulus. Pro-B-type natriuretic peptide (pro-BNP) and peak oxygen consumption (VO2max) were also measured. Patients were divided into two groups according to the value of E/E': Group I (n = 15 patients) with E/E' > or = 15 and Group II (n = 18 patients) with E/E' < 15. Patients were followed for 12+/-4 months; new hospital admission due to heart failure, heart transplantation and death were considered as cardiac events. RESULTS: There were significant differences between the two groups in conventional two-dimensional echocardiographic measurements (dimensions and ejection fraction) and Doppler parameters (mitral inflow). With regard to mitral annular velocities obtained by TDI at two different points (septum and lateral wall), the E', A' and S' velocities differed significantly between the two groups, with lower velocities in Group I. Systolic velocity measured in the lateral portion of the mitral annulus showed the most significant difference: Group I - 4.46 cm/sec versus Group II - 7.19 cm/sec, p < 0.00001. Pro-BNP was 5622 pg/ml in Group I, and 1254 pg/ml in Group II, p = 0.004. VO2 max was significantly different between the two groups: Group I - 17.6 ml/kg/min versus Group II - 22.8 ml/kg/min, p = 0.004. During follow-up, events were more common in Group I, with 9 patients (60%) having events, while in Group II, the event rate was 11.1% (2 patients), p = 0.004. CONCLUSION: The ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus is a powerful predictor of clinical outcome. Lower velocities of mitral annulus on TDI are expected in patients with E/E' > or = 15. Systolic velocities of under 5 cm/sec measured in the lateral portion of the mitral annulus appeared to be strongly related to prognosis.

As Alterações do Doppler Cardíaco Perante Modificação da Volémia em Cuidados Intensivos Polivalentes

Num grupo de 64 doentes de uma Unidade de Cuidados Intensivos, 24 dos quais submetidos a ventilação mecânica, foi determinada a influência da modificação da volémia nas características do Doppler cardíaco, através da negativização do balanço hídrico e correspondente modificação da pressão venosa central. Com a modificação da volémia, a relação E/A do fluxo transvalvular mitral mostrou uma tendência para reduzir, o tempo de desaceleração da onda E mitral para diminuir, o tempo de relaxamento isovolumétrico para aumentar, e a veia cava inferior reduziu o seu diâmetro expiratório e aumentou o valor do colapso inspiratório. Não se observou uma correlação significativa entre os valores das variáveis estudadas e a modificação da volémia, inclusivamente entre a pressão venosa central e o balanço hídrico. A modificação da volémia em doentes críticos modifica as características de determinados parâmetros de ecocardiografia- -Doppler, mas não é possível predizer a magnitude dessa variação.

O Eco-Doppler na Dissecção da Aorta Abdominal

Apresenta-se um caso clínico de dissecção da aorta abdominal - tipo B - diagnosticada por eco-Doppler e tomografia axial computorizada (TC). Discute-se o interesse do eco-Doppler no diagnóstico de dissecção da aorta abdominal e na avaliação do envolvimento arterial visceral. É ainda um método útil no follow-up dos doentes com terapêutica conservadora.