Objective-A normal fetal flow velocity profile through the atrioventricular valves early in gestation is characterised by a higher late peak (A) than early peak (E) velocity waveform, whereas the E/A ratio is known to increase throughout pregnancy. This study aims firstly to identify which of the two variables, E or A, is the contributory factor to the increased E/A ratio and secondly to assess the relative influence of gestational age, heart rate, and stroke volume on the flow velocity profile through the fetal mitral valve. Design-Eighty normal fetuses from 18 to 38 weeks of gestation were examined by Doppler echocardiography. The variables measured were E and A waves, the early and late flow velocity integrals (EI and AI), and the total filling velocity integral (TI). The ratios E/A and EI/AI were also calculated. Transvalvar flow was obtained by multiplying TI by mitral area. Associations between Doppler variables and gestational age, heart rate, and stroke volume were assessed by multifactorial Anova and simple or multiple stepwise regression analyses. Results-The results showed that the heart rates found did not affect flow velocity variables. There were only weak correlations between both A and AI values and gestational age (negative) and volume load (positive). With the advance in gestation, a significant increase in the early filling E -wave was found. The E wave was also positively correlated with stroke volume. what is normally found during extrauterine life, the fetal profile is characterised by a higher last peak (A) than early peak (E) velocity waveform. This waveform has been interpreted as an indication of a decrease in compliance of the fetal myocardium. With advancing gestational age, the fetal ratio E/A has been shown to increase progressively which has been interpreted as an improvement in myocardial compliance.2 Doppler derived indices of left ventricular function, however, are complex phenomena affected by the interaction of multiple factors." Whereas the E wave is related to active ventricular muscle relaxation, the A wave is caused by atrial contraction and also influenced by ventricular compliance. The respective velocity profiles of the E and A waves are interrelated with each other. It is theoretically possible that during fetal life, an inadequate myocardial relaxation could impair early ventricular filling thereby allowing more blood to remain in the atrium for the last part of diastole, which would result in a higher A wave. This event would not necessarily be due primarily to a lack of myocardial compliance. Furthermore, in adult life other variables such as heart rate and loading conditions are known to influence the relation between the two ventricular diastolic filling waves independently of muscular diastolic function. Attention has not been given to the influence of these variables on fetal myocardial diastolic function. ConclusionIt is the purpose of this study therefore, firstly to find which of the two elements of left ventricular filling dynamics, the E or A wave, ...

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Background During early childhood, in particular, there is a continuum between tuberculosis infection and disease. When establishing the diagnosis in a child with suspected tuberculosis, the distinction between infection and disease frequently depends on the interpretation of the chest X-ray. Some studies have shown hilar and mediastinal lymphadenopathies on computed tomography (CT) in children with tuberculosis infection without apparent disease, i.e., asymptomatic children with a positive tuberculin skin test and normal chest X-ray. These observations raise the issue of whether pulmonary CT should be performed in children with tuberculosis infection without apparent disease and whether different types of therapy should be administered depending on the results. Methods We reviewed the physiopathology of tuberculosis infection and disease, diagnostic methods and treatment, and the literature on the use of pulmonary CT scan in pediatric tuberculosis. Results Modern CT scanners indicate hilar and mediastinal lymphadenopathies in many of the children with tuberculosis infection with no apparent disease on chest X-rays. However, neither the size nor the morphology of these adenopathies allows active tuberculosis to be diagnosed. The natural history of childhood tuberculosis indicates that most children show hilar lymphadenopathies after the primary infection, although progression to disease is rare and is characterized by the presence of clinical symptoms. The exceptions are children younger than 4 years old and those with immune alterations who more frequently show progression of infection to disease and who require close follow-up. In addition, the experience accumulated over many years in the treatment of tuberculosis infection with isoniazid has shown this drug to be effective in both short-and long-term prevention of active disease. Official guidelines and expert opinion do not recommend systematic pulmonary CT scan in these children or modification of treatment according to the results. Conclusions Hilar and mediastinal lymph nodes are frequently found in the CT scans of children with tuberculosis infection without apparent disease but there is no evidence that these adenopathies indicate active disease or that these children require different treatment. Consequently, until demonstrated otherwise, pulmonary CT scanning and changes in chemoprophylaxis are not justified in children with tuberculosis infection.