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Biomedical subjects

N Bom

Publications and source records attributed to N Bom.

At least 109 records · Page 6Linked to original sources
PubMed1985

Vaporization of atherosclerotic plaques by spark erosion.

An alternative to the laser irradiation of atherosclerotic lesions has been developed. A pulsed electrocardiogram R wave-triggered electrical spark erosion technique is described. Controlled vaporization of fibrous and lipid plaques with minimal thermal side effects was achieved and documented histologically in vitro from 30 atherosclerotic segments of six human aortic autopsy specimens. Craters with a constant area and a depth that varied according to the duration of application were produced. The method was confirmed to be electrically safe during preliminary in vivo trials in the coronary arteries of seven anesthetized pigs. The main advantages of this technique are that it is simpler to execute than laser irradiation and potentially more controllable.

Aged↗
PubMed1984

Variability in the time interval between tricuspid and mitral valve closure in Ebstein's anomaly.

The time interval between mitral and tricuspid valve closure was measured from M-mode echocardiograms in patients with Ebstein's anomaly. It was found that this time interval demonstrated a range of values within each patient. The use of different transducer positions on the chest wall was found to be the predominant factor. There was no correlation between the measured time interval, its variability, and the moment of measurement during breathing. However, a period of breathholding significantly reduced the variability. This study indicates that a wide range of time intervals might be measured in a single patient. We conclude therefore, that this parameter should be used with great care in the diagnosis of Ebstein's anomaly.

Ebstein Anomaly↗
PubMed1984

Acute effect of maternal smoking on the maternal and fetal cardiovascular system.

Maternal and fetal cardiovascular dynamics were studied in relation to maternal smoking in 18 healthy nulliparous subjects randomly divided into a smoking (n = 9) and a control group (n = 9) between 34 and 38 weeks of gestation. At the end of the study, data from 7 smokers and 7 controls were available for analysis. A significant rise in maternal heart rate and systolic blood pressure was observed during and following smoking one cigarette. A significant increase in fetal heart rate occurred following smoking, whereas mean blood flow velocity and vessel diameter in the fetal descending aorta as measured by pulsed Doppler and time motion techniques did not demonstrate any significant changes.

Aorta↗
PubMed1983

Comparison of internal diameter of great arteries in congenital heart disease. A cross-sectional echocardiographic study.

Cross-sectional echocardiographic studies were used to measure and compare the internal diameter of both aortic root and pulmonary artery in 104 patients with normally related great arteries. Six groups of patients were assessed: normal, with an intracardiac shunt, with tetralogy of Fallot, with pulmonary stenosis, with aortic stenosis, and with atresia of the right atrioventricular valve orifice. In addition, a postmortem study was carried out in normal heart specimens and in specimens with an atrioventricular septal defect. It appeared that the echocardiographically studied ratio between the aortic and pulmonary artery diameter varied considerably. In normal subjects the pulmonary artery diameter tends to be slightly larger than the aortic root diameter: this observation was confirmed by the postmortem data. In other instances the pulmonary artery diameter appeared to be smaller than the aortic root diameter, for example patients with tetralogy of Fallot and those with tricuspid atresia, whereas the reverse was noted in patients with an intracardiac shunt. This two dimensional study has shown that functional adaptations of the calibre of the great arteries can be measured and identified in patients with congenital heart disease.

Adolescent↗
PubMed1983

Echography.

Explore the source record for details and available documents.

Echocardiography↗
PubMed1982

The microcomputer in medical instrumentation. Aspects of an automated monitoring system.

The major technical trends in medical computing include sensor devices and artificial intelligence techniques. Use of the computer will render instruments more accessible and make them friendlier to the user. Examples include automation of gain setting in echocardiology and instant computation of M-mode data. In intensive care units, computers have become an integral part of patient monitoring over the last two decades. Third generation microcomputer-based systems are presently helping to solve many earlier problems. Features such as touch-sensitive keys or screens (eliminating keyboards) and integrated front-end are greatly increasing user acceptance. A new monitoring system developed at the Thorax Center for intensive cardiac patient monitoring and provided with these features will be described.

Computers↗
PubMed1976

Resolution problems in echocardiology: a source of interpretation errors.

Resolution is the ability of the echocardiographic system to distinguish closely lying structures. This is usually defined in two directions: laterally (lateral resolution) and in depth (axial resolution). With use of short ultrasonic pulses, axial resolution is not a major problem. By far the more important problem is the limited lateral resolution that results from the finite beam width of current ultrasonic devices. This results in the display of echoes that originate from off-axis structures. How these off-axis or "spurious echoes" affect the display is a function of the way the echographic information is handled. In conventional M-mode tracings, spurious echoes are displayed at a site where there is no directly corresponding anatomic structure, whereas with two-dimensional imaging, these echoes may result in important distortions of structures. The underlying principles are illustrated by a clinical experiment wherein the ball of a Starr-Edwards mitral valve prosthesis serves as a target of known shape and dimensions. These data are used to elucidate some of the problems and potential errors encountered in the interpretation of clinical M-mode recordings of the aorta, mitral valve and the left ventricular endocardium as well as their cross-sectional analysis. They also explain the present limitations of quantification of left ventricular performance from cross-sectional images.

Aorta↗
PubMed1975

[Bidimensional and direct visualization of the heart by multiple element echocardiography].

Multiple element echography permits a direct visualization of heart sections. In congenital heart diseases, an accurate anatomical diagnosis is often possible. In valvular heart diseases, visualization of the valvular movements and measurement of haemodynamic repercussions over the other cardiac structures makes it possible to assess the severity of the lesion. The overall function of the heart may also be assessed as well on the basis of measurement of the size of the heart, and above all through analysis of valvular movements and the left ventricular wall kinaetics, an information analogous to that obtained by cineangiocardiography. A quantitative study of the left ventricular function by measurement of the systolic and diastolic volumes is still in the experimental stage. A different method of recording and the use of a large single cristal allow a better resolution of the picture of conventional echography, but technical progress might be foreseen in multiple element echography.

Child↗