Biomedical subjects

H De Raedt

Publications and source records attributed to H De Raedt.

15 recordsLinked to original sources

PubMed2004

[Practical considerations for the treatment of acute rhythm disturbances. Report of Belgium Interdisciplinary Working Group on Acute Cardiology].

Acute arrhythmia is a condition covering a wide variety of rhythm disturbances. The aim of the article is to give practical recommendations for the approach and the treatment of the patient presenting with an acute arrhythmia. We discuss bradycardia and tachycardia. Tachycardias are divided into the small QRS complex tachycardias and the wide QRS complex tachycardias. Another important distinction with immediate therapeutic consequences is that between the hemodynamic stable and unstable patient. Flowcharts with diagnostic means and therapeutic schemes are added and a table with practical considerations for electrical cardioversion.

Acute Disease↗

PubMed2003

One-step finite-difference time-domain algorithm to solve the Maxwell equations.

We present a one-step algorithm to solve the time-dependent Maxwell equations for systems with spatially varying permittivity and permeability. We compare the results of this algorithm with those obtained from the Yee algorithm and from unconditionally stable algorithms. We demonstrate that for a range of applications the one-step algorithm may be orders of magnitude more efficient than multiple time-step, finite-difference time-domain algorithms. We discuss both the virtues and limitations of this one-step approach.

Journal Article↗

PubMed2002

Higher-order unconditionally stable algorithms to solve the time-dependent Maxwell equations.

For the recently introduced algorithms to solve the time-dependent Maxwell equations [J. S. Kole, M. T. Figge, and H. De Raedt, Phys. Rev. E 64, 066705 (2001)], we construct a variable grid implementation and an improved spatial discretization implementation that preserve the exceptional property of the algorithms to be unconditionally stable by construction. We find that the performance and accuracy of the corresponding algorithms are significant and illustrate their practical relevance by simulating various physical model systems.

Journal Article↗

PubMed2002

[Recommendations for the management of acute chest pain. Report of the Belgian Interdisciplinary Group on Acute Cardiology].

The Belgium Interdisciplinary Working Group on Acute Cardiology (BIWAC), including cardiologists, intensivists and urgentists was formed to give consensus regarding the management of acute chest pain in the prehospital and the early hospital phases. General recommendations and critical pathways are proposed to improve the treatment of the patients with acute coronary syndromes.

Acute Disease↗

PubMed2002

[Recommendations for management of acute chest pain. Report of the Belgium Interdisciplinary Working Group on Acute Cardiology].

The Belgium Interdisciplinary Working group on Acute Cardiology, including cardiologists, intensivists and urgentists was formed to provide consensus regarding the management of acute chest pain in the prehospital and the early hospital phase. General recommendations and critical pathways are proposed to improve the treatment of the patients with acute coronary syndromes.

Acute Disease↗

PubMed2001

Unconditionally stable algorithms to solve the time-dependent Maxwell equations.

Based on the Suzuki product-formula approach, we construct a family of unconditionally stable algorithms to solve the time-dependent Maxwell equations. We describe a practical implementation of these algorithms for one-, two-, and three-dimensional systems with spatially varying permittivity and permeability. The salient features of the algorithms are illustrated by computing selected eigenmodes and the full density of states of one-, two-, and three-dimensional models and by simulating the propagation of light in slabs of photonic band-gap materials.

Journal Article↗

PubMed2001

Quantum Monte Carlo method for attractive Coulomb potentials.

Starting from an exact lower bound on the imaginary-time propagator, we present a path-integral quantum Monte Carlo method that can handle singular attractive potentials. We illustrate the basic ideas of this quantum Monte Carlo algorithm by simulating the ground state of hydrogen and helium.

Journal Article↗

PubMed2001

Blurred vision, left bundle-branch block and cardiac failure.

We cared for a patient with progressive renal impairment who presented with blurred vision, QRS broadening and cardiac failure due to chronic cibenzoline intoxication. Treatment consisted of catecholamines and repetitive infusions of Ringer lactate. Cardiac function and symptoms recovered completely.

Aged↗

PubMed2001

An unusual case of biventricular cardiac failure.

We present a patient with acute retrosternal pain and dyspnoea. Clinical examination revealed a woman in shock with a loud holosystolic murmur and congested jugular veins. Echocardiography showed severe mitral insufficiency. At transoesophageal echocardiography a large mass was seen in the right atrium. The differential diagnosis was a thrombus or an intracardiac tumour. Subsequent histology revealed a non-Hodgkin lymphoma in the right atrium, the wall of the left atrium extending to the mitral valve and further location in the pelvis and duodenum. The discussion incorporates a brief overview of the literature.

Aged↗

PubMed2000

Morphological image analysis of quantum motion in billiards.

Morphological image analysis is applied to the time evolution of the probability distribution of a quantum particle moving in two- and three-dimensional billiards. It is shown that the time-averaged Euler characteristic of the probability distribution provides a well defined quantity to distinguish between classically integrable and nonintegrable billiards. In three dimensions the time-averaged mean breadth of the probability distribution may also be used for this purpose.

Journal Article↗

PubMed1998

Shoshin syndrome: two case reports representing opposite ends of the same disease spectrum.

Thiamine deficiency can have cardiovascular and neurological manifestations. Cardiac beriberi is classically thought to represent a high-output state with oliguria and lactic acidosis. The condition can, however, also present itself with a low cardiac output and fulminant vascular collapse, or as an acute fatal form, causing sudden death, without clear-cut signs of cardiomegaly. In the western society beriberi is mainly encountered in alcoholics. We report on two cases, one with high-output failure and the other with low-output failure and cardiovascular collapse. In both patients the diagnosis of shoshin syndrome was made, and and both showed a spectacular improvement of congestive heart failure symptoms after treatment with thiamine. A therapeutic trial with thiamine is the only way to rapid diagnosis.

Adult↗

PubMed1997

Computer simulation of time-gated transillumination and reflection of biological tissues and tissuelike phantoms.

A simulation technique is employed to explore the possibility of locating millimeter-sized objects, immersed in turbid media, from time-gated measurements of the transmitted or reflected light. The simulation results for tissuelike phantoms are compared to experimental transillumination data and excellent agreement is found. Simulations of time-gated reflection experiments show that it is possible to detect objects of 1 mm diameter. This may open new possibilities for medical diagnosis of breast cancer in an early stage.

Algorithms↗

PubMed1997

Importance of volume factors in dialysis related hypertension.

OBJECTIVE: To evaluate the relation between total body water and dialysis related hypertension. PATIENTS AND METHODS: Thirty stable chronic hemodialysis patients were studied. Twenty-four-hour ambulatory blood pressure on the day before dialysis, blood pressure before and after dialysis, weight gain, ultrafiltration and total body water were determined. Total body water was measured by body impedance analysis and expressed as percentage of dry weight (TBW %). Ambulatory blood pressure recordings were defined as hypertensive when the blood pressure load (% of readings above 140/90 mmHg) was more than 40%. RESULTS AND CONCLUSION: Patients, classified as normotensive (n = 11) or hypertensive (n = 19), based on 24-hour blood pressure measurements, had significantly different TBW % (54.7 +/- 5.3 vs. 58.9 +/- 4.6%, p = 0.046). Ambulatory blood pressure and postdialysis blood pressure, but not predialysis blood pressure, were significantly correlated with TBW %. Acute volume changes, as reflected by interdialytic weight gain and ultrafiltration did not correlate with TBW %. These changes correlated weakly with predialysis blood pressure. Multivariate analysis showed that only TBW % and antihypertensive medication had an independent influence on 24-hour blood pressure measurements. We conclude that 24-hour blood pressure and blood pressure after dialysis are better related to total body water than blood pressure before dialysis, which was however weakly related to the acute volume overload, induced by interdialytic weight gain. We hypothesize that this could be the result of a more important chronic volume overload leading to an increase in systemic vascular resistance. On the contrary the acute but less important changes in extracellular volume between dialyses cause no hypertension after dialysis and no sustained hypertension over 24 hours, but only in some cases a temporary increase in the blood pressure just before dialysis. This volume overload can be easily determined by measurement of total body water by bioelectrical impedance analysis.

Aged↗

PubMed1996

Biventricular assist for severe acute rheumatic pancarditis.

Severe heart failure in acute rheumatic myocarditis is rare. It may be rapidly reversible with treatment, so maximal medical treatment and, if necessary, mechanical support should be given before heart transplantation is considered.

Acute Disease↗

PubMed1995

Right-to-left flow through a patent foramen ovale in acute right ventricular infarction. Two case reports and a proposal for management.

Right-to-left shunting through a foramen ovale complicating acute right ventricular infarction and resulting in severe arterial hypoxemia has been described eight times before. Treatment strategies have often aimed at reducing the shunt. Four patients died. Less attention has been paid to attempts at revascularization and, despite a high incidence of atrioventricular conduction disturbances, to temporary dual-chamber pacing. We describe herein two patients with postcardiac surgical right ventricular infarction complicated by severe right-to-left interatrial shunting. Treatment strategy was aimed at improving right ventricular function, and right-to-left shunting ceased. All efforts should be directed at treating right ventricular dysfunction, which is the cause of the clinical picture, and not at reducing the shunt, which is a secondary phenomenon.

Adult↗