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Biomedical subjects

P Decoodt

Publications and source records attributed to P Decoodt.

At least 19 recordsLinked to original sources

European certification of clinical competence in adult echocardiography issued in Belgium. The Steering Committee of the Belgian Working Group on Echocardiography and Cardiac Doppler.

In accordance with the European proposals, adapted guidelines are proposed for a certification of clinical competence in adult echocardiography, with transoesophageal echocardiography as a special option. The conditions required to be candidate to the certification, the exemptions of practical training for long-term echocardiographers and the organisation of the training itself are successively considered. Standards for training, site accreditation, official logbook characteristics, minimal numbers of examinations and minimal stage duration are defined. Content of theoretical training, as well as organisation of formal and informal education and of final examination, are described.

Adult

Biplane transesophageal echocardiographic diagnosis of cor triatriatum.

A transthoracic echocardiogram disclosed a linear structure in the left atrium of an adult presenting with atypical chest pain. Biplane transesophageal echocardiography revealed a cor triatriatum. The longitudinal plane was most useful for the assessment of the membrane orifice and the Doppler flow pattern.

Cor Triatriatum

Membranous subvalvular pulmonary stenosis in complete transposition of the great arteries: usefulness of serial exercise testing.

A 22-year-old male who had Mustard repair for complete transposition presented with progressive exercise intolerance, documented by a gradual decrease in exercise capacity on cycle ergometer. Cardiac catheterization and angiography demonstrated subvalvular pulmonary stenosis. After surgical relief of the obstruction, exercise capacity returned to previous level.

Adult

[Vasovagal syncope: the value of tilt-table testing in the evaluation of loss of consciousness].

Syncope, an eminently frequent syndrome, has multiple and varied causes. Its diagnosis is important in view of the poor prognosis of cardiac syncopes and also of the morbidity and discomfort associated with the other etiologies. Unfortunately, the cause eludes us in half the patients so that a clear prognosis and effective therapy can be given to only a few patients. Tilt-table testing, alone or with isoproterenol, is now considered as a noninvasive, sensitive and specific method for identifying patients predisposed to vaso-vagal syncope, a major cause of syncope of unknown origin. Tilt-table testing also helps in tracking many pathologies contributing to syncopes. In the absence of a universal treatment of vasovagal syncope, tilt-table testing has revealed itself as a contributory guide to the best possible treatment.

Adult

Membranous subvalvar pulmonary stenosis in complete transposition; advantage of biplane transoesophageal echocardiography for the diagnosis in a young adult.

A young adult who had previously undergone a Mustard repair for complete transposition developed symptomatic left ventricular outflow tract obstruction. Biplane transoesophageal echocardiography allowed an optimal preoperative assessment. In the longitudinal plane, a discrete calcified membrane was imaged. Consequently, a pulmonary arteriotomy was chosen for the relief of the malformation.

Adult

[Localization of the accessory pathway and surgical treatment in Wolf-Parkinson White syndrome].

The accessory bypass tracts are responsible for many episodes of supraventricular arrhythmias in man. The Wolff-Parkinson-White syndrome is the best example. These arrhythmias can be refractory to the medical treatment and are sometimes lethal. Different techniques can be used to destroy these pathways. The surgical dissection is the most widely accepted technique. The accessory pathways are made of working muscle and are neither visible, nor palpable by the surgeon. The electrical properties of these pathways are used to localize them. These techniques are either non-invasive or invasive. The non-invasive techniques consist of the careful analysis of the surface electrocardiogram in sinus rhythm and during tachycardia. The invasive techniques consist of a pre-operative electrophysiological study and intra-operative mapping. The electrophysiological study consists of the introduction of multiples catheters inside the heart through peripheral veins. The intra-operative mapping consists of measurements done on the surface or inside the heart after the chest has been open. After precise localization of the areas of insertion of these abnormal tracts the surgeon proceeds with the dissection, starting either on the epicardial or on the endocardial side of the heart. The surgical results are excellent and there are only few complications. These techniques were used to operate six patients presenting with the Wolff-Parkinson-White syndrome.

Adolescent

Left atrial myxoma associated with systemic AA amyloidosis.

A 76-year-old woman presenting with generalized amyloidosis of the AA-type protein was found to have a left atrial myxoma. Retrospective estimation of the concentration of SAA protein, a serum precursor of AA amyloid, before and after surgical removal of the myxoma, showed that the SAA protein had disappeared after the operation. A common manifestation of myxoma is the development of a severe inflammatory syndrome that sometimes simulates rheumatic fever or bacterial endocarditis. However, to our knowledge, it has never been described in association with amyloidosis. We suggest that atrial myxoma should be added the list of neoplastic and inflammatory diseases predisposing to AA amyloidosis.

Aged

Predictors of the variation of the ejection fraction during exercise in patients with and without coronary heart disease.

The aim of this study was to determine the factors influencing the different response of the ejection fraction (EF) of the left ventricle at exercise observed in patients with and without significant coronary heart disease. We have studied 98 patients referred for coronary angiography (82 men, 16 women), of whom 49 patients had a previous myocardial infarction and 71 patients had significant coronary heart disease. Exercise testing was performed and combined with a cardiac blood pool imaging at equilibrium. The variation of the EF between rest and peak exercise (delta EF) was measured. Twelve clinical, exercise-related, isotopic, and coronary arteriographic variables were examined in a linear univariate and statistical analysis. In the univariate regression, seven variables were significant regressors on the delta EF. In the multivariate regression, only four variables were significant regressors on the delta EF. Three independent predictors were found: the rate-pressure product, the ST depression, and the occurrence of a previous myocardial infarction. These three independent predictors reflect the myocardial functional reserve.

Coronary Disease

Relationships between plasma epinephrine, norepinephrine, dopamine and angiotensin II concentrations, renin activity, hemodynamic state and prognosis in acute heart failure.

The relationships between hemodynamic state and plasma components of the renin-angiotensin and adrenergic nervous systems were studied in 42 patients admitted to an intensive care unit with acute heart failure. Patients were allocated to four subsets according to cardiac output and pulmonary wedge pressure. Plasma renin activity and angiotensin II were abnormally high in most patients with cardiac output less than or equal to 3.81 X min-1 and pulmonary wedge pressure greater than or equal to 18 mm Hg in contrast with values of patients of the 3 other subsets, which overlapped the normal range. On the other hand, plasma catecholamines were abnormally high in most patients. Angiotensin II was positively correlated with pulmonary wedge pressure, urea and catecholamines and negatively correlated with cardiac output and natremia. Norepinephrine was uncorrelated with hemodynamic parameters but epinephrine was negatively correlated with cardiac output. A discriminant linear function was calculated for prognosis of survival: cardiac output was the most important factor. The rise of angiotensin II and epinephrine were not unfavorable factors if their correlations with other factors (e.g. cardiac output and urea) were taken into account.

Acute Disease

Cardiac tamponade as first manifestation of colonic cancer.

Metastatic cardiac tamponade was the presenting manifestation of a colonic carcinoma. The patient's condition improved after surgical treatment and shows no sign of recurrence of pericardial effusion after more than eight months of systemic chemotherapy. Metastatic pericardial effusions and their treatment are discussed.

Adenocarcinoma

Assessment of left ventricular filling by echocardiography in normal subjects and in subjects with coronary artery disease and with asymmetric septal hypertrophy.

To examine the time course of left ventricular filling, a computerized analysis of echocardiograms was performed in 16 normal subjects, 10 patients with coronary artery disease (CAD) but no cardiac enlargement and 7 patients with asymmetric septal hypertrophy (ASH). After hand-controlled digitization of the echocardiogram, a plot of the left ventricular diameter time-curve demonstrated separate phases of rapid filling, slow filling and atrial contribution. The left ventricular diameter at end-systole and at the end of the three diastolic phases was determined by pattern analysis of the diameter-time curve. On analysis of successive beats in the normals, the coefficient of variation for each of these four values of the left ventricular diameter was less than +/- 5%. Between CAD, ASH and normals there was no significant difference in left ventricular end-diastolic diameter, nor in the extent and percentage of diameter shortening during systole. In contrast, abnormalities of the filling pattern were found in CAD and ASH. The maximal rate of diameter lengthening was not different in CAD (13.0 vs 13.7 cm/sec in normals, N.S.) but decreased in ASH (9.3 cm/sec, p less than .01). The percentage of diameter lengthening occurring in the rapid filling phase was decreased in both patient groups (55% in CAD and ASH vs 73% in normals, p less than .001). The slow filling phase did not contribute to more diameter lengthening (13% in CAD and 17% in ASH vs 12% in normals, N.S.). In CAD and ASH, the atrial contribution was markedly increased (33% in CAD and 28% in ASH, vs 15% in normals, p less than .001), and there was a higher rate of diameter lengthening during the atrial contraction (7.6 cm/sec in CAD, p less than .001 and 5.7 cm/sec in ASH, p less than .01, vs 3.1 cm/sec in normals). In conclusion, after computer processing, noninvasive measurements of the left ventricular diameter allows to identify a typical filling pattern in patients with CAD and ASH, consistent with an abnormal compliance of the left ventricle and a compensatory increased atrial contribution.

Adult

Determination of glomerular intracapillary and transcapillary pressure gradients from sieving data. II. A physiological study in the normal dog.

The two theoretical models proposed previously to calculate the intracapillary and transcapillary glomerular pressure gradients from the sieving of macromolecules such as PVP have been used to analyse in 22 normotensive dogs the sieving curve relating the sieving coefficients, phi, to molecular size (phi: glomerular clearance of PVP fractions/GFR). Neither the "local c2" model-filtrate unmixed at the outer face of the capillaries walls--nor the constant c2 model-filtrate well mixed--allowed to obtain realistic values for the hemodynamical parameters. Indeed with the local c2 model, the best fit between calculated and experimental sieving curves could be obtained only by reversing the intracapillary pressure gradient; conversely the constant c2 model obliged to decrease the intracapillary pressure so abruptly along the capillaries, that retrofiltration took place in the distal parts of the vessels. This difficulty has been overcome by combining the two models; the so-called "hybrid model" considers that the filtrate is well mixed in the vicinity of the urinary pole only. The following results were obtained: 1. PGCa and PGCe (intracapillary pressures at the afferent and efferent extremities of the capillaries) equal to 49.7 +/- 1.03 and 41.8 +/- 1.00 mm Hg respectively. 2. Pressure equilibrium is generally reached at the efferent extremity of the vessels. 3. The slope of PGC (see article) varies inversely to FF. (filtration fraction). 4. The model, however, does not allow to rule out the possibility of retrofiltration.

Animals

Determination of glomerular intracapillary and transcapillary pressure gradients from sieving data. I. A mathematical model.

Determination of glomerular intracapillary and transcapillary pressure gradients from sieving data. A biomathematical model is described to calculate the intracapillary and transcapillary glomerular pressure gradients from the sieving coefficients (phi: fractional clearances/GFR) of macromolecules such as polyvinylpyrrolidone (PVP). Two differential equations have been developed. The first one calculates local values for GFR in terms of local values for PGC (intracapillary hydrostatic pressure) and pi (oncotic pressure). The second equation calculates the clearance of PVP equimolecular fractions, the sieving equations previously described (24) being used to derive the concentrations of PVP in the filtrate (c2). Two variants of the second equation have been considered, assuming the filtrate in contact with the membrane either "well stirred" or "unstirred" (constant c2 and local c2 gradient models respectively). Computer simulations have been used to illustrate how the sieving curve is modified when the five parameters on which depends the shape of the curve are changed one by one. The sieving curve relates phi to a(s) (hydrodynamically equivalent molecular radius). The determining parameters are: GFP, the mean effective glomerular filtration pressure, epsilon, the slope of the intracapillary pressure, FF, the filtration fraction, Cp0, the protein concentration in arterial plasma and r, the pore radius which is the only structural parameter involved when one assumes the glomerular membrane crossed by cylindrical pores of uniform size and length. The shape of the sieving curve is modified significantly enough by changing GFP, FF and r within reasonable limits, to make it possible to derive GFP and r from experimental sieving data for macromolecules such as PVP or dextrans.

Capillaries