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P Merlet

Publications and source records attributed to P Merlet.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Pre-hospital thrombolysis].

Too few myocardial infarctions are thrombolysed, and the thrombolytic agent is usually administered too late. This situation can conceivably be improved by educating both physicians and patients, by promoting thrombolysis in all hospitals and by performing thrombolysis before admission. We report here our experience of pre-hospital thrombolysis with Eminase in the Val-de-Marne department. This preliminary study is just a small stone added to the big heap of small series of thrombolysis at home published throughout the world. But while the feasibility of pre-admission thrombolysis has been well demonstrated, its effectiveness remains to be accurately determined. Two studies involving large groups of patients are currently in progress: one in Seattle with the left ventricular function as principal criterion of judgment, the other in Europe (The European Myocardial Infarction Project) with mortality as main criterion of judgment. We must wait for the results of these studies to know whether pre-hospital thrombolysis will become the standard treatment of myocardial infarction and if so, to implement the relevant changes required in health structures.

Aged↗
PubMed1990

[Methods for evaluating thrombolytic drugs].

There are two conceptually quite separate objectives to be attained in evaluating a new class of therapeutic agents: the establishment of benefit-risk relationships which allow assessment of their clinical utility; the evaluation of the underlying physiopathological concepts. These two distinct objectives overlap; the criteria of assessment of the benefit-risk studies are based on the physiopathological concepts. Similarly, the relationships observed after analysing the results of the benefit-risk studies increase our understanding of the physiopathology of a disease process. With respect to the use of thrombolytic drugs in the acute phase of myocardial infarction: --the usual criteria of evaluation of the benefits of treatment are coronary artery patency, left ventricular ejection fraction and patient mortality; the severity of blood clotting abnormalities and the frequency of haemorrhage are used to assess the risks; --the physiopathological reasoning behind this choice of criteria of assessment is the direct relationship between coronary artery patency, ejection fraction and mortality. Also, the severity of blood clotting abnormalities seems to be related to the frequency of haemorrhagic complications; We have reviewed these criteria of assessment of the benefit-risk ratio of thrombolysis in the acute stage of myocardial infarction. Our analysis indicates that mortality is the only indiscutable criterion of assessment and that the classical physiopathological concepts are not validated by the results of therapeutic trials.

Clinical Trials as Topic↗
PubMed1990

[Cardiac transplantation. Indications, delays, surveillance].

The number cardiac transplantation has been dramatically increasing for the last year and the results are satisfactory regarding survival or functional capacity. The observed increase of cardiac transplantation may tend to vulgarize it. However, this intervention should be only considered in a selected group of patients who have no other option. Many reports concerned various technical approach for a clearcut determination of high and low risk population of patients with congestive heart failure. But, considering individual patients, the value of each prognostic parameter remains unresolved. Nevertheless the more discriminant parameters for the prognosis assessment are: the left ventricular ejection fraction, the NYHA class, right heart catheterization data, the functional capacity, the cardiothoracic ratio on chest X ray, the ischemic etiology of the disease. The role of neuro-hormonal determinant such as norepinephrine circulating concentration or cardiac uptake on MIBG imaging should be further investigated, especially for patients treated by ACE inhibitors or beta blockers. Contraindications for cardiac transplantation are less restrictive, nowadays. Concerning patients selected, and waiting for heart transplantation or patients non primary selected survival can be improved by adjusting medical therapy on objective efficacy criteria.

Contraindications↗
PubMed1990

[Treatment of chronic left ventricular insufficiency].

Left ventricular failure results from many myocardial diseases: the symptoms of left ventricular failure are the consequence of adaptations which the left ventricle and circulatory system activate to counteract the initial myocardial disease. The aims of treatment of cardiac failure are diverse depending on whether treatment is directed to correct the initial myocardial disease, its myocardial consequences, its circulatory consequences or, more simply, the patient's symptoms. The ideal treatment of cardiac failure would include a drug acting on the cause, a drug restoring left ventricular contraction and relaxation adapted to the conditions of cardiac load, a drug correcting regional blood flow disturbances and a drug relieving symptoms related to salt retention. An ideal drug for chronic left ventricular failure does not exist, and so treatment is a composite effort. Should it be in first intention? This is the current trend.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

[Medical strategy in patients awaiting emergency heart transplantation].

Cardiac transplantation is theoretically the optimal final treatment of terminal cardiac failure but the indications, especially in the emergency situation, should be carefully considered. Sympathomimetic agents are of limited use in patients with severe cardiac failure partly because of the down regulation of the myocardial beta-receptors. The phosphodiesterase inhibitors, represented by enoximone, are valuable because of their action on the cardiac muscle (inotropic and lusitropic) and their direct systemic vasodilator effect. Enoximone can be administered by intravenous bolus resulting in a rapid onset of action (peak at 30 minutes) with a prolonged effect due to its hepatic metabolites. The authors' experience in this indication dates over 5 years and over 50 patients were included. A preliminary study in 34 patients with cardiac failure resistant to betamimetic drugs, referred to the intensive care unit for urgent cardiac transplantation, or, in the absence of a donor, circulatory assistance is reported. A Swan Ganz catheter and radial artery canula were inserted for haemodynamic monitoring and enoximone was administered in an intravenous bolus over 15 minutes every 8 hours in addition to sympathomimetic agents. A haemodynamic improvement was observed after the 30th minute in 30 patients. The cardiac index increased from 1.82 to 2.67 l/mn/m2 and the pulmonary capillary pressures decreased from 30.8 to 18.9 mmHg. Systemic arterial resistances fell from 2,170 to 1,520 dynes.s.cm-5. No haemodynamic improvement was observed in 4 patients who were treated by mechanical ventricular assistance. After investigations to detect contra-indications to cardiac transplantation, 12 of the 30 patients remained candidates for cardiac transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

MIBG scintigraphic assessment of cardiac adrenergic activity in response to altitude hypoxia.

High altitude hypoxia induces a decrease in the cardiac chronotropic function at maximal exercise or in response to isoproterenol infusion, suggesting an alteration in the cardiac sympathetic activation. Iodine-123 metaiodobenzylguanidine [( 123I]MIBG) was used to map scintigraphically the cardiac sympathetic neuronal function in six male subjects (aged 32 +/- 7 yr) after an exposure to high altitude that created hypoxic conditions. Results obtained just after return to sea level (RSL) were compared with the normal values obtained after 2 or 3 mo of normoxia (N). A static image was created as the sum of the 16-EKG gated images recorded for 10 min in the anterior view of the chest at 20, 60, 120, and 240 min after injection. Regions of interest were located over the heart (H), lungs (L), and mediastinum (M) regions. There was a significant decrease in the H/M and the L/M ratios in RSL compared to N condition. Plasma norepinephrine concentration was elevated during the stay at altitude but not significantly different in RSL compared to N. In conclusion, cardiac [123I]MIBG uptake is reduced after an exposure to altitude hypoxia, supporting the hypothesis of an hypoxia-induced reduction of adrenergic neurotransmitter reserve in the myocardium. Furthermore, the observed significant decrease in pulmonary MIBG uptake suggests an alteration of endothelial cell function after exposure to chronic hypoxia.

3-Iodobenzylguanidine↗
PubMed1990

Improved detection of anterior left ventricular aneurysm with multiharmonic fourier analysis.

Single and multiharmonic Fourier analysis of LAO 30-45 degrees gated blood-pool studies were performed in a selected group of 30 patients with a left ventricular anterior aneurysm proven by contrast angiography. The sensitivity of the first harmonic phase image for the diagnosis of ventricular aneurysm was 80%. The clear phase shift (greater than 110 degrees) between the normal and the aneurysmal areas was missing in six patients. Peak acceleration images (negative maximum of the second derivative of the Fourier series) were calculated for each pixel with the analytical Fourier formula using two or three harmonics. A clear phase shift (greater than 126 degrees) than appeared in all the patients. This improvement was related to the increased weight of the second and third harmonics in the aneurysmal area when compared to control patients or to patients with dilative cardiomyopathy. Multiharmonic Fourier analysis clearly improved the sensitivity of the diagnosis of anterior left ventricular aneurysm on LAO 30 degrees-45 degrees gated blood-pool images.

Cardiomyopathy, Dilated↗
PubMed1989

Reversal of hypoxia-induced decrease in human cardiac response to isoproterenol infusion.

A decrease in heart rate response to isoproterenol (IP) infusion has been previously described in humans exposed to acute (2-3 days) or chronic (21 days) exposure to altitude hypoxia (J. Appl. Physiol. 65: 1957-1961, 1988). To evaluate this cardiac response in subacute (8 days) hypoxia and to explore its reversal with restoration of normoxia, six subjects received an IP infusion under normoxia (condition N), after 8 days in altitude (4,350 m, condition H8), on the same day in altitude after inhalation of O2 restoring normoxic arterial O2 saturation (SaO2, condition HO), and 6-11 h (condition RN) and 4-5 mo (condition ND) after the return to sea level. Cardiac chronotropic response to IP, evaluated by the mean increase in heart rate from base value (delta HR, min-1), was lower in condition H8 [mean 30 +/- 13 (SD)] than in condition N (50 +/- 14, P less than 0.03); it was slightly higher in condition HO (38 +/- 14) or condition RN (42 +/- 15) than condition H8 but still significantly different from condition N (P less than 0.03), despite normal values of SaO2. delta HR in condition ND (55 +/- 10) returned to base N value. These findings confirm the hypothesis of a hypoxia-induced decrease in cardiac chronotropic function. Two possible mechanisms are suggested: an O2-dependent one, rapidly reversible with recent restoration of normoxia, and a more slowly reversible mechanism, probably a downregulation of the cardiac beta-receptors.

Adult↗
PubMed1989

[Physiopathologic basis of the use of thrombolytic agents during the acute phase of myocardial infarction].

Experimental animal studies have shown that coronary occlusion is followed by myocardial infarction and that coronary reperfusion can limit infarction size. Myocardial necrosis and the recovery of function are progressive phenomena in these animal models. Similarly, human myocardial infarction is caused by coronary occlusion and the size and severity of the infarct can be reduced by spontaneous or therapeutic coronary reperfusion. However, there are important differences between the animal models and clinical myocardial infarction. The results of randomised therapeutic trials of thrombolytic drugs show that the theoretical equation between reperfusion, myocardial protection and reduction of mortality has not yet been fully validated. This may be explained either by the fact that the intermediary criteria of assessment (patency at 90 minutes and ejection fraction at the 3rd week) have been badly chosen or by the fact that some of the therapeutic benefit of thrombolytics on mortality is not due to reperfusion or myocardial protection. The physiopathological rationale behind the use of thrombolytics in the acute phase of myocardial infarction is coronary reperfusion, but is reperfusion beneficial in all myocardial infarcts? What is or are the intermediary factors between reperfusion and the decrease in mortality? Is reperfusion the only benefit of thrombolysis? Clear answers to these questions are not yet available.

Animals↗
PubMed1988

Automatic drawing of the left epicardial region of interest on thallium 201 scintigraphic images.

An algorithm has been written which automatically selects a left epicardial region of interest on 201Tl myocardial images. It accomplishes a radial search from the geometric center of the myocardium. On each of the 30 profiles, the local maximum of the 1st derivative is selected as the epicardial edge. The algorithm has been tested in 40 patients at stress and redistribution. In ten patients, conventional planar images were obtained in three views. In 30 patients conventional short axis tomographic images were obtained after reconstruction of 32 projections acquired over 180 degrees. The rate of success is 97% for both imaging modalities. This procedure is another step towards fully automated assessment of myocardial defects and redistribution.

Algorithms↗
PubMed1988

ECG gated thallium 201 myocardial images: value in detecting multivessel disease in patients on anti anginal therapy 1-3 months after myocardial infarction.

ECG gated 201Tl scintigraphy was compared to non gated images for detecting 2-3 vessel disease 1-3 months after a first uncomplicated myocardial infarction. In all, 111 patients on anti anginal treatment underwent coronary arteriography and stress thallium imaging; 39 showed single vessel disease (SVD), and 72 multivessel disease (MVD). Sensitivity of black and white analog images was 82% for SVD and 8% for MVD. Sensitivity of computerized colored static images was 87% for SVD and 33% for MVD. For gated images, sensitivity was 100% and 92% in patients with SVD and MVD respectively. Specificity for detecting MVD was 95% for black and white images, 77% for computerized colored static images, and 69% for ECG gated images. Thus, ECG gated exercise 201TL scintigraphy is useful for predicting the extent of coronary artery disease 1-3 months after myocardial infarction in patients on anti anginal therapy.

Angina Pectoris↗
PubMed1988

Non-invasive measurement of pulmonary arterial pressure: I. A haemodynamic modelling approach.

In order to monitor pulmonary arterial pressure (P) by any non-invasive imaging technique, a haemodynamic model of blood flow kinetics and wall mechanics has been developed. It is a one-dimensional model of pulsatile flow in an elastic pulmonary arterial trunk, assuming that blood is an incompressible fluid and viscous effects are negligible. The equations are P(t)-Pd = rho c2lnS(t)/Sd-1/2pw-2(t) Pd = (Sd/Ss)1/2Pp where, at any time of the ejection phase of systole, P(t), S(t) and w(t) are the pulmonary arterial pressure, cross-sectional area of the pulmonary artery and blood velocity averaged on the cross section S, respectively, PP is the pulse pressure, the difference between the peak systolic pressure and the diastolic pressure Pd; rho is blood density, c pulse wave velocity, and Ss and Sd are maximum (systolic) and minimum (diastolic) values of the cross-sectional area S. Using these equations, P(t) can be calculated if the three parameters, i.e. c, S(t) and w(t) are measured. So far, it has been impossible to measure the pulse wave velocity c non-invasively. We have investigated the calculation of c from S(t) and w(t) using the equation of continuity in the absence and presence of reflected pressure waves. The hypotheses of the haemodynamic model are discussed.

Blood Flow Velocity↗
PubMed1988

[Dose-response relation of intravenous enoximone in congestive cardiac insufficiency].

Enoximone (MDL 17043) is a new generation inotropic drug which acts by inhibiting phosphodiesterase and is endowed with both inotropic and vasodilator properties. The purpose of this study, which involved 23 patients aged from 18 to 75 years in NYHA class III or IV and with evidence of severe haemodynamic disturbances (cardiac index below 2.5 1/mn/m2, pulmonary wedge pressure above 15 mmHg), was to evaluate the acute haemodynamic responses to doses of enoximone that ranged from 0.25 to 2.50 mg/kg administered by bolus intravenous injection. Heart failure was either of ischaemic origin (6 cases) or idiopathic (10 cases) or due to various causes (7 cases). Group A patients (n = 11) received the drug in low doses (less than or equal to 1 mg/kg) as opposed to group B patients (n = 12) who were given high doses (greater than 1 mg/kg). Results were evaluated from the amplitude and duration of the haemodynamic response at maximum effect time (30 min). The following parameters were measured: cardiac index, pulmonary wedge pressure, systemic vascular resistance, mean arterial pressure and heart rate. Cardiac index and pulmonary wedge pressure were significantly improved in both groups (P less than 0.005): cardiac index +39 p. 100 in group A, +55 p. 100 in group B; pulmonary wedge pressure -36 p. 100 in group A, -48 p. 100 in group B; systemic vascular resistance -46 p. 100 in group B. Heart rate and arterial pressure were not significantly altered. The duration of response was 1 to 3 hours in group A patients and 4 to 8 hours in group B patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Evaluation of 3 dimensional space and time filtering on ECG gated 201Tl myocardial images.

Stress 201Tl myocardial images were obtained using a standard ECG gated acquisition protocol for 10 min per view. These images were filtered using a three dimensional space and time filter. The effects of filtering were evaluated by sectorial analysis. Comparing raw and filtered dynamic images, quantification demonstrated that filtering did not produce artefacts. A conventional static image was also obtained as the sum of the series of unfiltered dynamic images. Comparison of raw static and filtered diastolic images indicated that the latter demonstrated myocardial abnormalities more clearly (P less than 0.01) in 33 patients. Improvement in the signal to noise ratio produced by filtering made cinematic display and visual analysis possible which was not feasible with raw gated images. Clinical evaluation is in progress.

Diastole↗
PubMed1984

[Primary pulmonary lymphoma].

The authors report 2 cases of primary pulmonary lymphoma. The first case was a 65 year old woman with a diagnosis of lymphocytic lymphoma confirmed by surgical biopsy, after being suspected on the basis of bronchoscopic biopsies and bronchiolo-alveolar aspiration. Twenty one months after the beginning of treatment with chemotherapy and six months after this treatment was completed, the patient was in complete remission. The second patient was a 52 year old man who underwent left inferior lobectomy for a lympho-plasmacytic lymphoma, which was only diagnosed definitively on the operative specimen. The authors discuss the clinical and radiological features and the histological and immunological criteria of primary pulmonary lymphomas (PPL). There are a number of related diseases with varying degrees of malignancy: interstitial lymphocytic pneumonitis (ILP), pseudo-lymphoma, which corresponds to a localised form of ILP, lymphomatoid granulomatosis (LYG) and pulmonary lymphoma, which usually has a lymphocytic or lympho-plasmocytic cell type.

Aged↗