Laurence Bontemps

• PhD
• Hospices Civils de Lyon (Centre Hospitalier Universitaire de Lyon)

Background Considering the distinctive characteristics of CZT detectors, automatic quantification of ischemia using normal limits included with software package may deliver suboptimal results for CAD detection. The present study aims to evaluate the benefits of creating normal limits specific to a local population and laboratory protocol. Methods a...

Gated radionuclide ventriculography (RNV) may be used for the evaluation of the right ventricular function. However, the accuracy of the method should be clinically validated in patients suffering from diseases with specific pathology of the right ventricle (RV) and with possible left ventricular (LV) interaction. Three groups of 15 patients each,...

Gated radionuclide ventriculography (RNV), combined with inter- and intraventricular dyssynchrony measurement by phase analysis, is able to evidence right and left ventricular mechanical cardiac disorders and may contribute to the diagnosis of arrhythmogenic right ventricular dysplasia (ARVD). Nevertheless, the patients referred for suspicion of AR...

Phase analysis, developed to assess dyssynchrony from ECG-gated radionuclide ventriculography, has shown promising results. We hypothesized that quantifying the cardiac resynchronization reserve, that is, the extent of response to cardiac resynchronization therapy (CRT), by radionuclide imaging could potentially identify patients who are best suite...

We previously demonstrated that ischemic postconditioning decreases creatine kinase release, a surrogate marker for infarct size, in patients with acute myocardial infarction. Our objective was to determine whether ischemic postconditioning could afford (1) a persistent infarct size limitation and (2) an improved recovery of myocardial contractile...

It is unclear whether the protection observed in human heart following repetition of brief episodes of ischaemia is due to opening of coronary collaterals or to ischaemic preconditioning. We investigated whether the improvement in ST segment change following repeated episodes of brief ischaemia during coronary angioplasty is due to preconditioning...

The functional investigation of cardiac diseases using nuclear techniques involves several variables, such as myocardial perfusion, cellular viability or mechanical contraction. The combined, topographical and quantitative assessment of these variables can characterize the functional state of the heart in terms of normal myocardium, ischemia, hiber...

Despite the rise of myocardial gated SPECT, and, at a lesser extend, of gated blood pool SPECT, planar radionuclide angiography remains the reference technique for left ventricular ejection fraction measurement. In contrast to tomographic methods, which are mostly fully automatic, planar blood pool imaging allows a high degree of interaction with t...

Although well-defined clinically and electrocardiographically, Acquired Long QT Syndrome (LQTS) remains elusive from a pathophysiologic point of view. An increasingly accepted hypothesis is that it represents an attenuated form of Congenital Long QT Syndrome. To test this hypothesis further, we investigated patients with Acquired LQTS, using variou...

This study presents a new tool for the visualization and analysis of three-dimensional (3-D) cardiac single-photon emission computed tomography (SPECT). The first step consisted of computing the 3-D pseudo-skeleton of a binarized myocardium and, using the skeleton points, to design a bullet model (half ellipsoid prolonged by a cylinder). Afterwards...

A peripheral perfusion tracer injection at the time of coronary occlusion during percutaneous transluminal coronary angioplasty (PTCA) may delineate the myocardial 'area at risk' related to a given artery. To evaluate the location, size and severity of the corresponding scintigraphic defects, we conducted a prospective study of 36 patients who rece...

The aim was to investigate in patients receiving doxorubicin whether any alteration in myocardial oxidative metabolism or blood flow as assessed by positron emission tomography (PET) could be observed either after the first dose of the drug, or during its chronic administration. Six female non-heart-failure cancer patients treated with doxorubicin...

This study was designed to prospectively evaluate the effects of radiofrequency ablation in Wolff-Parkinson-White (WPW) syndrome by scintigraphic analysis. The functional changes triggered by radiofrequency current ablation of atrioventricular accessory pathways are not fully known. Forty-four patients with WPW syndrome were consecutively investiga...

To assess the blood flow supply offered to the myocardium by surgical revascularization using bilateral internal mammary (IMAs) and gastroepiploic (GEA) arteries. Two-year assessment by exercise thallium myocardial scintigraphy without medical treatment was performed in 122 patients (mean age 61 +/- 9 years) who underwent coronary artery bypass gra...

Pre-filtering of gated blood pool studies, before fully automatic measurement of left ventricular ejection fraction, should be able to improve the results in terms of success and accuracy, compared to unfiltered series of pictures. We have evaluated 12 filters refering to four different principles (Metz, Wiener, Butterworth and band-pass) and corre...

Previous studies suggested that certain lipid-lowering drugs such as statins suppress ubiquinone, affect mitochondrial function, and may have deleterious effect on skeletal or cardiac muscles with potentially serious clinical consequences, especially in patients with established coronary heart disease and left ventricular dysfunction. In this doubl...

To assess the prognostic factors of myocardial recovery expected after coronary bypass surgery and the impact of surgical technique used, a prospective non-randomized study including a 1-year postoperative evaluation of left ventricular function was performed in patients with left ventricular dysfunction (left ventricular ejection fraction (LVEF) <...

The functional improvements resulting from coronary revascularization (CABG) in patients with depressed ventricular function may be described by the use of a model combining global or local quantification of myocardial perfusion, viability, and contraction. An illustration of this model, with data provided by conventional radionuclide studies as th...

Objective: To assess the prognostic factors of myocardial recovery expected after coronary bypass surgery and the impact of surgical technique used, a prospective non-randomized study including a 1-year postoperative evaluation of left ventricular function was performed in patients with left ventricular dysfunction (left ventricular ejection fracti...

This study was designed in order to evaluate in a more objective manner than visual inspection, the detection of myocardial inferior wall hypofixations in perfusion SPECT. We have studied 90 patients, divided into four groups: GO (7 M, 13 F, 55 ± 21 years) and G1 (9 M, 12 F, 49 ± 26 years) are groups of patients considered as normal; G2 (20 M, 3 F,...

Radiofrequency (RF) ablation of accessory pathways in Wolff-Parkinson- White (WPW) syndrom is supposed to be less aggressive than fulguration while providing excellent results. The aims of our study were therefore the evaluation of the functional results of this therapy in terms of left or right ejection fractions and its effects on the contraction...

In a previous work, we have estimated the left ventricular compliance invasively in animals by using data from both radionuclide ventriculography and intraventricular pressure obtained with a tip micro manometer. In the present study, we are estimating a parameter or index reflecting the cavitary compliance of the left ventricle (ILVC) by using sci...

Invasive and non-invasive methods exist to assess left ventricular compliance (LVC). This work has two parts, one experimental and one clinical. We estimated left chamber stiffness in dogs by using volume data from radionuclide ventriculography (RNV) and left ventricular pressure data, synchronized with a gating system to the intraventricular dp/dt...

Radioisotopic cardiac investigation techniques still have a limited role in intensive care units, mainly due to cumbersome traditional equipment, even if in some cases favourable local circumstances exist, such as the proximity of a nuclear medicine unit or the availability of a mobile gamma camera. Nevertheless, nuclear techniques show a number of...

A series of 30 patients (25 males, 5 females, age=28–73 years) with a clinical indication of thallium-201 stress/4 hours redistribution scintigraphy has been studied using stress/rest (n=7) or rest/stress (n=23) protocols with technetium-99 m teboroxime (CARDIOTEC, Squibb Diagnostics) in order to assess the clinical usefulness of this new molecule...

In order to evaluate the clinical value of a new myocardial perfusion tracer, a series of 30 patients (25 male, 5 female, mean age 56 years) referred for thallium 201 stress/redistribution scintigraphy has been studied using stress/rest (n = 7) or rest/stress (n = 23) protocols with technetium 99m teboroxime (Cardiotec SQUIBB). In all cases coronar...

In order to evaluate the clinical value of a new myocardial perfusion tracer, a series of 30 patients (25 male, 5 female, mean age 56 years) referred for thallium 201 stress/redistribution scintigraphy has been studied using stress/rest (n = 7) or rest/stress (n = 23) protocols with technetium 99m teboroxime (Cardiotec SQUIBB). In all cases coronar...

This article reviews the nuclear cardiology techniques which can be used to assess chest pain. Nuclear techniques can potentially give valuable information on the location and extent of myocardial perfusion abnormalities, the assessment of myocardial viability, and/or presence of myocardial necrosis and the effects, both regional and global, of myo...

In order to study myocardial metabolism by external detection, quantitative information on the metabolism of a gamma-emitting iodinated fatty acid (IHA) was obtained from time-activity curves of radioactivity in different compartments. A 4-compartment mathematical model was then developed; compartments 0, 1, 2, and 3 correspond respectively to vasc...

The aim of the present study was to demonstrate that it is possible to estimate the intracellular metabolism of a fatty acid labelled with iodine using external radioactivity measurements. 123I-16-iodo-9-hexadecenoic acid (IHA) was injected close to the coronary arteries of isolated rat hearts perfused according to the Langendorff technique. The ti...

In order to choose a labelled fatty acid (FA) for the external study of myocardial metabolism, FAs that are different in chain length, saturation, nature and position of the radioactive label, are injected i.v. into mice. Myocardial and blood activities are measured at various times p.i. It appears that hexadecanoic and hexadecenoic acids, iodine l...

External counting, intracellular and subcellular distribution of (16 123I) iodohexadecenoic acid are studied on isolated rat hearts perfused with or without glucose. The presence of an exogenous substrate reduces the fatty acid oxidation and induces an increase of total cardiac and organic fraction activities. In this fraction, activity is very low...

The intracellular and subcellular distribution of 16-(123I)-iodo-9-hexadecenoic acid were studied in isolated rat hearts, perfused with or without glucose. At various time intervals after injection, cardiac lipids were extracted and the activity was determined for all fractions and all lipid classes. The total cardiac activity was maximal within 1...

The methyl-branched fatty acids, if radioiodine labelled in alpha position, are potentially adapted to a selective study of FA myocardial uptake. To determine the position and the number of methyl radicals that are necessary to obtain a maximal uptake and a minimal degradation, we measured time-activity evolution of isolated and perfused rat hearts...