Publications by authors named "Jacques A Melin"
Objectives: The purposes of this study were to test whether quantitative real-time myocardial contrast echocardiography (RT-MCE) can detect coronary disease during pharmacologic stress and to compare this approach with single-photon emission computed tomography (SPECT).
Background: Assessing myocardial perfusion during stress is important for the diagnosis and risk stratification of patients with coronary disease.
Method: Thirty-five patients referred for coronary angiography underwent RT-MCE and technetium-99m methoxyisobutylisonitrile (MIBI) SPECT at baseline and after 0.
Background: The purpose of this study was to examine the ability of real-time myocardial contrast echocardiography (MCE) with power modulation to quantitate myocardial blood flow (MBF) and to assess its transmural distribution in open-chest dogs undergoing partial or total coronary stenoses.
Methods And Results: MBF was measured in 12 dogs instrumented with a cuff occluder around the left anterior descending coronary artery at rest, during partial coronary stenosis (during infusion of adenosine), and during coronary occlusion. The MCE-derived rate of microbubble velocity, beta, and myocardial blood volume, A, were obtained by curve fitting of videointensity versus time plots, after the transient destruction of microbubbles by high-energy ultrasound.
Intermittent harmonic imaging with contrast is increasingly used to detect perfusion defects in patients with coronary disease. To achieve this, image homogeneity and the ability to visualize segments on the lateral and distal portions of the imaging field are important. The objective of this study was to evaluate whether the use of specific postprocessing algorithms, such as background subtraction with color coding and parametric display, allows for improved image homogeneity compared with conventional intermittent second harmonic imaging.
View Article and Find Full Text PDFBackground: Functional mitral regurgitation (MR) is common in patients with heart failure and left ventricular (LV) dysfunction, and its severity may vary over time, depending primarily on the loading conditions. Because dynamic changes in the severity of functional MR may affect forward stroke volume, we hypothesized that exercise-induced changes in MR severity influence the stroke volume response of patients with LV dysfunction to exercise, and hence their exercise capacity.
Methods And Results: Heart failure patients (n=25; mean age 53+/-12 years) with LV dysfunction underwent dynamic bicycle exercise at steady-state levels of 30%, 60%, and 90% of predetermined peak VO2.
Unlabelled: This study analyzed the incidence and clinical significance of reverse redistribution (RR) on stress-redistribution (201)Tl SPECT studies in patients with poor left ventricular function and tested the hypothesis that the RR phenomenon could be caused by artifacts.
Methods: Seventy-three consecutive patients with chronic coronary artery disease and left ventricular dysfunction (ejection fraction, 36% +/- 12%) who underwent exercise-redistribution-reinjection (201)Tl SPECT before myocardial revascularization were included. Recovery of left ventricular systolic function was assessed with 2-dimensional echocardiography performed before and 5.
Unlabelled: There is intense controversy as to the mechanisms underlying chronic but reversible left ventricular (LV) ischemic dysfunction. The aim of this study was to investigate the physiology underlying this condition in a canine model of noninfarcted collateral-dependent myocardium.
Methods: Six mongrel dogs were instrumented with ameroid constrictors on the left circumflex and right coronary arteries and a partial occluder on the left anterior descending coronary artery.