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Results 201 - 250 of 1600
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Maurer Mathew S - - 2005
BACKGROUND: Although heart failure with a normal ejection fraction (HFNEF) is a clinically heterogeneous syndrome, a single pathophysiologic mechanism, diastolic dysfunction, is often ascribed to explain this condition. In view of the clinical heterogeneity of these patients, we hypothesized that subgroups of HFNEF patients may have different underlying pathophysiologic mechanisms. ...
Hofer C K - - 2005
BACKGROUND: End-diastolic volume indices determined by transpulmonary thermodilution and pulmonary artery thermodilution may give a better estimate of left ventricular preload than pulmonary capillary wedge pressure monitoring. The aim of this study was to compare volume preload monitoring using the two different thermodilution techniques with left ventricular preload assessment by ...
How Ole-Jakob - - 2005
In the present study, we tested the reliability of measurements of pressure-volume area (PVA) and oxygen consumption (MVo(2)) in ex vivo mouse hearts, combining the use of a miniaturized conductance catheter and a fiber-optic oxygen sensor. Second, we tested whether we could reproduce the influence of increased myocardial fatty acid ...
Ferrari Markus - - 2005
In 2 patients with the Jarvik 2000 left ventricular assist device (LVAD), we assessed left ventricular systolic function through pressure-volume loops and E(max) at the beginning and end of the support period to potentially predict the possibility of pump removal without transplantation. Immediately before LVAD implantation and explantation, pressure and ...
Ripoli Andrea - - 2005
OBJECTIVES: We sought to assess the effects of subclinical hypothyroidism (SHT) on the cardiac volumes and function. BACKGROUND: The cardiovascular system is one of the principal targets of thyroid hormones. Subclinical hypothyroidism is a common disorder that may represent "early" thyroid failure. METHODS: Thyroid profile was evaluated in 30 females ...
Nishimura Yoshiharu - - 2005
It has been reported that in the excised cross-circulated dog heart model, cardiac cooling increases Emax (contractility index) and the external work (EW) of the left ventricle without affecting the systolic pressure volume area (PVA)-independent myocardial oxygen consumption (VO2). However, it remains unclear whether this cooling inotropism and oxygen-saving effect ...
Hudsmith Lucy E - - 2005
PURPOSE: The aim of this project was to establish a database of left and right ventricular and left atrial dimensions in healthy volunteers using steady-state free precession cardiac magnetic resonance imaging, the clinical technique of choice, across a wide age range. METHODS: 108 healthy volunteers (63 male, 45 female) underwent ...
Smart Neil - - 2005
BACKGROUND: Previous work suggesting a better correlation of diastolic than systolic function with exercise capacity in heart failure may reflect the relative insensitivity and load-dependence of ejection fraction (EF). We sought the correlation of new and more sensitive methods of quantifying systolic and diastolic function and filling pressure with functional ...
Langer S F J - - 2005
The left ventricular isovolumic pressure decay, obtained by cardiac catheterization, is widely characterized by the time constant tau of the exponential regression p(t)=Pomega+(P0-Pomega)exp(-t/tau). However, several authors prefer to prefix Pomega=0 instead of coestimating the pressure asymptote empirically; others present tau values estimated by both methods that often lead to discordant ...
Wang Jia-Jung - - 2005
We propose new contractility indexes, in the work, which are equivalent to the conventional contractility (Ees) determined with the slope of left ventricular (LV) end-systolic pressure-volume relation. Nineteen patients with acute myocardial infarction (AMI) were recruited in the study. They received thrombolytic therapy within 24 hours after the AMI event, ...
Schreuder Jan J - - 2005
OBJECTIVE: Surgical left ventricular restoration by means of endoventricular patch aneurysmectomy in patients with postinfarction aneurysm should result in acute improved left ventricular performance by decreasing mechanical dyssynchrony and increasing energy efficiency. METHODS: Nine patients with left ventricular postinfarction aneurysm were studied intraoperatively before and after ventricular restoration with a ...
Wang Jia-Jung - - 2005
The purpose of the study is to investigate the effect of thrombolysis on the relationship between the left ventricular (LV) maximum elastance (Emax) and effective arterial elastance (Eart) in 20 patients with acute myocardial infarction (AMI). LV pressures and volumes of the patients were measured with Millar and multi-electrode volume ...
Hahn Jin-Oh - - 2005
An adaptive approach is proposed for the problem of left ventricular ejection time (LVET) estimation using peripheral pressure waveform signals. The proposed algorithm, which makes use of 2 peripheral pressure measurements, makes it possible to adaptively estimate the LVET in response to different cardiovascular physiologic states. The algorithm builds on ...
Bombardini Tonino - - 2005
In the standard accepted concept, contractility is the intrinsic ability of heart muscle to generate force and to shorten, independently of changes in the preload or afterload with fixed heart rates. At molecular level the crux of the contractile process lies in the changing concentrations of Ca2+ ions in the ...
Uemura Kazunori - - 2004
Using Bluetooth wireless technology, we developed an implantable telemetry system for measurement of the left ventricular pressure-volume relation in conscious, freely moving rats. The telemetry system consisted of a pressure-conductance catheter (1.8-Fr) connected to a small (14-g) fully implantable signal transmitter. To make the system fully telemetric, calibrations such as ...
Schaefer Wolfgang M - - 2004
Gated myocardial perfusion SPECT allows assessment of left ventricular end-diastolic volume (EDV), left ventricular end-systolic volume (ESV), left ventricular stroke volume (SV), and left ventricular ejection fraction (LVEF). Acquiring images with the patient both prone and supine is an approved method of identifying and reducing artifacts. Yet prone positioning alters ...
Cheung Michael M H - - 2004
AIM: The myocardial performance index (MPI), or Tei index, has been shown to be useful in the assessment of global myocardial performance. There are few invasive data however, which examine its load dependence or sensitivity to acute changes in contractile function. The purpose of this study was therefore to study ...
Mehra M R - - 2004
BACKGROUND: Allograft adaptation to a foreign circulation is imperfect as noted from persistent limitations to stress. Effective arterial elastance (Ea), a measure of afterload, provides an estimate of aortic impedance. End systolic elastance (Ees) is a load-independent measure of ventricular performance as well as its interaction in the periphery. The ...
Stekelenburg-de Vos Sandra - - 2005
Cardiac pressure-volume relations enable quantification of intrinsic ventricular diastolic and systolic properties independent of loading conditions. The use of pressure-volume loop analysis in early stages of development could contribute to a better understanding of the relationship between hemodynamics and cardiac morphogenesis. The venous clip model is an intervention model for ...
Hay Ilan - - 2005
Although present in many patients with heart failure and a normal ejection fraction, the role of isolated impairments in active myocardial relaxation in the genesis of elevated filling pressures is not well characterized. Because of difficulties in determining the effect of prolonged myocardial relaxation in vivo, we used a cardiovascular ...
Waters Emily A - - 2005
During one cardiac cycle, the volume encompassed by the pericardial sack in healthy subjects remains nearly constant, with a transient +/-5% decrease in volume at end systole. This "constant-volume" attribute defines a constraint that the longitudinal versus radial pericardial contour dimension relationship must obey. Using cardiac MRI, we determined the ...
Alvarez Jorge A - - 2004
It is unclear whether the increase in availability of substrates for energy production in diabetes can lead to enhanced systolic function early in the disease, before the onset of structural changes to the myocardium. To examine this issue, BKS.Cg-m +/+ Lepr db (db/db) mice with type 2 diabetes and wild ...
DiDonato M - - 2004
Cardiac failure is frequently complicated by intra and or interventricular conduction delay that results in dyssynchronized cardiac contraction and relaxation. In contrast to an electrical intervention by biventricular pacing, this study tests the capacity of geometric rebuilding by surgical ventricular restoration (SVR) to restore a more synchronous contractile pattern through ...
Aessopos Athanasios - - 2004
OBJECTIVE: To study the effects of chronic severe anemia on the aging heart. METHODS: We studied 41 elderly patients (mean age 69.8 yr, standard deviation [SD] 3.9 yr) suffering from chronic severe anemia (mean hemoglobin 6.3, SD 0.5 g/dL) with no history of cardiac disease, along with 63 healthy age- ...
Lytrivi Irene D - - 2004
The right ventricle of subjects after infundibulotomy (n = 20) and of subjects free of right ventricular disease (n = 19) was partitioned into the infundibular and sinus segments to examine the relative size and function of each. Excellent agreement was found between observers for measuring regional volume and ejection ...
Vanhove Christian - - 2005
PURPOSE: The aim of this study was to investigate the intra-individual reproducibility of left ventricular volume and ejection fraction measurements in living rat using pinhole gated single-photon emission computed tomography (SPECT). METHODS: Eight normal male Wistar rats underwent four pinhole gated SPECT acquisitions over a 1-month period. Two pinhole gated ...
Popovic Zoran B - - 2005
In the recently published clinical study [Use of Nitroprusside in Left Ventricular Dysfunction and Obstructive Aortic Valve Disease (UNLOAD)], sodium nitroprusside (SNP) improved cardiac function in patients with severe aortic stenosis (AS) and left ventricular (LV) systolic dysfunction. We explored the possible mechanisms of these findings using a series of ...
Kumar Anand - - 2004
OBJECTIVE: To evaluate the efficacy of a novel lipopolysaccharide (LPS) antagonist, E5531, in blocking LPS-induced cardiac responses including myocardial depression (as assessed by relatively load-independent echocardiographic indices of contractility) in a human model of experimental endotoxemia. DESIGN: Randomized, prospective, placebo-controlled, double-blind trial. SETTING: ICU procedure room. PARTICIPANTS: Thirty-two healthy, male ...
Higuchi Takahiro - - 2004
The objective of the present investigation was to determine the feasibility of assessing left ventricular systolic ejection and diastolic filling via the automatic edge detection method employing ECG-gated blood pool single-photon emission tomography (SPET GBP) data. METHODS: Thirty-five patients, who had undergone both SPET GBP and ECG-gated equilibrium blood pool ...
Villars Penelope S - - 2004
Left ventricular diastolic function plays an important role in cardiac physiology. Lusitropy, the ability of the cardiac myocytes to relax, is affected by both biochemical events within the myocyte and biomechanical events in the left ventricle. Beta-adrenergic stimulation alters diastole by enhancing the phosphorylation of phospholamban, a substrate within the ...
Ewert Dan - - 2004
Experiments were performed to test the hypothesis that viscoelastic properties of the swine myocardium are independent of heart rate (HR), preload (PL), and afterload (AL). Left ventricular pressure and aortic flow (AoF) waveforms were recorded in 13 swine. At different paced heart rates, an inferior vena caval occlusion (IVC) was ...
Robotham James L - - 2004
In a clinical investigation, Kumar and coworkers reported the hemodynamic events that accompany plasma volume expansion over 3 hours in healthy adult volunteers, and found that increases in stroke volume (SV) may be related to increases in left ventricular (LV)/right ventricular (RV) end-diastolic volume, as they expected, but also to ...
Langer Stefan F J - - 2004
The decelerative part of the left ventricular isovolumic pressure decay is an important phase to make the heart ready for diastolic refill (lusitropy). Its widely used characterization by an exponential regression with zero pressure asymptote or coestimated asymptote provides empirically biased time constant estimates because of significant deviations of the ...
Razzolini Renato - - 2004
Ventriculo-arterial coupling, defined as the ratio of the effective afterload (Ea) to contractility (Ees), reflects the mechano-energetic performance of the heart and is increased in chronic heart failure (CHF); the aim of treatment is to reduce its value. We studied the effect of carvedilol on the Ea/Ees ratio in patients ...
Sonntag Steffen - - 2004
OBJECTIVES: We assessed the effects of levosimendan on left ventricular (LV) function in patients with acute myocardial ischemia and after coronary angioplasty. BACKGROUND: The calcium sensitizer levosimendan improves the function of myocardium in experimental stunning. METHODS: Twenty-four patients with an acute coronary syndrome underwent angioplasty followed by double-blinded, randomized treatment ...
Grieve David J - - 2004
The development of microconductance technology to study cardiac pressure-volume relations in mice in vivo has significantly advanced the haemodynamic assessment of gene-modified models of cardiovascular disease. In this study, we describe the application of microconductance analysis of cardiac function to the isolated murine ejecting heart. This ex vivo model is ...
Pearson James T - - 2004
BACKGROUND: Synchrotron radiation has been used to analyze crossbridge dynamics in isolated papillary muscle and excised perfused hearts with the use of x-ray diffraction techniques. We showed that these techniques can detect regional changes in rat left ventricle contractility and myosin lattice spacing in in situ ejecting hearts in real ...
Takaki M - - 2004
Studies on left ventricular mechanical work and energetics in rat and mouse hearts are reviewed. First, left ventricular linear end-systolic pressure-volume relation (ESPVR) and curved end-diastolic pressure-volume relation (EDPVR) in canine hearts and left ventricular curved ESPVR and curved EDPVR in rat hearts are reviewed. Second, as an index for ...
Di Donato Marisa - - 2004
BACKGROUND: In ischemic cardiomyopathy, dyssynchrony of left ventricular (LV) mechanical contraction produces adverse hemodynamic consequences. This study tests the capacity of geometric rebuilding by surgical ventricular restoration (SVR) to restore a more synchronous contractile pattern after a mechanical, rather than electrical, intervention. METHODS AND RESULTS: A prospective study of the ...
Lips Daniel J - - 2004
OBJECTIVE: We investigated whether in vivo closed-chest left ventricular pressure-volume measurements would yield similar values for LV hemodynamics compared with open-chest PV measurements under several anesthetics. METHODS: The right common carotid of C57Bl/6 mice was cannulated with a combined pressure-conductance catheter and inserted retrogradely into the left ventricle in the ...
Kumar Anand - - 2004
OBJECTIVE: Characterize the normal human cardiovascular response to large volume infusion of normal saline. DESIGN: Prospective, interventional trial. SETTING: ICU procedure room. PARTICIPANTS: Healthy male volunteers ( n=32). INTERVENTIONS. Volumetric echocardiography during 4-L saline infusion (3 L over 3 h followed by 1 L over 2 h). MEASUREMENTS AND RESULTS: ...
Kumar Anand - - 2004
Resuscitation with saline is a standard initial response to hypotension or shock of almost any cause. Saline resuscitation is thought to generate an increase in cardiac output through a preload-dependent (increased end-diastolic volume) augmentation of stroke volume. We sought to confirm this to be the mechanism by which high-volume saline ...
Karamanoglu Mustafa - - 2004
Ventricular function has conventionally been characterized using indexes of systolic (contractile) or diastolic (relaxation/stiffness) function. Systolic indexes include maximum elastance or equivalently the end-systolic pressure volume relation and left ventricular ejection fraction. Diastolic indexes include the time constant of isovolumic relaxation - and the end-diastolic pressure-volume relation. Conceptualization of ventricular ...
Kumar Anand - - 2004
OBJECTIVE: Pulmonary artery occlusion pressure and central venous pressure have been considered to be reliable measures of left and right ventricular preload in patients requiring invasive hemodynamic monitoring. Studies in recent years have questioned the correlation between these estimates of ventricular filling pressures and ventricular end-diastolic volumes/cardiac performance variables in ...
Knez Peter - - 2004
Anastomotic configurations with a small internal diameter are prone to intimal hyperplasia which can cause occlusion within weeks or months. A link between intimal hyperplasia and inhomogenities of the elastic profile of the anastomosis has been established, making anastomotic engineering directed towards smoothing the compliance profile at the anastomotic site ...
Lunkenheimer P P - - 2004
To test the hypothesis that two populations of myocardial fibres-fibres aligned parallel to the surfaces of the wall and an additional population of fibres that extend obliquely through the wall-when working in concert produce a dualistic, self stabilising arrangement. Assessment of tensile forces in the walls of seven porcine hearts ...
Lester Steven J - - 2004
This study tested the hypothesis that the preload-adjusted maximal power index (PA-PWRmax) is a load-independent index of human myocardial contractility. Based on the ventricular pressure-volume relationship and derived from stroke work, the index is the product of instantaneous ventricular pressure and volume changes, divided by a correction term of end-diastolic ...
Lambermont Bernard - - 2004
We investigated the effects of a dual thromboxane (TX)A2 synthase inhibitor and TXA2 receptor antagonist (BM-573) on right ventricular-arterial coupling in a porcine model of endotoxic shock. Thirty minutes before the onset of 0.5 mg/kg endotoxin infusion, six pigs (Endo group) received an infusion with a placebo solution, and six ...
Lembcke Alexander - - 2004
BACKGROUND: The cardiac support device (CSD, Acorn) is a compliant, textile-mesh graft placed around the ventricles to prevent further dilatation and to improve function in congestive heart failure. The aim of this study was to verify post-operative changes in left ventricular volumes, ejection fraction, blood flow, and myocardial mass. METHODS: ...
Haithcock Benjamin E - - 2004
We tested the hypothesis that creation of a constant-flow extracorporeal circuit between the proximal and distal aorta will unload the failing left ventricle. Studies were performed in 14 heart failure dogs produced by intracoronary microembolizations. An extracorporeal circuit incorporating a diagonal pump was placed between a femoral and a carotid ...
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