Search Results
Results 251 - 300 of 1604
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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 ...
Joyce James J - - 2004
The effects of chronic volume or pressure overload on the velocity of right ventricular ejection have not been previously well defined. We hypothesized that, as formerly shown for the left ventricle, there would be a direct relationship between the velocity of ejection and an estimate of systolic wall stress. METHODS: ...
Kerkhof Peter L M - - 2004
The dynamics of the left ventricle (LV) have been extensively investigated. However, most studies refer to steady state conditions. We addressed the beat-to-beat variations resulting from hemodynamic interventions analyzed in the chronically instrumented dog. This approach permits serial studies in the same subject under physiological conditions. In particular we investigated ...
Redaelli Alberto - - 2004
Mechanics following partial left ventriculectomy is still poorly understood. A computational cylindrical model of the left ventricle was developed, based on the myocardial fibre behaviour for the evaluation of the mechanical and haemodynamical effects of the operation. A healthy left ventricle with physiological geometry and function and a dilated hypokinetic ...
Thompson Richard B - - 2003
To date, no data exist on the linearity and, therefore, the usefulness of the preload recruitable stroke work (PRSW) and end-systolic pressure-volume (ESPVR) relationships during acute afterload changes in heart failure. Our aim was, therefore, to characterize both relationships in a model of ventricular pacing induced heart failure at baseline ...
Tao Weike - - 2004
We previously showed that beta2-microglobulin knockout mice treated with anti-asialoGM1 (beta2M/alphaAsGM1 mice) exhibit less hypothermia, reduced production of proinflammatory cytokines, less metabolic acidosis, and improved survival after cecal ligation and puncture (CLP) compared with wild-type mice. The present study was designed to assess hemodynamics and left ventricular contractility at 18 ...
Folino A F - - 2003
The aim of our study was to assess the arrhythmic profile in patients with primary pulmonary hypertension (PPH) and its correlation with autonomic features, echocardiographic indexes and pulmonary function. We studied 9 subjects with a mean age of 42 +/- 11 years. All underwent echocardiography, 24-hour Holter monitoring, and cardiopulmonary ...
McKelvie Robert S - - 2003
RESOLVD study patients were randomized to candesartan (C), enalapril (E), or C+E. Patients were later randomized to metoprolol CR (M) or placebo. Examine impact of C or E (C/E), C+E, C+M/E+M, C+E+M on ventricular remodelling in heart failure (HF) over 43 weeks. Four hundred and twenty-six of 768 patients receiving ...
Atkins B Zane - - 2003
BACKGROUND: Real-time 3-dimensional echocardiography (RT3DE) reliably determines intracardiac chamber volumes without left ventricular (LV) geometric assumptions, yet clinical assessment of contractile performance is often on the basis of potentially inaccurate, load-dependent indices such as ejection fraction. METHODS: In 6 chronically instrumented dogs, RT3DE estimated LV volumes at various loading conditions. ...
Suga Hiroyuki - - 2003
1. To celebrate this Festschrift for Professor Colin Gibbs, as an invited speaker, I would like to review briefly my 35 year research career in cardiac physiology. 2. My career started in the late 1960s in Tokyo with my serendipitous discovery of Emax (ventricular end-systolic maximum elastance) as a load-independent ...
Chen Chen-Huan - - 2003
The importance of volume status on blood pressure in hemodialysis patients has long been recognized. We hypothesized that the enhanced volume dependency of blood pressure is partly determined by ventricular stiffness at end systole. A total of 115 long-term hemodialysis patients were invited to receive a comprehensive, noninvasive cardiovascular examination. ...
Müller Silvana - - 2003
BACKGROUND: Tissue Doppler (TD) analysis is used to estimate contractility. However, interference with hemodynamics has not been investigated. OBJECTIVE: To evaluate the effect of hemodynamic conditions and wall motion abnormalities on TD indices. METHODS: TD indices were obtained in 16 dogs and correlated with hemodynamics and wall thickening. RESULTS: An ...
Milicević Goran - - 2003
Pubertal growth of heart was analyzed. Growth rates of "diastolic variables" of heart size were compared with that of 'systolic', and both with growth intensities of some body structures and functions that are related to cardiac growth. Longitudinal echocardiographic, ergometric and anthropometric measurements were performed in 84 healthy boys, aged ...
Reyes Maricela - - 2003
BACKGROUND: It has been hypothesized that because of its rapid heart rate, the intact murine heart functions near maximal contractility in the basal state. If this hypothesis is correct, then the fast and slow components of myocardial length-dependent activation should be blunted compared with larger mammals. METHODS AND RESULTS: Mice ...
Correia-Pinto J - - 2003
This study investigated potential differences on load dependence of relaxation rate and diastolic function between Oryctolagus cuniculus and Ratus norvegicus, which have constitutive differences in the mechanisms involved in myocardial inactivation. Load dependence of relaxation rate and diastolic function were evaluated with the response of left ventricular time constant tau ...
Leeper Barbara - - 2003
The resuscitation of critically ill patients frequently requires the administration of fluids for the purpose of increasing cardiac output and oxygen delivery to the tissues. The assessment of the patient's preload status during this process is vital. Traditionally, preload assessment has been through the use of right atrial pressure and ...
Arts T - - 2003
Complexity of the geometry and structure of the heart hampers easy modeling of cardiac mechanics. The modeling can however be simplified considerably when using the hypothesis that in the normal heart myofiber structure and geometry adapt, until load is evenly distributed. A simple and realistic relationship is found between the ...
Suga Hiroyuki - - 2003
This review on the global cardiac function covers cardiac mechanics, energetics, and informatics that I have developed with my collaborators over the last 30 years in Japan and USA. We first established E(max) (end-systolic maximum elastance or pressure/volume ratio) as a new index of ventricular contractility using canine hearts. We ...
LaCorte Jared C - - 2003
BACKGROUND: The Doppler myocardial performance (Tei) index has been reported to be clinically useful in assessing left ventricular systolic and diastolic function in both adults and children. However, there are limited data to compare the Tei index with invasive measurements of ventricular function. We used a porcine model to directly ...
Sellgren J - - 2003
BACKGROUND: Assessment of preload independent left ventricular function with conductance volumetry is traditionally accomplished by inflating a balloon in the inferior caval vein. Our aim was to investigate if a similar change in preload could be achieved by positive pressure ventilation with large tidal volume. METHODS: Conductance volumetry generating left ...
Szabó Gábor - - 2003
OBJECTIVE: Fontan-type operations offer the opportunity to create pulmonary and systemic circulation in series with a single pumping chamber. The effectiveness of such a circulatory pattern determines resting and exercise hemodynamics in these patients. The present study investigated cardiac performance after the Fontan operation by using ventricular-vascular coupling framework analysis. ...
Chemla Denis - - 2003
The respective contribution of systemic vascular resistance (R) and total arterial compliance (C) to the arterial load remains to be established in humans. Effective arterial elastance (Ea), i.e., the left ventricular end-systolic pressure (LVESP)-over-stroke volume ratio, is a reliable estimate of arterial load. It is widely accepted that Ea mainly ...
Khongphatthanayothin Apichai - - 2003
OBJECTIVE: To study left ventricular performance and hemodynamic abnormalities during different stages of dengue hemorrhagic fever (DHF). DESIGN AND SETTING: Observational study in a tertiary medical school hospital. PATIENTS: Twenty-four patients with serologically confirmed diagnosis of dengue virus infection and DHF according to the WHO criteria. METHODS: Echocardiography was performed ...
Kawaguchi Miho - - 2003
BACKGROUND: Heart failure with preserved ejection fraction (HF-nlEF) is common in aged individuals with systolic hypertension and is frequently ascribed to diastolic dysfunction. We hypothesized that such patients also display combined ventricular-systolic and arterial stiffening that can exacerbate blood pressure lability and diastolic dysfunction under stress. METHODS AND RESULTS: Left ...
Bertolissi Massimo - - 2003
The aim of the present study was to evaluate the haemodynamic effects of passive leg elevation on the right ventricular function in two groups of patients, one with a normal right ventricular ejection fraction (RVEF) and one with a reduced RVEF. Twenty coronary patients undergoing elective coronary artery bypass grafting ...
Kashem Abul - - 2003
OBJECTIVE: We tested whether the CardioClasp device (CardioClasp, Inc, Cincinnati, Ohio), a non-blood contact device, would improve left ventricular contractility by acutely reshaping the left ventricle and reducing left ventricular wall stress. METHODS: In dogs (n = 6) 4 weeks of ventricular pacing (210-240 ppm) induced severe heart failure. Left ...
Michelfelder Erik C - - 2003
BACKGROUND: Assessment of ventricular contractile reserve by dobutamine stress echocardiography (DSE) may be a powerful tool for detection of subclinical ventricular dysfunction, however, the hemodynamic dose-response relationship during DSE in children has not been established. METHODS: To characterize changes in hemodynamics and ventricular contractility during DSE in children, 26 participants ...
Moran Adrian M - - 2003
BACKGROUND: The determination of progression from afterload mismatch to myocardial failure in small animals requires invasive monitoring to assess ventricular pressure. OBJECTIVE: We sought to (1) validate the noninvasive determination of blood pressure using optical plethysmography, and (2) determine the time course and progression from afterload mismatch to myocyte failure ...
Morita Shigeki - - 2003
OBJECTIVES: Few data have been available regarding the immediate response in ventricular mechanics to acute volume reduction caused by aortic valve replacement for aortic regurgitation. METHODS: We studied 9 patients in the operating room immediately before and after the institution of cardiopulmonary bypass. Left ventricular pressure and cross-sectional area (a ...
Carrington Russell A J - - 2003
BACKGROUND: In failing hearts, homeostatic mechanisms contrive to maximize stroke work and maintain normal arterial blood pressure at the expense of energetic efficiency. In contrast dobutamine reestablishes maximal mechanical efficiency by promoting energetically optimal loading conditions. However, dobutamine also wastefully increases nonmechanical oxygen consumption. We investigated whether direct mechanical cardiac ...
Nozaki J - - 2003
BACKGROUND: Acute normovolemic hemodilution (ANH) causes a decrease in systemic vascular resistance. Similar to vasodilating drugs, ANH might modify ventriculoarterial coupling. Left ventricular elastance (Ees), effective arterial elastance (Ea), stroke work (SW), and pressure volume area (PVA) were used as indicators to examine the effects of ANH on this coupling. ...
Ryan Jonathon B - - 2002
OBJECTIVE: Paradoxically, it has been reported that after 1.5-4 h of hypothermic ischaemic preservation there is complete recovery of contractile function in canine cardiac allografts, as assessed by the preload recruitable stroke work (PRSW) relationship. This raises questions about the suitability of the canine heart as a model for preservation ...
Harada K - - 2002
Dobutamine stress echocardiography has become accepted in the evaluation of cardiac functional reserve. Although the Doppler-derived index of combined systolic/diastolic myocardial performance (Tei index) has been reported to be easily obtainable and useful for predicting left ventricular performance, the effect of dobutamine on the Tei index has not been determined ...
Tiemann Klaus - - 2003
Knowledge of the developmental changes of cardiovascular parameters in the genetic background of a mouse strain is important for understanding phenotypic changes in transgenic or knockout mouse models for heart disease. We studied arterial blood pressure and myocardial contractility in mice of the common background strain C57BL/6, aged 21 days ...
Suzuki T T Division of Nephrology and Endocrinology, The University of Tokyo School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan Tel. +81-3-5800-9735; Fax +81-3-5800-9736 e-mail: fujita-dis@h.u-tokyo.ac.jp, - - 2002
We describe a 19-year-old man who developed muscle weakness due to hypokalemia. His blood pressure on admission was considered to be relatively high, and we performed captopril renography. His baseline renogram was normal, while the results of captopril renography showed delayed patterns similar to those of renovascular hypertension. However, his ...
Haney Michael F - - 2002
BACKGROUND: A graded preload reduction during analysis of the left ventricular pressure-volume relationship (LVPVR) is required for derivation of end-systolic elastance (Ees) and preload recruitable stroke work (PRSW). The authors aimed to measure serial changes in these systolic function parameters before and during planned circulatory interventions using two different methods ...
Gallup Cecily J - - 2002
BACKGROUND: Real-time measurement of left ventricular end-diastolic volume (LVEDV), combined with left ventricular end-diastolic pressure (LVEDP), would allow continuous measurement of intraoperative diastolic function. In pursuit of this goal, we examined stroke volume divided by ejection fraction for calculation of LVEDV(sv/ef). METHODS: Five anesthetized pigs underwent median sternotomy and pericardiotomy. ...
Hansen J - - 2002
In the mammalian heart the metabolic costs of pressure loading exceed those of volume loading. As evidence suggests that the opposite may be true in fish, we evaluated the metabolic costs of volume and pressure loading in the isolated trout heart and compared the results with the mammalian heart based ...
Saavedra W Federico - - 2002
OBJECTIVES: We sought to test the efficacy of a passive elastic containment device to reverse chronic chamber remodeling and adrenergic down-regulation in the failing heart, yet still maintaining preload reserve. BACKGROUND: Progressive cardiac remodeling due to heart failure is thought to exacerbate underlying myocardial dysfunction. In a pressure-volume analysis, we ...
Martin David S - - 2002
BACKGROUND: Previous echocardiographic studies of astronauts before and after short-duration (4-17 d) missions have demonstrated a decrease in resting left ventricular stroke volume, but maintained ejection fraction (EF) and cardiac output. Similar studies before and after long-duration (129-144 d) spaceflight have been rare and their overall results equivocal. METHODS: Echocardiographic ...
Du Wenhua - - 2002
OBJECTIVE: To study changes and rules of the left ventricular functions in rabbits with myocardial contusion through parallel functional analysis by using echocardiography combined with cardiac catheter intervention. METHODS: Thirty healthy rabbits were selected and impacted to make moderate or severe myocardial contusion by BIM-II biomedical impact machine. The changes ...
Preisman S - - 2002
BACKGROUND: Arterial pressure waveform analysis is a new method for assessment of cardiac preload. Despite the close correlation of parameters derived by its use with the degree of blood loss, their relationship with more precise estimates of cardiac preload remains controversial. METHODS: Systolic pressure variation (SPV), delta up (dUp), and ...
Kjørstad Knut E - - 2002
The end-systolic pressure-volume relationship is regarded as a useful index for assessing the contractile state of the heart. However, the need for preload alterations has been a serious limitation to its clinical applications, and there have been numerous attempts to develop a method for calculating contractility based on one single ...
Mohri Satoshi - - 2002
Inotropic effects of electric currents applied during the refractory period have been reported in cardiac muscle in vitro using voltage-clamp techniques. We investigated how electric currents modulate cardiac contractility in normal canine hearts in vivo. Six dogs were instrumented to measure regional segment length, ventricular volume (sonomicrometry), and ventricular pressure. ...
Takagaki Masami - - 2002
OBJECTIVE: An animal model of chronic severe heart failure is needed to evaluate new mechanical devices, surgical procedures, and medical therapies. The purpose of this study was to evaluate a unique new model of severe heart failure developed by means of a novel protocol of rapid ventricular pacing. METHODS: Heart ...
Menzel T - - 2002
AIMS: Evaluation of a three-dimensional reconstruction method to show the changes of right ventricular volume and systolic function when patients undergo pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension. METHODS AND RESULTS: In the examination of 11 patients (four female, seven male; age 56+/-10 years) before and after pulmonary thromboendarterectomy, end-diastolic ...
Wronski T - - 2002
Optimal ventriculoaortic coupling includes tuning of elastic properties. The ratio of effective arterial elastance and left ventricular endsystolic elastance is often taken as a measure for mechanical and energetical efficiency. The present study determined the time course of ventricular and aortic volume elasticity (VE = dp/dV) throughout a complete heartbeat. ...
Shirota Kazuaki - - 2002
BACKGROUND: Dynamic cardiomyoplasty (d-CMP) encourages reverse remodeling and improved contractility and stroke work (SW) efficiency of the failing native heart. This contrasts with passive cardiomyoplasty (p-CMP), which provides "passive girdling." To further evaluate pump recovery we assessed native left ventricular performance (without assist) 6 months after dynamic and passive CMP ...
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