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Etemadi Mozziyar M Department of Electrical Engineering, Stanford University, Stanford, CA, - - 2009
Myocardial contractility, the intrinsic ability of the heart muscle to produce force, has been difficult to quantify non-invasively. Pre-ejection-period (PEP), the time the ventricles spend in isovolumetric contraction, is widely accepted as a way to measure contractility. This work presents a way by which the ballistocardiogram - a readily accessible ...
Black Adam A Medtronic, Inc., Mounds View, MN 55112, - - 2009
Intracellular regulation of myocardial Ca2+ has long been of interest to physiologists. The force-interval relationship provides a phenomenological approach that permits insight into aspects of calcium regulation. The response to an extrasystole is a potentiation in contractile force and the recovery in contractile force is described by the recirculation fraction ...
Nguyen Mai-Dung MD Department of Bioengineering, University of Louisville, Louisville, KY 40208, - - 2009
Physiological heart development and cardiac function rely on the response of cardiomyocytes to mechanical stress signals during hemodynamic loading and unloading. These stresses manifest themselves via changes in cell structure, contractile function and gene expression. Disruption of this well balanced stress-sensing machinery due to various pathological conditions results in contractile ...
Patangay Abhilash A Boston Scientific Corp., St. Paul, MN, USA. - - 2009
Acute myocardial infarction (AMI) is one of the leading causes of death in the US. While heart rate variability (HRV) has been widely studied for ischemia detection, the changes in cardiac contractility variability have not yet been explored. This paper presents novel variability analysis using 23 linear and non-linear measures ...
Vanderschuren Abel - - 2009
The authors describe the clinical course of a 50-year-old woman who presented with life-threatening cardiac dysfunction after aneurysmal subarachnoid hemorrhage (Fisher Grade 4). The pathophysiology of cardiac injury in this setting is not fully understood, but excess sympathetic activation can lead to neurogenic stressed myocardium. A metabolic intervention using the ...
Folino Antonio Franco - - 2010
Previous studies proposed as one of the main mechanisms involved in neurally mediated syncope, the stimulation of ventricular mechanoreceptors as the final trigger for vagal discharge. This study aimed to verify the presence of a sympathetic driven increase of cardiac contractility before vasovagal syncope. We studied 23 patients with recurrent ...
Zhang X-J - - 2009
BACKGROUND: Several studies have demonstrated the inhibitory effect of propofol on diaphragmatic contractility in laboratory animals, but there have been few studies in humans. We have investigated the effect of a single bolus injection of propofol on twitch diaphragmatic pressure (TwPdi) evoked by cervical supramaximal magnetic stimulation, and its impact ...
Ramirez-Correa Genaro A GA Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Md., - - 2008
In addition to O-phosphorylation, O-linked modifications of serine and threonine by beta-N-acetyl-D-glucosamine (GlcNAc) may regulate muscle contractile function. This study assessed the potential role of O-GlcNAcylation in cardiac muscle contractile activation. To identify specific sites of O-GlcNAcylation in cardiac myofilament proteins, a recently developed methodology based on GalNAz-biotin labeling followed ...
Irvine Jennifer C - - 2008
Until recently, most of the biological effects of nitric oxide (NO) have been attributed to its uncharged state (NO*), yet NO can also exist in the reduced state as nitroxyl (HNO or NO(-)). Putatively generated from both NO synthase (NOS)-dependent and -independent sources, HNO is rapidly emerging as a novel ...
Barber Robert C - - 2008
Burn injury has been associated with systemic/compartmental inflammatory responses and myocardial dysfunction. We hypothesized that burn size correlates with the extent of cardiac inflammatory response/contractile dysfunction. Adult male Sprague-Dawley rats were divided to receive anesthesia, a 3-degree burn covering 20%, 30%, 40%, or 60% total body surface area (TBSA) plus ...
Abraham William T - - 2008
Cardiac contractility modulation (CCM) signals are nonexcitatory electrical signals delivered during the cardiac absolute refractory period that enhance the strength of cardiac muscular contraction. Prior research in experimental and human heart failure has shown that CCM signals normalize phosphorylation of key proteins and expression of genes coding for proteins involved ...
Ojha Shreesh K - - 2008
In present study, hydroalcoholic extract of C. mukul significantly improved the cardiac function and prevented myocardial ischemic impairment manifested in the form of increased heart rate, decreased arterial pressure, increased left ventricular end diastolic pressure, and altered myocardial contractility indices. C. mukul treatment additionally also produced a significant increase in ...
Pinz Ilka I NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. - - 2008
TNFalpha is a cytokine wit pleiotropic functions in many organs. In the heart increased TNFalpha levels are not only associated with heart failure, but also, paradoxically, with protection from ischemic damage. To test whether the protective role of TNFalpha in the heart is concentration-dependent, we studied two mouse heart models ...
Heusch G - - 2008
The bradycardic agent ivabradine has proved to be of benefit in experimental models with the end points of ischaemic myocardial blood flow and contractile function, infarct size, post-infarct remodelling and atherosclerosis. The benefits to ischaemic myocardial blood flow and contractile function are strictly heart rate dependent; those on infarct size ...
Eszlári E - - 2008
The aim of this study was to outline the consequences of a hypertonic saline-dextran-40 (HSD) infusion-induced peripheral flow stimulus on the ventricular function in closed-chest, pentobarbital-anesthetized dogs. We hypothesized that HSD-induced elevation in endothelin-1 (ET-1) and nitric oxide (NO) release can have a role in myocardial contractile responses; and that ...
Ren Jun - - 2008
Compromised heart function is regularly seen in patients with chronic alcohol ingestion and is often manifested as cardiomegaly, reduced myocardial contractility (with concomitant reductions in ejection fraction and stroke volume), myocardial fibrosis, enhanced risk of stroke and hypertension, and disruptions in the myofibrillary structure. A number of mechanisms including oxidative ...
Sonin Dmitry - - 2008
Evidence is accumulating to support the presence of P2X purinergic receptors in the heart. However, the biological role of this receptor remains to be defined. The objectives here were to determine the role of cardiac P2X receptors in modulating the progression of post-myocardial infarction ischemic heart failure and to investigate ...
Sedmera David D Institute of Animal Physiology and Genetics, Prague, Czech Republic. - - 2008
This article concerns the development of myocardial architecture--crucial for contractile performance of the heart and its conduction system, essential for generation and coordinated spread of electrical activity. Topics discussed include molecular determination of cardiac phenotype (contractile and conducting), remodeling of ventricular wall architecture and its blood supply, and relation of ...
Shiels Holly A - - 2008
The Frank-Starling law of the heart applies to all classes of vertebrates. It describes how stretch of cardiac muscle, up to an optimum length, increases contractility thereby linking cardiac ejection to cardiac filling. The cellular mechanisms underlying the Frank-Starling response include an increase in myofilament sensitivity for Ca2+, decreased myofilament ...
Kassiotis Christos - - 2008
Myocardial energy substrate metabolism entails a complex system of enzyme catalyzed reactions, in which the heart efficiently converts chemical to mechanical energy. The system is highly regulated and responsive to changes in workload as well as in substrate and hormone supply to the heart. Akin to the terms "contractile reserve" ...
Khairallah M - - 2008
We recently demonstrated early metabolic alterations in the dystrophin-deficient mdx heart that precede overt cardiomyopathy and may represent an early "subclinical" signature of a defective nitric oxide (NO)/cGMP pathway. In this study, we used genetic and pharmacological approaches to test the hypothesis that enhancing cGMP, downstream of NO formation, improves ...
Blagonravov M L - - 2008
Acute coronary failure was modeled in rabbits by ligation of the descending left coronary artery at the interface of its middle and lower thirds. The function and morphology of left-ventricular and right-ventricular myocardium were studied on days 1, 3, and 5 of the pathological process. It was found that left-ventricular ...
Bedosky, Kristen Marie
The incidence of cardiovascular disease has reached epidemic proportions in North America. Specifically, myocardial infarctions (MI) are a major contributor to heart failure which greatly influences morbidity and mortality rates in developed nations. In the post-MI heart, cardiac fibroblasts migrate to the damaged area, convert to myofibroblasts and contribute to ...
Gonzalez-Muñoz Carmen - - 2008
This study evaluates the inotropic responses to glucagon in electrically driven isolated left and right atria as well as in right ventricular strips of rat heart. For comparison, the contractile effects resulting from stimulating beta-adrenoceptors with isoprenaline in atrial and ventricular tissues were also obtained. Glucagon (0.01-1 microM) produces a ...
Durgan David J - - 2008
INTRODUCTION: The energetic demands imposed upon the heart vary dramatically over the course of the day. In the face of equally commanding oscillations in the neurohumoral mileu, the heart must respond both rapidly and appropriately to its diurnal environment, for the survival of the organism. A major response of the ...
Mansouri Seyed Mohammad-Taghi - - 2008
BACKGROUND: Selective phosphodiesterase (PDE3) inhibitors improve cardiac contractility and may use in congestive heart failure. However, their proarrhythmic potential is the most important side effect. METHODS: In this research, we evaluated the potential cardiotonic activity of six new synthesized selective PDE3 inhibitors (6-hydroxy-4-methylquinolin-2(1H)-one derivatives) using the spontaneously beating atria model. ...
Doenst Torsten - - 2008
It is the principal goal of cardiac surgeons to improve or reinstate contractile function with, through or after a surgical procedure on the heart. Uninterrupted contractile function of the heart is irrevocably linked to the uninterrupted supply of energy in the form of ATP. Thus, it would appear natural that ...
Pantos Constantinos - - 2008
Thyroid hormone has various effects on the cardiovascular system and its effects on cardiac contractility, heart rhythm and vascular function has long been recognized. However, new evidence is emerged on the importance of thyroid hormone in the response of the myocardium to ischaemic stress and cardiac remodelling following myocardial infarction. ...
Bray Molly S - - 2008
The heart is challenged by a plethora of extracellular stimuli over the course of a normal day, each of which distinctly influences myocardial contractile function. It is therefore not surprising that myocardial metabolism also oscillates in a time-of-day dependent manner. What is becoming increasingly apparent is that the heart exhibits ...
Sando Ian C IC Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana, - - 2008
Tumor necrosis factor-alpha (TNF-alpha) plays a critical role in myocardial dysfunction following acute injury. It is unknown, however, if a gender-specific response to TNF infusion exists in isolated rat hearts. Elucidating such mechanisms is important to understanding the myocardial gender differences during acute injury. We hypothesize that females will exhibit ...
Lian F - - 2008
This study was designed to evaluate the long-term effect of endothelial progenitor cell (EPC) implantation in acute myocardial infarction in Sprague-Dawley rats after ligation of the left anterior descending coronary artery. Autologous EPCs from peripheral blood were purified and implanted into an acute myocardial infarct site. Specimens and muscle strip ...
Lee Marlon A - - 2008
Acute injury-induced cardiac contractile dysfunction occurs even in young and otherwise healthy individuals after major injuries, and significantly contributes to morbidity and mortality in patients with pre-existent cardiac diseases as well as in patients who develop multiple organ dysfunction syndrome. Recent studies indicate that post-injury acute cardiac failure is the ...
Moniotte S - - 2007
To analyze the implication of the beta3-adrenoceptor (beta3-AR) pathway in human septic myocardium and a murine model of sepsis, a condition associated with myocardial depression. beta3-AR and eNOS protein abundance were increased (332+/-66.4% and 218+/-39.3; P<0.05) in hearts from septic patients. The effect of BRL37344, a beta3-AR-preferential agonist, was analyzed ...
Ghanem Alexander - - 2008
Myocardial remodeling determines the degree of left ventricular dysfunction and mortality after transmural chronic myocardial infarction (CMI). Noninvasive characterization and quantitation of myocardial borderzone and collagenous scar are therefore parameters of clinical interest. The aims of this study were (i) to measure accuracy of reconstructive 3-D echocardiography (3DE) in scar ...
Smith Godfrey - - 2007
Heart failure as a result of a myocardial infarction (MI) is a common condition with a poor prognosis. The adaptive changes in the surviving myocardium appear to be insufficient in terms of both mechanical/contractile performance and electrical stability. The modification of the underlying myocardial physiology is complex, varying across the ...
Huang Q-Q - - 2008
In contrast to skeletal muscles that simultaneously express multiple troponin T (TnT) isoforms, normal adult human cardiac muscle contains a single isoform of cardiac TnT. To understand the significance of myocardial TnT homogeneity, we examined the effect of TnT heterogeneity on heart function. Transgenic mouse hearts overexpressing a fast skeletal ...
Hambleton Michael M Division of Molecular Cardiovascular Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, - - 2007
Mice null for the gene encoding protein kinase Calpha (Prkca), or mice treated with pharmacologic inhibitors of the PKCalpha/beta/gamma isoforms, show an augmentation in cardiac contractility that appears to be cardioprotective. However, it remains uncertain if PKCalpha itself functions in a myocyte autonomous manner to affect cardioprotection in vivo. Here ...
Guarracino F - - 2007
BACKGROUND: Levosimendan, a novel calcium sensitizer, enhances myocardial contractility without affecting intracellular calcium concentration. It also dilates peripheral arterial vessels by acting on ATP-dependent K(+) channels. Ventriculo-arterial coupling, the relationship between myocardial contractility and the arterial system, describes the efficiency of the cardiovascular system by analysing the relationship between myocardial ...
Smith Godfrey L - - 2007
Heart failure as a result of a myocardial infarction (MI) is a common condition with a poor prognosis. The adaptive changes in the surviving myocardium appear to be insufficient in terms of both mechanical/contractile performance and electrical stability. The modification of the underlying myocardial physiology is complex, varying across the ...
Quaile Michael P - - 2007
Myocardial contractile reserve is significantly attenuated in patients with advanced heart failure. The aim of this study was to identify mechanisms of impaired contractile reserve in a large animal model that closely mimics human myocardial failure. Progressive right ventricular hypertrophy and failure were induced by banding the pulmonary artery in ...
Stehr Sebastian N - - 2007
BACKGROUND: Levosimendan is a novel drug used for inotropic support in heart failure, but its efficacy in local anesthetic-induced myocardial depression is not known. Therefore, we investigated the effects of levosimendan on the negative inotropic response to ropivacaine in isolated heart preparations of guinea pigs. METHODS: Action potentials and force ...
Rastaldo R - - 2007
Nitric oxide (NO) participates in the control of contractility and heart rate, limits cardiac remodeling after an infarction and contributes to the protective effect of ischemic pre- and postconditioning. Low concentrations of NO, with production of small amounts of cGMP, inhibit phosphodiesterase III, thus preventing the hydrolysis of cAMP. The ...
Ohta Soichiro - - 2007
BACKGROUND: Increased nitric oxide (NO) in the failing heart attenuates the myocardial contractile response to beta-adrenergic receptor stimulation. However, the physiological effects of NO on the beta-adrenergic post-receptor signaling system are unknown. The objective of the present study was to examine the effects of cardiac NO synthase (NOS) inhibition on ...
Carceles Mafía D - - 2007
BACKGROUND: Because milrinone is a widely used phosphodiesterase-3 (PDE3) inhibitor, it would be of interest to know whether it interacts with beta1- and beta2-adrenergic receptor (AR) agonists in human myocardium. OBJECTIVES: This in vitro study was conducted to test whether milrinone differentially regulates cyclic adenosine-3',5'-monophosphate (cAMP) production and to examine ...
Gupta Mahesh P MP Department of Surgery, Basic Science Division, MC5040, University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, USA. - - 2007
Myosin is a molecular motor, which interacts with actin to convert the energy from ATP hydrolysis into mechanical work. In cardiac myocytes, two myosin isoforms are expressed and their relative distribution changes in different developmental and pathophysiologic conditions of the heart. It has been realized for a long time that ...
Peisker T - - 2007
A 22-year-old woman developed an anaphylactic reaction after two hornet stings. Left-sided hemiparesis and gaze paresis were revealed after extubation 24 hours later. The vasoconstriction of the right MCA together with hypotension are the suggested pathogenetic determinants of the stroke.
Huschak G - - 2007
Chronic heart failure is known to be an important risk factor for adverse perioperative outcome in patients undergoing non-cardiac surgery. A promising new form of electric therapy is currently being used in a phase III trial in patients with severe chronic heart failure (cardiac contractility modulation). Cardiac contractility modulation is ...
Markert Michael - - 2007
INTRODUCTION: The objective of this study was to define the normal LVdP/dt (an index of myocardial contractility)-heart rate relationship in telemetered conscious dogs, primates and mini-pigs in our laboratory and to use these data as the basis for an additional parameter useful in drug safety evaluation. METHODS: Trained dogs, Rhesus ...
KODAMA, Makoto
Inotropic and lusitropic reserves of failing hearts were investigated using a stepwise intravenous dobutamine loading test in patients with chronic heart failure. The forty-one patients enrolled in this study were classified into 4 groups according to the left ventricular end-systolic volume indices (LVESVI). The left ventricular size of Group 1 ...
Epstein Frederick H - - 2007
Transgenic and knockout mice can be used to study the genes and basic mechanisms involved in heart disease, and have therefore assumed a central role in modern cardiac research. MRI and MRS techniques have recently been developed for mice that enable the quantitative or semi-quantitative in vivo assessment of cardiac ...
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