Showing papers on "Ventricle published in 2008"
TL;DR: The goal of the present review is to offer a clinical perspective on RV structure and function, using echocardiography and magnetic resonance imaging to create new opportunities for the study of RV anatomy and physiology.
Abstract: In 1616, Sir William Harvey was the first to describe the importance of right ventricular (RV) function in his seminal treatise, De Motu Cordis : “Thus the right ventricle may be said to be made for the sake of transmitting blood through the lungs, not for nourishing them.”1,2 For many years that followed, emphasis in cardiology was placed on left ventricular (LV) physiology, overshadowing the study of the RV. In the first half of the 20th century, the study of RV function was limited to a small group of investigators who were intrigued by the hypothesis that human circulation could function adequately without RV contractile function.3 Their studies, however, were based on an open pericardial dog model, which failed to take into account the complex nature of ventricular interaction. In the early 1950s through the 1970s, cardiac surgeons recognized the importance of right-sided function as they evaluated procedures to palliate right-heart hypoplasia. Since then, the importance of RV function has been recognized in heart failure, RV myocardial infarction, congenital heart disease and pulmonary hypertension. More recently, advances in echocardiography and magnetic resonance imaging have created new opportunities for the study of RV anatomy and physiology.
The goal of the present review is to offer a clinical perspective on RV structure and function. In the first part, we discuss the anatomy, physiology, aging, and assessment of the RV. In the second part, we discuss the pathophysiology, clinical importance, and management of RV failure.
### Macroscopic Anatomy of the RV
In the normal heart, the RV is the most anteriorly situated cardiac chamber and lies immediately behind the sternum. In the absence of transposition of great arteries, the RV is delimited by the annulus of the tricuspid valve and by the pulmonary valve. As suggested by Goor and Lillehi,4 the RV can be described in …
1,292 citations
TL;DR: Fibrosis and wall thickness were both multivariate predictors of lower segmental longitudinal strain and myocardial fibrosis is associated with depressed longitudinal strain in patients with HCM.
Abstract: The relationship among myocardial fibrosis, segmental strains, and hypertrophic cardiomyopathy (HCM) in patients with preserved left ventricular ejection fraction is not known. We evaluated this relationship in 39 consecutive patients with HCM with transthoracic echocardiography and delayed hyperenhancement magnetic resonance imaging 20 minutes after injection of 0.2 mmol/kg of gadolinium. Speckle tracking echocardiography was used to assess left ventricle strains. Fibrosis was determined semiautomatically with magnetic resonance imaging, using a 12-segment short-axis left ventricular model. Myocardial fibrosis was detected in 23 of 39 patients with HCM. The mean end-systolic longitudinal strain correlated with the number of fibrotic segments ( r = 0.47, P = .002) and total myocardial fibrosis ( r = 0.46, P = .003). Fibrosis and wall thickness were both multivariate predictors of lower segmental longitudinal strain ( P .003). Longitudinal, circumferential, and radial strains are decreased in patients with HCM even in the absence of fibrosis. Myocardial fibrosis is associated with depressed longitudinal strain in patients with HCM.
227 citations
TL;DR: Some of the challenges encountered in the measurement of RV volume and function in the context of the RV’s unique anatomic structure and physiology are discussed.
Abstract: Not long ago the right ventricle (RV) was considered an “unnecessary” part of the normal circulation. While factually correct—ablation or replacement of the RV free wall can be well tolerated by experimental animals without reduction in cardiac output, and many surgical algorithms for congenital heart diseases culminate in a circulation devoid of a sub-pulmonary ventricle, a Fontan procedure, for example—it is clear that such circulations are far from normal. Furthermore, recent studies consistently demonstrate a central role for RV dysfunction in the prognosis and outcomes for a wide variety of acquired and congenital cardiac conditions. Consequently there has been a renewed interest in the singular role of the RV, as well as its influence on global function via biventricular interactions. In this review, we will discuss some of the challenges encountered in the measurement of RV volume and function in the context of the RV’s unique anatomic structure and physiology.
The role of both ventricles is to propel blood forward in the circulation. To enable this mechanical role, ventricular function is intimately related to ventricular structure. However, the two ventricles differ. Morphologically, the RV is distinguished from the left ventricle (LV) by having coarser trabeculae, a moderator band, and a lack of fibrous continuity between its inlet and outflow valves. In the RV the pulmonary valve sits on a freestanding muscular infundibulum and the crista supraventricularis courses between it and the tricuspid valve to aid free wall contraction toward the interventricular septum. Because it normally operates at a lower pressure than the LV, the RV has a thinner wall. Its septal contour is indented by the dominant LV, producing a shape that is difficult to model geometrically (fig 1).
Figure 1 Three dimensional reconstructions of the right ventricle (RV) illustrating its complex shape in a normal subject (A). RV remodelling in diseased hearts can result in profound shape change, as in this patient (B) with dilated RV due to severe pulmonary regurgitation following repair of tetralogy of Fallot. The mesh surface is the left ventricle. LV, left ventricle; P, pulmonary valve; RV, right ventricle; T, tricuspid valve. See Sheehan and Bolson14 for explanation of reconstruction method.
Nearly all studies of ventricular fibre structure were performed on the LV.1 Dissection studies showed that its fibres course …
221 citations
TL;DR: The development of an endurancetrained heart and a strength-trained heart should not be considered an absolute concept, as both forms of training cause specific morphological changes in the heart, dependent on the type of sport.
Abstract: Cardiac remodelling is commonly defined as a physiological or pathological state that may occur after conditions such as myocardial infarction, pressure overload, idiopathic dilated cardiomyopathy or volume overload. When training excessively, the heart develops several myocardial adaptations causing a physiological state of cardiac remodelling. These morphological changes depend on the kind of training and are clinically characterised by modifications in cardiac size and shape due to increased load. Several studies have investigated morphological differences in the athlete’s heart between athletes performing strength training and athletes performing endurance training. Endurance training is associated with an increased cardiac output and volume load on the left and right ventricles, causing the endurance-trained heart to generate a mild to moderate dilatation of the left ventricle combined with a mild to moderate increase in left ventricular wall thickness. Strength training is characterised by an elevation of both systolic and diastolic blood pressure. This pressure overload causes an increase in left ventricular wall thickness. This may or may not be accompanied by a slight raise in the left ventricular volume. However, the development of an endurancetrained heart and a strength-trained heart should not be considered an absolute concept. Both forms of training cause specific morphological changes in the heart, dependent on the type of sport. (Neth Heart J 2008;16:129-33.)
217 citations
TL;DR: In this article, the authors present a non-linear 1D model of coronary and systemic arterial circulations, as well as ventricular pressure and an aortic valve that opens and closes independently based on local haemodynamics.
Abstract: There is an important interaction between the pumping performance of the ventricle, arterial haemodynamics and coronary blood flow. While previous non-linear 1D models have focused only on one of these components, the model presented in this study includes coronary and systemic arterial circulations, as well as ventricular pressure and an aortic valve that opens and closes ‘independently’ and based on local haemodynamics. The systemic circulation is modelled as a branching network of elastic tapering vessels. The terminal element applied at the extremities of the network is a single tapering vessel which is shown to adequately represent the input characteristics of the downstream vasculature. The coronary model consists of left and right coronary arteries which both branch into two ‘equivalent’ vessels that account for the lumped characteristics of subendocardial and subepicardial flows. As contracting heart muscle causes significant compression of the subendocardial vessels, a time-varying external pressure proportional to ventricular pressure is applied to the distal part of the equivalent subendocardial vessel. The aortic valve is modelled using a variable reflection coefficient with respect to backward-running aortic waves, and a variable transmission coefficient with respect to forward-running ventricular waves. A realistic ventricular pressure is the input to the system; however, an afterload-corrected ventricular pressure is calculated and results in pressure gradients between the ventricle and aorta that are similar to those observed in vivo. The 1D equations of fluid flow are solved using the locally conservative Galerkin method, which provides explicit element-wise conservation, and can naturally incorporate vessel branching. Each component of the model is verified using a number of tests to ensure accuracy and reveal the underlying processes that give rise to complex pressure and flow waveforms. The complete model is then implemented, and simulations are performed with input parameters representing ‘at rest’ and exercise states for a normal adult. The resulting waveforms contain all of the important features seen in vivo, and standard measures of haemodynamic state are found to be normal. In addition, one or several characteristics of some common diseases are imposed on the model and are found to produce haemodynamic changes that agree with experimental observations in the published literature. Using a patient-specific carotid bifurcation geometry, 1D velocity waveforms are also compared with waveforms obtained from a three-dimensional model. The 1D and 3D results show good agreement. Copyright © 2008 John Wiley & Sons, Ltd.
213 citations
TL;DR: Because the MR in this case is not the primary problem, the indications for mitral valve intervention are less certain and considerably more data are needed to aid in selecting the most appropriate patients for surgical therapy.
212 citations
TL;DR: The rationale for the use of measurements of LV size and function as guides to the management of patients with MR is reviewed, and the evolution from a compensated to a decompensated state will be discussed.
Abstract: Mitral regurgitation (MR) burdens the left ventricle with a volume load that leads to a series of left ventricular (LV) compensatory adaptations and adjustments that vary considerably during the prolonged clinical course of MR.1–4 The early compensatory changes observed in acute MR (ie, utilization of the Frank-Starling mechanism) are gradually replaced by a chronic remodeling process with enlargement of the LV chamber. Eventually, these compensatory adaptations fail, LV dysfunction develops, and transition to a decompensated phase of chronic MR occurs (Table). In the present report, the LV response to MR will be described, the evolution from a compensated to a decompensated state will be discussed, and the therapeutic implications of these events will be considered. Published guidelines provide detailed recommendations for the evaluation and treatment of patients with MR, including those with a variety of comorbidities.5,6 The present review is limited to a discussion of the changes in LV size and function that develop as a result of degenerative disease of the mitral valve (recognized clinically as severe mitral valve prolapse with or without partial flail leaflet) or, less commonly, rheumatic mitral valve disease. Our primary goal is to review the rationale for the use of measurements of LV size and function as guides to the management of patients with MR.
View this table:
Table. LV Structure and Function in the 3 Stages of Chronic MR
The clinical impact of MR is determined by the magnitude of the regurgitant leak (ie, the regurgitant volume) and the time course of development of the regurgitation. Patients with the abrupt onset of severe MR generally present with markedly elevated pulmonary venous pressure, whereas those with chronic MR exhibit prominent ventricular enlargement with increased chamber compliance and lower pulmonary venous pressure.2,7 In this section, the determinants of regurgitant flow will be defined and the …
203 citations
TL;DR: The choice of method for systemic RV cavity delineation significantly affected volume measurements, given the CMR acquisition and analysis systems used.
Abstract: Background
The method used to delineate the boundary of the right ventricle (RV), relative to the trabeculations and papillary muscles in cardiovascular magnetic resonance (CMR) ventricular volume analysis, may matter more when these structures are hypertrophied than in individuals with normal cardiovascular anatomy. This study aimed to compare two methods of cavity delineation in patients with systemic RV.
181 citations
TL;DR: A distinct syndrome of VT arising from the base of the posterior papillary muscle in the LV by a nonreentrant mechanism is presented and irrigated ablation may be necessary for long-term success.
Abstract: Background Several distinct forms of focal ventricular tachycardia (VT) from the left ventricle (LV) have been described. We report a new syndrome of VT arising from the base of the posterior papillary muscle in the LV. Methods and results Among 290 consecutive patients who underwent ablation for VT or symptomatic premature ventricular complexes (PVCs) based on a focal mechanism, 7 patients were found to have an ablation site at the base of the posterior papillary muscle in the LV. All patients had normal LV systolic function and a normal baseline electrocardiogram. The electrocardiogram during VT or PVCs demonstrated a right bundle-branch block and superior-axis QRS morphology in all patients. VT was not inducible by programmed atrial or ventricular stimulation. In 2 patients with sustained VT, overdrive pacing neither terminated VT nor demonstrated any criterion for transient entrainment. Activation mapping localized the earliest site of activation to the base of the posterior papillary muscle in all patients. When Purkinje potentials were recorded at the site of successful ablation, these potentials preceded local ventricular muscle potentials during sinus rhythm. During VT or PVCs, however, the ventricular muscle potential always preceded the Purkinje potentials. After recurrence of VT or PVCs with standard radiofrequency ablation, irrigated ablation was successful in eliminating the arrhythmia in all patients. Over a mean follow-up period of 9 months, all patients have been free of PVCs and VT. Conclusions We present a distinct syndrome of VT arising from the base of the posterior papillary muscle in the LV by a nonreentrant mechanism. Ablation can be challenging, and irrigated ablation may be necessary for long-term success.
179 citations
TL;DR: This review will focus on the pathophysiology of acute right ventricular failure in the critical care setting and summarize the limited management options available.
Abstract: Right ventricular failure may be defined as the inability of the right ventricle of the heart to provide adequate blood flow through the pulmonary circulation at a normal central venous pressure. Critical care specialists encounter right ventricular failure routinely in their practice, but until recently right ventricular failure as a primary clinical entity received scant consideration. Indeed, there is still not a single published practice guideline focused on right ventricular failure. Right ventricular failure is usually due to a combination of right ventricular pressure overload and contractile abnormalities of the right ventricular free wall. Decompensation may occur abruptly and catastrophically because of unique aspects of right ventricular physiology. This review will focus on the pathophysiology of acute right ventricular failure in the critical care setting and summarize the limited management options available.
170 citations
TL;DR: Noninvasive mapping of cardiac sympathetic nerve terminals reveals regionally impaired catecholamine uptake and storage in the normally perfused borderzone after experimental myocardial infarction.
TL;DR: The anatomic features of the LV ostium and the electrocardiographic, electrophysiological, and angiographic characteristics that are relevant to the mapping and ablation of these arrhythmias are described.
Abstract: Received June 17, 2008; accepted September 4, 2008.
Idiopathic ventricular arrhythmias (VAs) arising from the left ventricle (LV) are often accessible for catheter ablation from the aortic sinuses of Valsalva or adjacent to the mitral annulus (MA).1 The aortic and mitral valves are direct apposition and attach to an elliptical opening at the base of the LV known as the LV ostium.2 The VAs arising from this region are being increasingly recognized as targets for catheter ablation.3–7 This review describes the anatomic features of the LV ostium and the electrocardiographic, electrophysiological, and angiographic characteristics that are relevant to the mapping and ablation of these arrhythmias.
The dominant central structure of the heart is the junction of the aorta with the LV. Fundamental for understanding idiopathic VAs arising near the aortic and mitral valves are 2 concepts: first, these arrhythmias arise from the LV ostium (Figure 1); and second, the LV ostium is covered by the aorto-ventricular membrane, a tough fibrous structure which is perforated by the aorta anteriorly and the mitral valve (MV) posteriorly (Figure 2). The anatomic concept of the LV ostium and its covering, the aorto-ventricular membrane, are based on the pioneering work of McAlpine.2
Figure 1. The left ventricular ostium (postero-cranial view). The left panel includes the aortic root with the right coronary sinus (R), left coronary sinus (L), and noncoronary sinus (N). In the right panel, the root of the aorta has been removed to demonstrate the elliptical ostium of the left ventricle (LV) with the junction of the right coronary cusp (RCC), left coronary cusp (LCC), and LV summit demonstrated. APM indicates anterior papillary muscle; LA, left atrium; LAFT, left anterior fibrous trigone; LFT, left fibrous trigone; L-RCC, the junction between the LCC and RCC; PPM, posterior papillary muscle; PSP, postero-superior …
TL;DR: In this paper, the long-term liver and cardiac function after Fontan operation was assessed and a liver disease score was adopted to compare the degree of liver involvement with hemodynamic features.
TL;DR: The extent of myocardial lesions may be related to LV dysfunction and plasma BNP level in patients with cardiac sarcoidosis and their relationship to plasma brain natriuretic peptide levels and several cardiac function parameters is analyzed.
Abstract: OBJECTIVE. The objective of our study was to use MRI to analyze the topographic localization of myocardial lesions and their relationship to plasma brain natriuretic peptide (BNP) levels and several cardiac function parameters in patients with cardiac sarcoidosis.MATERIALS AND METHODS. Delayed contrast-enhanced MRI was performed in 40 patients with sarcoidosis (11 cardiac, 29 extracardiac cases). Using a 29-segment model of the left ventricle (LV), the extent of myocardial hyperenhancement was visually scored (0 = no hyperenhancement, 1 = 1–25%, 2 = 26–50%, 3 = 51–75%, 4 = 76–100% hyperenhancement) and was compared with plasma BNP level and several parameters of cardiac function.RESULTS. Ten of the 11 patients with cardiac sarcoidosis showed myocardial hyperenhancement, whereas none of the 29 patients without cardiac sarcoidosis did. In patients with cardiac sarcoidosis, hyperenhancement was significantly more extensive in basal short axis slices than in apical short axis slices (p < 0.0005). Myocardial h...
TL;DR: It is suggested that EC-SOD may act as an antioxidant in PH and that increased oxidative stress may be important in the pathogenesis of MCT-induced PH.
Abstract: Rationale: Pulmonary hypertension (PH) is a life-threatening disease, characterized by vascular remodeling and vasoconstriction Evidence suggests that oxidative stress may contribute to the pathogenesis and/or development of PHObjectives: In the present study, we examined whether intratracheal gene transfer of human extracellular superoxide dismutase (EC-SOD) could ameliorate monocrotaline (MCT)–induced PH in ratsMethods: MCT-injected rats were intratracheally administered vehicle (MCT group) or an adenovirus encoding β-galactosidase (Adβgal group) or human EC-SOD (AdEC-SOD group)Measurements and Main Results: After intratracheal gene transfer, EC-SOD was successfully expressed in lung tissue, bronchoalveolar lavage fluid, and plasma Twenty-eight days after MCT injection, right ventricular systolic pressure and the weight ratio of the right ventricle to the left ventricle plus septum were significantly lower in the AdEC-SOD group (4250 ± 146 mm Hg and 0453 ± 0029, respectively) than in the MCT gr
TL;DR: Severeleft ventricular dysfunction with associated conduction disturbances and ventricular arrhythmias occur in patients with terminal stage cardiac Fabry disease, and LVH is present and associated with thinning of the base of the left ventricular posterior wall.
TL;DR: The origin of electrophysiological heterogeneities of the adult heart lies in early heart development as discussed by the authors, which is the main mechanism of life-threatening ventricular arrhythmias, including ventricular fibrillation and tachycardia.
Abstract: Reentry is the main mechanism of life-threatening ventricular arrhythmias, including ventricular fibrillation and tachycardia. Its occurrence depends on the simultaneous presence of an arrhythmogenic substrate (a preexisting condition) and a "trigger," and is favored by electrophysiological heterogeneities. In the adult heart, electrophysiological heterogeneities of the ventricle exist along the apicobasal, left-right, and transmural axes. Also, conduction is preferentially slowed in the right ventricular outflow tract, especially during pharmacological sodium channel blockade. We propose that the origin of electrophysiological heterogeneities of the adult heart lies in early heart development. The heart is formed from several progenitor regions: the first heart field predominantly forms the left ventricle, whereas the second heart field forms the right ventricle and outflow tract. Furthermore, the embryonic outflow tract consists of slowly conducting tissue until it is incorporated into the ventricles and develops rapidly conducting properties. The subepicardial myocytes and subendocardial myocytes run distinctive gene programs from their formation onwards. This review discusses the hypothesis that electrophysiological heterogeneities in the adult heart result from persisting patterns in gene expression and function along the craniocaudal and epicardial-endocardial axes of the developing heart. Understanding the developmental origins of electrophysiological heterogeneity contributing to ventricular arrhythmias may give rise to new therapies.
01 Jan 2008
TL;DR: The main cause of morbidity and mortality in pulmonary arterial hypertension is not injury to the lung, but rather progressive right ventricular (RV) dysfunction, and the RV response to increased pulmonary afterload varies considerably between individuals, and those variations may significantly impact functional capacity and survival.
Abstract: The main cause of morbidity and mortality in pulmonary arterial hypertension (PAH) is not injury to the lung, but rather progressive right ventricular (RV) dysfunction. Although the pulmonary vasculopathy associated with PAH can impair gas exchange, patients with PAH suffer most from the inability to adequately increase cardiac output, especially during exercise. RV dysfunction in PAH is typically viewed as a secondary event, an unavoidable consequence of the progressive rise in pulmonary vascular resistance. However, the RV response to increased pulmonary afterload varies considerably between individuals, and those variations may significantly impact functional capacity and survival.
TL;DR: It is shown that Ca2+ cycling modulation using SERCA2a overexpression reduces ventricular arrhythmias after ischemia-reperfusion, whereas no significant difference was found in the occurrence of sustained or nonsustained ventricular tachycardia and ventricular fibrillation in pigs undergoing permanent occlusion.
Abstract: Background— Ventricular arrhythmias are life-threatening complications of heart failure and myocardial ischemia. Increased diastolic Ca2+ overload occurring in ischemia leads to afterdepolarizations and aftercontractions that are responsible for cellular electric instability. We inquired whether sarcoplasmic reticulum Ca2+ ATPase pump (SERCA2a) overexpression could reduce ischemic ventricular arrhythmias by modulating Ca2+ overload. Methods and Results— SERCA2a overexpression in pig hearts was achieved by intracoronary gene delivery of adenovirus in the 3 main coronary arteries. Homogeneous distribution of the gene was obtained through the left ventricle. After gene delivery, the left anterior descending coronary artery was occluded for 30 minutes to induce myocardial ischemia followed by reperfusion. We compared this model with a model of permanent coronary artery occlusion. Twenty-four–hour ECG Holter recordings showed that SERCA2a overexpression significantly reduced the number of episodes of ventricul...
TL;DR: The methodology for dynamic volumetric measurements of the mitral apparatus allows better understanding of MR mechanisms and proposes a method to determine MA area and motion throughout the cardiac cycle and to define papillary muscle position in 3-dimensional space using real-time3-dimensional echocardiography.
Abstract: Mitral regurgitation (MR) in dilated cardiomyopathy (DCM-MR) and MR in ischemic cardiomyopathy (ISC-MR) usually occurs as a result of mitral annulus (MA) dilatation and papillary muscle displacement secondary to global left ventricle remodelling. We propose a method to determine MA area and motion throughout the cardiac cycle and to define papillary muscle position in 3-dimensional space using real-time 3-dimensional echocardiography. Real-time 3-dimensional echocardiography was performed in 24 healthy individuals, and in 30 patients with DCM-MR (n = 15) or ISC-MR (n = 15). Significant intergroup differences were noted in MA surface area (control: 6.4 ± 1.7 cm 2 ; DCM-MR: 11.1 ± 2.6 cm 2 ; ISC-MR: 9.0 ± 2.0 cm 2 ) and in peak MA motion (control: 8.7 ± 3.0 mm; DCM-MR: 3.4 ± 1.7 mm; ISC-MR: 4.9 ± 1.5 mm). In patients with DCM-MR, papillary muscle symmetry was preserved, whereas in patients with ISC-MR, papillary tethering lengths were unequal as a result of wall-motion abnormalities. Our methodology for dynamic volumetric measurements of the mitral apparatus allows better understanding of MR mechanisms.
TL;DR: Behavioural testing over 6 weeks showed that acutely treated animals showed improved skilled forelimb reaching compared to penicillinase controls, and chondroitinase-treated animals showed greater axon regeneration than controls.
TL;DR: The development of a high frequency ultrasonic system for adult zebrafish cardiac imaging, capable of 75 MHz B-mode imaging at a spatial resolution of 25 microm and 45 MHz pulsed-wave Doppler measurement, offers a multitude of opportunities for cardiovascular researchers.
Abstract: The zebrafish has emerged as an excellent genetic model organism for studies of cardiovascular development. Optical transparency and external development during embryogenesis allow for visual analysis in the early development. However, to understand the cardiovascular structures and functions beyond the early stage requires a high-resolution, real-time, noninvasive imaging alternative due to the opacity of adult zebrafish. In this research, we report the development of a high frequency ultrasonic system for adult zebrafish cardiac imaging, capable of 75 MHz B-mode imaging at a spatial resolution of 25 microm and 45 MHz pulsed-wave Doppler measurement. The system allows for real-time delineation of detailed cardiac structures, estimation of cardiac dimensions, as well as image-guided Doppler blood flow measurements. In vivo imaging studies showed the identification of the atrium, ventricle, bulbus arteriosus, atrioventricular valve and bulboventricular valve in real-time images, with cardiac measurement at various stages. Doppler waveforms acquired at the ventricle and the bulbus arteriosus demonstrated the utility of this system to study the zebrafish cardiovascular hemodynamics. This high frequency ultrasonic system offers a multitude of opportunities for cardiovascular researchers. In addition, the detection of E-flow and A-flow during the ventricular filling and the appearance of diastolic flow reversal at bulbus arteriosus suggested the functional similarity of zebrafish heart to that of higher vertebrates.
TL;DR: To evaluate the long‐term follow‐up results of patients with peripartum cardiomyopathy and assess the echocardiographic findings relating to prognosis at time of diagnosis.
TL;DR: Central aortic stiffness is markedly increased and associated with increased left ventricular mass in normotensive young subjects after successful early repair of CoA.
TL;DR: The human HAND1 gene is sequenced in heart tissues derived from 31 unrelated patients diagnosed with hypoplastic hearts and a common frameshift mutation (A126fs) in the bHLH domain is detected, which is necessary for DNA binding and combinatorial interactions.
Abstract: Hypoplasia of the human heart is the most severe form of congenital heart disease (CHD) and usually lethal during early infancy. It is a leading cause of neonatal loss, especially in infants diagnosed with hypoplastic left heart syndrome (HLHS), a condition where the left side of the heart including the aorta, aortic valve, left ventricle (LV) and mitral valve are underdeveloped. The molecular causes of HLHS are unclear, but the basic helix-loop-helix (bHLH) transcription factor heart and neural crest derivatives expressed 1 (Hand1), may be a candidate culprit for this condition. The absence of Hand1 in mice resulted in the failure of rightward looping of the heart tube, a severely hypoplastic LV and outflow tract abnormalities. Nonetheless, no HAND1 mutations associated with human CHD have been reported so far. We sequenced the human HAND1 gene in heart tissues derived from 31 unrelated patients diagnosed with hypoplastic hearts. We detected in 24 of 31 hypoplastic ventricles, a common frameshift mutation (A126fs) in the bHLH domain, which is necessary for DNA binding and combinatorial interactions. The resulting mutant protein, unlike wild-type (wt) HAND1, was unable to modulate transcription of reporter constructs containing specific DNA-binding sites. Thus, in hypoplastic human hearts HAND1 function is impaired.
TL;DR: Three-dimensional echocardiography clearly showed that in the pathologic group, patients with pulmonary hypertension had the largest RV volumes and the lowest RVEF and that those with idiopathic dilated cardiomyopathy were characterized by RVEFs lower than those of patients with valvular disease.
Abstract: Right ventricular (RV) dimensions and function are of diagnostic and prognostic importance in cardiac disease. Because of the peculiar morphology of the right ventricle, 2-dimensional echocardiography has several limitations in RV evaluation. Recently, new 3-dimensional transthoracic echocardiographic software adapted for RV morphology was introduced. The aims of this study were to evaluate the feasibility of 3-dimensional RV analysis in a large population and to compare and correlate 3-dimensional RV data with classic 2-dimensional and Doppler parameters, including tricuspid annular plane systolic excursion and peak systolic velocity on Doppler tissue imaging, RV fractional shortening area, RV stroke volume (by the Doppler method), and pulmonary arterial systolic pressure. Two hundred subjects were studied: 48 normal controls and 152 patients with valvular heart disease (104 patients), idiopathic dilated cardiomyopathy (20 patients), or pulmonary hypertension (28 patients). The mean times for 3-dimensional acquisition and 3-dimensional reconstruction were 3 ± 1 and 4 ± 2 minutes, respectively. Imaging quality was good in most cases (85%). The mean RV diastolic and systolic volumes were 103 ± 38 and 46 ± 28 ml, respectively. The RV ejection fraction (RVEF) was correlated negatively with pulmonary arterial systolic pressure and positively with tricuspid annular plane systolic excursion, peak systolic velocity, and fractional shortening area. The pathologic group was characterized by larger RV volumes and lower RVEFs. Three-dimensional echocardiography clearly showed that in the pathologic group, patients with pulmonary hypertension had the largest RV volumes and the lowest RVEFs and that those with idiopathic dilated cardiomyopathy were characterized by RVEFs lower than those of patients with valvular disease. In conclusion, this new quantitative 3-dimensional method to assess RV volumes and function is feasible, relatively simple, and not time consuming. Data obtained with 3-dimensional analysis are well correlated with those obtained by 2-dimensional and Doppler methods and can differentiate normal and pathologic subjects.
TL;DR: Loss of Tbx3 affects multiple signaling pathways regulating second heart field proliferation and outflow tract morphogenesis, including fibroblast growth factor signaling, leading to a failure of normal heart tube extension and consequent atrioventricular and ventriculoarterial alignment defects.
Abstract: Conotruncal and ventricular septal congenital heart anomalies result from defects in formation and division of the embryonic outflow tract. Cardiac remodeling during outflow tract and ventricular septation converts the tubular embryonic heart into a parallel circulatory system with an independent left ventricular outlet and right ventricular inlet. Tbx3 encodes a T-box-containing transcription factor expressed in the developing conduction system of the heart. Mutations in TBX3 cause ulnar-mammary syndrome. Here we show that mice lacking Tbx3 develop severe outflow tract defects, including connection of both the aorta and pulmonary trunk with the right ventricle, in addition to aortic arch artery anomalies and abnormal communication between the right atrium and left ventricle. Alignment defects are preceded by a delay in caudal displacement of the arterial pole of the heart during aortic arch artery formation. Embryonic anterior-posterior patterning and cardiac chamber development are unaffected in Tbx3 mutant embryos. However, the contribution of second heart field derived progenitor cells to the arterial pole of the heart is impaired. Tbx3 is expressed in pharyngeal epithelia and neural crest cells in the pharyngeal region, suggesting an indirect role in second heart field deployment. Loss of Tbx3 affects multiple signaling pathways regulating second heart field proliferation and outflow tract morphogenesis, including fibroblast growth factor signaling, leading to a failure of normal heart tube extension and consequent atrioventricular and ventriculoarterial alignment defects.
TL;DR: Echocardiography does not accurately measure left ventricular hypoplasia in patients with a borderline small left ventricle and may unfairly preclude some patients from a biventricular repair in whom magnetic resonance is reassuring.
TL;DR: The dynamic changes in mitochondrial membrane potential during right ventricular hypertrophy are chamber-specific, associated with activation of NFAT, and can be pharmacologically reversed leading to improved contractility.
TL;DR: Correlations between disease severity and torsional parameters suggest a potential role of these variables in assessing early signs of ventricular dysfunction, such that early untwisting is coupled with chamber expansion.
Abstract: Background: Torsion is essential for normal systolic and diastolic function of the left ventricle (LV), and is known to be abnormal in animal models of mitral regurgitation (MR). There are no comparable data in humans. Objectives: To study LV torsion in humans with chronic primary MR using speckle-tracking echocardiography. Methods: Rotation and rotation rate were measured from two-dimensional (2D) greyscale LV base and apex short-axis images by speckle-tracking echocardiography in 38 patients and 30 controls. Using custom software, plots of torsion against time were constructed by deducting base rotation from apex rotation. Loops of torsion against LV radial/longitudinal displacement and volume were automatically plotted. Results: Peak systolic torsion, systolic torsional velocity and untwisting velocity were similar in the two groups. In controls, untwisting started 23 ms before aortic valve closure but was delayed in MR to 15 ms after aortic valve closure, p Conclusions: Chronic MR results in significant delay and slowing of LV untwisting, such that early untwisting is coupled with chamber expansion. Correlations between disease severity and torsional parameters suggest a potential role of these variables in assessing early signs of ventricular dysfunction.