Concept: Right atrium
- Current treatment options in cardiovascular medicine
- Published about 5 years ago
OPINION STATEMENT: Ebstein anomaly (EA) is a rare congenital heart defect that may not be detected until late in adolescence or adulthood. Since the original description in a 19-year-old laborer with severe tricuspid valve (TV) regurgitation in 1866, our understanding of this rare condition has increased to the recognition that it is an abnormality not only of the TV, but also of the right ventricle (RV). EA is the result of failure of delamination of the TV leaflets from the interventricular septum, resulting in adherence of the leaflets to the underlying myocardium. This results in a wide variety of abnormalities, including apical and posterior displacement of the dilated TV annulus; dilation of the “atrialized” portion of the RV; and fenestrations, redundancy, and tethering of the anterior leaflet of the TV. The malformed TV is usually regurgitant, but may rarely be stenotic. The clinical manifestations of EA in the adult depend on several factors, including the extent of TV leaflet distortion, degree of tricuspid regurgitation (TR), right atrial pressure, and presence of a right-to-left atrial level shunt. Over the past several decades, advances in diagnostic imaging and surgical techniques have contributed to our current management of this challenging congenital heart defect.
Due to the increased life expectancy and continual improvements in cardiological treatment options, diseases of the tricuspid valve, in particular tricuspid valve insufficiency will become increasingly more recognized as an interventional target. While tricuspid stenosis is rare and can be effectively treated with balloon valvuloplasty, no effective transcatheter approach to tricuspid regurgitation (TR) has yet been established. As the tricuspid annulus is a complex and highly dynamic structure that offers little resistance, orthotopic long-term fixation of transcatheter valves with the current techniques is challenging and has not yet been performed in human patients. Alternative treatment concepts include transcatheter caval valve implantation (CAVI) to address the regurgitation of blood into the caval veins, which has resulted in hemodynamic improvement and is currently undergoing further clinical investigation. Other interventional treatment concepts are aimed at tricuspid valve repair, e.g. by annular plication with the Mitralign™ device or the TriCinch™ system. In the medium-term it can be assumed that percutaneous systems and therapy options will become available for these indications whereby the functional and prognostic effects of these treatment procedures will be corroborated in the appropriate patient groups by corresponding studies.
The acknowledgment of tricuspid regurgitation (TR) as a stand-alone and progressive entity, worsening the prognosis of patients whatever its aetiology, has led to renewed interest in the tricuspid-right ventricular complex. The tricuspid valve (TV) is a complex, dynamic and changing structure. As the TV is not easy to analyse, three-dimensional imaging, cardiac magnetic resonance imaging and computed tomography scans may add to two-dimensional transthoracic and transoesophageal echocardiographic data in the analysis of TR. Not only the severity of TR, but also its mechanisms, the mode of leaflet coaptation, the degree of tricuspid annulus enlargement and tenting, and the haemodynamic consequences for right atrial and right ventricular morphology and function have to be taken into account. TR is functional and is a satellite of left-sided heart disease and/or elevated pulmonary artery pressure most of the time; a particular form is characterized by TR worsening after left-sided valve surgery, which has been shown to impair patient prognosis. A better description of TV anatomy and function by multimodality imaging should help with the appropriate selection of patients who will benefit from either surgical TV repair/replacement or a percutaneous procedure for TR, especially among patients who are to undergo or have undergone primary left-sided valvular surgery.
Nowadays some percutaneous options for tricuspid valve (TV) repair are available: Tricinch (4Tech Cardio, Galway, Ireland) mimicking the Kay procedure, Trialign (Mitralign, Boston, MA, USA) aiming to bicuspidise TV, MitraClip (Abbott Vascular, Abbott Park, Illinois, USA) mimicking Alfieri’s stitch, direct transcatheter annuloplasty with Cardioband (Valtech Cardio, Or Yehuda, Israel) and transcatheter Forma Repair (Edwards Lifesciences, Irvine, California, USA) providing a surface for leaflet coaptation. A multimodality imaging approach is fundamental for defining the pathophysiology of tricuspid regurgitation (TR), preprocedural planning and intraprocedural monitoring. Both 2-dimensional and 3-dimensional (3D) transthoracic echocardiography and transoesophageal echocardiography (TOE) are essential for grading and anatomical characterisation of TR, and evaluation of dimensions and function of right ventricle (RV) and estimation of pulmonary pressure. In particular, 3D echocardiography provides a better anatomical definition of TV apparatus and tricuspid annulus (TA) and additional information about the anatomical relationships of TV and surrounding structures. CT offers complementary information during the preprocedural planning especially for procedures targeting TA such as annular structure and dimensions, quality and amount of annular tissue and its relationship with the right coronary artery, and the sizing of the inferior vena cava. Moreover, appropriate patient selection is crucial. The best candidate seems to be a patient with functional TR due to predominant annular dilatation with modest apical tethering, at least partial preservation of leaflets coaptation, not severe pulmonary hypertension and not advanced RV dilation and dysfunction. An example of intraprocedural multimodality imaging approach with TOE, fluoroscopy, angiography and intracardiac echocardiography is also reported.
- JPMA. The Journal of the Pakistan Medical Association
- Published about 2 months ago
A 75-year-old man underwent implantation of a single chamber implantable cardioverter defibrillator (ICD) for primary prevention of his underlying severe non-ischaemic cardiomyopathy. Thirteen months later, he presented to the emergency room(ER) with inappropriate ICD shocks as a result of over sensing of the right ventricular lead and double counting of the right atrial signals. The chest X-ray (CXR) revealed a right ventricular ICD lead displaced into the right atrium with coiling in the pocket. The right ventricular shocking coil was noted at the tricuspid annulus. The lead was removed from the pocket and was replaced with a new lead. This case represents the classical Twiddler’s syndrome in an ICD with potential lethal consequences.
A 13-year-old girl is reported who died suddenly and unexpectedly in her sleep from previously undiagnosed Ebstein anomaly. At autopsy, there was dilatation of the right atrium with marked dilatation of the right auricle and apical displacement of the tricuspid valve into the right ventricular cavity with atrialization of the upper portion of the right ventricle. There were also prominent dysplastic changes in both the septal and posterior leaflets of the tricuspid valve with thickening of the valve and fusion of leaflets to the wall of the ventricle. Histology of the myocardium showed focal, minor microscopic areas of interstitial fibrosis with marked fibrous dysplasia and thickening of the tricuspid valve. Lethal arrhythmias occur in this condition because of the geographical relationship of the conduction system to the abnormal anatomical structures. As adolescents who died suddenly are often minimally symptomatic, cases will rarely present de novo to forensic autopsy.
A minimally invasive ventricular assist device is under development for percutaneous insertion into the left atrium via transseptal access from the right atrium (RA). This study aimed to mathematically describe the vascular anatomy along possible insertion pathways to determine the device’s maximum outer dimensions. We developed 2-dimensional mathematical models describing the vascular anatomy to the RA from three access points: subclavian vein (SCV), internal jugular vein (IJV), and femoral vein (FV). All pathways terminated by turning from the superior or inferior vena cava (SVC/IVC) into the RA. The model equations were based on restriction points in the pathways and were solved using anatomic size values 1 SD below published mean values so that the device will accommodate most patients. Vessels were considered rigid so that vessel deformation (and therefore risk) is minimized during device insertion. Maximum device length was calculated for a range of device diameters. The length at the most constraining angle in each turn was the maximum allowable device length. The least restrictive pathway was from the right FV, the turn from the IVC through the atrial septum being the most restrictive point. For a 10-mm diameter device, the length restriction for this pathway was 45 mm, whereas those for the right IJV and SCV were 42 and 21 mm, respectively. Medical device developers can apply these models to determine size specifications of new devices, whereas interventional physicians can apply them to determine if an existing device is appropriate for an individual patient.
We herein report a case of atrial tachycardia (AT) originating from the dilated coronary sinus (CS) connected to a persistent left superior vena cava. The earliest activation site of AT was localized at the superior CS ostium, identified using a novel ultra-rapid high-density mapping system (Rhythmia™). Successful ablation was performed at the corresponding position. This report demonstrated the utility of an ultra-rapid high-density mapping system in identifying arrhythmogenic foci in adult cases of congenital heart disease.
We had two cases of neonates with hypoplastic left heart syndrome and intact atrial septum who had unique levoatriocardinal veins. Contrast-enhanced CT and angiography revealed that previously unknown communicating vessels ran from the top of the left atrium and drained into the right atrium. We emphasise that transcatheter atrial septostomy should be performed not through these communicating vessels but using the trans-septal approach in neonates with hypoplastic left heart syndrome and an intact atrial septum.
We report the unique case of a primary cardiac leiomyoma originating from the right ventricle and involving the tricuspid valve in a 43-year-old woman. Echocardiography showed a giant mass causing severe pulmonary stenosis and tricuspid valve regurgitation. The patient underwent surgical excision and histologic examination revealed a primary cardiac leiomyoma. To the best of our knowledge only three cases of primary cardiac leiomyoma have so far been reported, and this is the first case of primary cardiac leiomyoma involving the tricuspid valve apparatus.