The absence of pulmonary artery closure on palpation is the clinical manifestation of Ebstein syndrome. Ebstein syndrome, also known as Ebstein malformation, is a condition in which the tricuspid septal and/or posterior valves occasionally attach to the right ventricular wall proximal to the apex along with the anterior valve inferiorly accounting for approximately 0.5% to 1.0% of precordial disease. This is a rare disease, first reported by Ebstein in 1866. This disease is also known as tricuspid inferior valve malformation. Occasionally, there is a family history, and offspring of mothers taking lithium early in pregnancy are susceptible to this disease. In the functional right ventricle, systolic pressure may be normal, while diastolic pressure is often increased, similar to constrictive pericarditis. Both systolic and diastolic pressures are elevated in the atrial chambers. There may be a systolic pressure difference on both sides of the pulmonary valve and a diastolic pressure difference on both sides of the tricuspid valve. The former may be due to an overgrown tricuspid leaflet that partially obstructs the right ventricular outflow tract; the latter is due to a tricuspid valve malformation with narrowing of the tricuspid orifice. The main pathologic and anatomic features of the absence of pulmonary closure on palpation are the atrialization of the right ventricle with an inferiorly displaced tricuspid valve malformation and functional right ventricular cavity reduction. The right atrioventricular ring is normally positioned (often enlarged) and the anterolateral tricuspid valve is often normally attached to the annulus fibrosus, whereas the attachment points of the diaphragmatic and posterior valves are significantly inferior to the endocardium of the right ventricular wall The degree of inferiority and the mode of attachment varies from person to person, even though the attachment points of the affected valves are adjacent to the annulus fibrosus, they can often adhere to the right ventricular wall at various sites distal to the annulus fibrosus because of the excessive leaflet length. In addition, these leaflets may be attached to the ventricular septum and right ventricular apex by means of malformed tendons, and the posterior tricuspid valve is often underdeveloped or completely absent. In a small number of patients, the tricuspid valve fuses into a diaphragm in the ventricular cavity, with an orifice in the middle or lateral edge through which right atrial blood flow must be injected into the ventricle, thus impeding the emptying of the atrium. As the tricuspid valve moves downward, the right atrium takes over part of the right ventricle, and the wall of the ventricle in this area is thinned and atrialized, resulting in a significant enlargement of the right atrial cavity. The atrialized right ventricle is functionally part of the right atrium, but retains the characteristics of the right ventricular muscle in terms of electrical activity. The larger the atrialized right ventricular portion, the smaller the functional right ventricular cavity. The atrialized right ventricle cannot participate in right ventricular emptying; instead, it acts as a ventricular wall tumor that paradoxically dilates when the ventricle contracts, thus interfering with right ventricular ejection. In Ebstein syndrome, there is often an interventricular traffic (seen in 80% of cases), which can be either an unclosed foramen ovale or an atrial septal defect. In a few cases, other congenital anomalies may also be combined, such as aortic constriction, ventricular septal defect pulmonary valve stenosis or atresia, patent ductus arteriosus or corrected transposition of the great vessels. In the latter case, the anatomically right ventricle, which is functionally the left ventricle of the body circulation, may clinically present with mitral valve closure insufficiency, and is thus referred to as a left-sided Ebstein malformation. The pathophysiological alterations of this malformation depend on the presence or absence of functional right ventricular volume of pulmonary stenosis and the degree of tricuspid regurgitation. If there is a coexisting pulmonary stenosis with a significantly reduced functional right ventricular cavity and severe tricuspid regurgitation, then the volume of blood expelled during right ventricular systole is inevitably reduced and the clinical picture will be one of early onset symptoms and poor prognosis. Conversely, if the hemodynamic changes are mild, the clinical picture will be one of late onset and mild symptoms with a better prognosis. As mentioned previously, this malformation is often associated with the presence of interventricular traffic. If the tricuspid valve lesion is mild and an atrial septal defect is present, then a left-to-right shunt may occur at the atrial level; or, because the tricuspid valve lesion is mild and the foramen ovale is closed, there will be no shunt. In the third case, a right-to-left shunt at the atrial level may occur because of a severe tricuspid valve malformation and elevated right atrial pressure. In the first two cases, there is often no clinical cyanosis; in the third case, there is cyanosis. In a few patients, even without a significant right-to-left shunt, there may be mild clinical cyanosis due to low cardiac output and increased arteriovenous oxygen difference. In addition, in the functional right ventricle, systolic pressure may be normal, while diastolic pressure is often increased, similar to constrictive pericarditis. Both systolic and diastolic pressures are elevated in the atrial chambers. There may be a systolic pressure difference on both sides of the pulmonary valve and a diastolic pressure difference on both sides of the tricuspid valve. The former may be due to an overgrown tricuspid leaflet that partially obstructs the right ventricular outflow tract; the latter is due to a tricuspid valve malformation with narrowing of the tricuspid orifice.