INTRODUCTION — Ebstein anomaly is a congenital malformation that is characterized primarily by abnormalities of the tricuspid valve and right ventricle (figure 1). The clinical presentation of Ebstein anomaly varies widely, ranging from the critically ill fetus to the asymptomatic adult, depending upon the degree of anatomic abnormality. The clinical manifestations and diagnosis of Ebstein anomaly are discussed here.
The management and prognosis of Ebstein anomaly are discussed separately. (See "Ebstein anomaly: Management and prognosis".)
EPIDEMIOLOGY — The incidence of Ebstein anomaly in the general population has been estimated to be 1.2 to 5 in 100,000 live births with no predilection for either gender [1-4]. The genetic predisposition for Ebstein anomaly is considered heterogeneous [5-8]. The risk of Ebstein anomaly in infants of mothers taking lithium during early pregnancy is discussed separately. (See "Teratogenicity, pregnancy complications, and postnatal risks of antipsychotics, benzodiazepines, lithium, and electroconvulsive therapy", section on 'Lithium'.)
Tricuspid valve — The morphology of the tricuspid valve in Ebstein anomaly, and consequently the clinical presentation, is highly variable. The tricuspid valve leaflets demonstrate variable degrees of failed delamination (separation of the valve tissue from the myocardium) with fibrous and muscular attachments to the right ventricular myocardium (image 1).
●The displacement of hinge points of septal and posterior (inferior) leaflets into the right ventricle toward the apex and right ventricular outflow tract is the hallmark finding of Ebstein anomaly.
●The posterior (inferior) and septal tricuspid valve leaflets are generally most severely affected, related to the failure of delamination from the myocardium. The tricuspid valve functional orifice is generally displaced anteriorly and downward from the atrioventricular junction toward the right ventricular apex, and sometimes superiorly toward the right ventricular outflow tract along the direction of blood flow (rotation of the tricuspid functional orifice along the inner curvature of the right ventricle).
●The anterior leaflet is the largest leaflet and is usually attached to the anatomic tricuspid valve annulus at the atrioventricular junction, with variable tethering to the right ventricular endocardium; this leaflet is often referred to as being "sail-like."
The free edges of the leaflets of the tricuspid valve may attach to chordae or directly to the papillary muscle(s) or the underlying myocardium.
In Ebstein anomaly, the tricuspid valve typically shows variable degrees of regurgitation; a severe degree of regurgitation is common. Tissue defects within the leaflets of the tricuspid valve ("fenestrations") may contribute to the regurgitation. Tricuspid valve stenosis is rare in Ebstein anomaly.
Right ventricle — The displacement of the valve divides the right ventricle into two chambers:
●The proximal portion is called "atrialized right ventricle" because of a downward displacement of the tricuspid valve and functional orifice.
●The distal chamber, the functional right ventricle, is of variable size . This portion of the right ventricle may appear small on the echocardiographic apical four-chamber view but often still appears enlarged by cardiovascular magnetic resonance (CMR) imaging . In some severe cases, the functional right ventricle consists of only the right ventricular outflow tract and may not be visible from the apical four-chamber view on echocardiography.
Due to the underlying myocardial abnormalities, right ventricular performance is almost always abnormal. The atrialized right ventricle is usually thin-walled and demonstrates poor contractility. Furthermore, right ventricular ejection fraction may overestimate true right ventricular contractility in the setting of severe tricuspid regurgitation.
Associated cardiovascular defects — Ebstein anomaly is commonly associated with one or more congenital cardiac malformations in addition to the tricuspid valve and right ventricular findings.
The following findings are the most common [10-13]:
●Patent foramen ovale (PFO) or atrial septal defect (ASD); most commonly secundum ASD. Interatrial communication is commonly identified in patients with Ebstein anomaly. Patients with PFO or ASD can develop cyanosis from right to left shunting, particularly with exercise, and are at risk of paradoxical embolism. (See "Patent foramen ovale" and "Clinical manifestations and diagnosis of atrial septal defects in adults".)
In one series, 79 percent of patients had either a persistent or previously closed PFO or atrial septal defect . In contrast, in a registry study including 530 patients with Ebstein anomaly from Denmark and Sweden, concomitant atrial septal defect only was identified in 10.7 percent, and other congenital cardiac disease was identified in 42.5 percent .
●Ventricular septal defect. (See "Isolated ventricular septal defects (VSDs) in infants and children: Anatomy, clinical features, and diagnosis".)
●Pulmonary outflow tract obstruction is rare and may be due to anatomic or functional pulmonary atresia, structural pulmonic valve stenosis, or occasionally the displaced tricuspid valve. (See "Clinical manifestations and diagnosis of pulmonic stenosis in adults".)
●Patent ductus arteriosus. (See "Clinical manifestations and diagnosis of patent ductus arteriosus (PDA) in term infants, children, and adults".)
●Accessory conduction pathway(s) are present in 6 to 36 percent of patients with Ebstein anomaly , predisposing patients to arrhythmias. Syncope and sudden death have been reported and may be caused by atrial fibrillation with a rapid ventricular response due to fast conduction through an accessory pathway or from ventricular arrhythmias. Arrhythmias may also occasionally precipitate heart failure. (See "Wolff-Parkinson-White syndrome: Anatomy, epidemiology, clinical manifestations, and diagnosis", section on 'Associated cardiac abnormalities'.)
●Left heart lesions are occasionally identified in Ebstein anomaly, including left ventricular systolic and diastolic dysfunction, mitral valve prolapse, bicuspid aortic valve, myocardial changes resembling left ventricular noncompaction, and, rarely, left ventricular outflow tract obstruction . The left ventricle may be small in patients with Ebstein anomaly due to severe tricuspid valve regurgitation, or it may appear small by imaging due to marked right heart involvement.
Clinical presentation — The clinical presentation of Ebstein anomaly varies widely depending upon the extent of tricuspid valve disease, the severity of right ventricular dysfunction, the direction of the shunt across the atrial septum, and any associated congenital cardiac lesions.
The age of diagnosis of Ebstein anomaly has markedly declined since the 1970s, as illustrated by the above cited registry study in which the median age of diagnosis declined from 26.9 years during 1970 to 1979 to 4.8 months during 2000 to 2017, likely reflecting improved diagnostic modalities .
In general, symptoms are related to the degree of anatomic abnormality (ie, the degree of displacement and the functional status of the tricuspid valve leaflets, presence of inter-atrial communication, and severity of right ventricular dilation and dysfunction). The wide spectrum of disease is illustrated by the following clinical presentations:
●The anomaly may be fatal in utero or shortly after birth if severe cardiomegaly, pulmonary hypoplasia due to massive cardiomegaly, and heart failure are present .
●Children and adults with marked tricuspid leaflet displacement may have severe regurgitation, right-sided heart failure, elevated right atrial pressures, and significant cyanosis due to right-to-left interatrial shunting with or without functional/anatomic pulmonary valve atresia.
●In contrast, patients with milder apical displacement and milder dysfunction of the tricuspid valve (mild to moderate tricuspid regurgitation) may remain asymptomatic through adulthood or present in adulthood with arrhythmia or paradoxical embolic event .
In a review of 220 patients with Ebstein anomaly presenting between 1958 and 1991, early age at presentation was frequently associated with other cardiac lesions, particularly atrial septal defect and pulmonary stenosis, which predisposes to cyanosis from right-to-left shunting . The clinical presentation varied with age at diagnosis:
●Fetuses – An abnormal routine prenatal scan (86 percent)
●Neonates – Cyanosis (74 percent)
●Infants – Heart failure (43 percent)
●Children – Murmur (63 percent)
●Adolescents and adults – Arrhythmia (42 percent)
Symptomatic neonates with severe cyanosis, severe cardiomegaly, and respiratory distress require intense medical management. Circular shunt and fetal hydrops are markers of the worst prognosis, as there are limited surgical options. A circular shunt can develop in utero, or after birth if pulmonary valve regurgitation and patent ductus arteriosus are present; this is a result of blood flowing from left ventricle to aorta to pulmonary artery (through ductus arteriosus) and then retrograde through the pulmonary valve, right ventricle, and tricuspid valve, across the atrial septum and back into the left ventricle and aorta. This circular shunt adds significant volume load to the ventricles in the presence of hypoxemia, leading to severe congestive heart failure in neonates and hydrops in fetuses with Ebstein anomaly.
In infants with severe tricuspid regurgitation, dyspnea, heart failure, and cyanosis from shunting across an atrial septal defect may be present soon after birth, because of high pulmonary vascular resistance . These symptoms and signs often improve as pulmonary vascular resistance decreases. However, in cases with mechanical obstruction to right ventricular outflow related to pulmonary atresia, small pulmonary arteries, pulmonary valve stenosis, or a noncompliant small right ventricle, improvement may not occur or be limited.
In children, adolescents, and adults, symptoms such as exertional dyspnea, fatigue, cyanosis, transient ischemic attack/stroke, and palpitations may occur; these symptoms may be due to right ventricular dysfunction, severe tricuspid valve regurgitation, or right-to-left shunt at the atrial level. Atrial tachyarrhythmias are present in approximately 20 to 30 percent of cases across age groups, with greater frequency in adolescents and adults [15,17]. Some of these arrhythmias may be due to accessory conduction pathway(s), present in up to 20 percent of patients; the majority of these pathways are located around the orifice of the malformed tricuspid valve [11,18,19]. Patients with Ebstein anomaly who have an interatrial communication are at risk for paradoxical embolization and may develop symptoms of cyanosis, stroke, transient ischemic attack, or brain abscess . (See "Wolff-Parkinson-White syndrome: Anatomy, epidemiology, clinical manifestations, and diagnosis".)
Physical examination — Physical findings vary with the severity of pathology and the magnitude of right-to-left interatrial shunting . The following observations apply to patients with more severe disease (usually neonates and children); those with less severe disease usually present with a murmur and click commonly mistaken for mitral valve prolapse.
Cyanosis may be severe in infants. Common findings in older children include mild cyanosis, prominent "a" wave in the distended jugular veins, and hepatomegaly. The last finding represents passive hepatic congestion resulting from tricuspid regurgitation and elevated right atrial pressure. There may also be a palpable prominent diffuse parasternal impulse and occasionally a systolic thrill is noted at the left lower sternal border. (See "Examination of the jugular venous pulse" and "Examination of the precordial pulsation".)
On auscultation, first and second heart sounds are widely split due to the right bundle branch block; an early systolic click or "sail sound" may also be heard . A prominent S3 and/or a loud S4 give the impression of multiple heart sounds (triple or quadruple gallop). A systolic murmur from tricuspid regurgitation is a common finding; this murmur characteristically increases in intensity with inspiration and may be associated with a mid-diastolic murmur due to the high diastolic flow volume across the tricuspid annulus. (See "Auscultation of cardiac murmurs in adults".)
However, the murmur may be very soft or absent in adults because the low velocity of the to-and-fro flow and rapid equalization of pressure across the tricuspid valve do not result in blood flow turbulence. When tricuspid regurgitation is severe, jugular venous distension and a prominent "v" wave is occasionally seen; the "v" wave is often absent in Ebstein anomaly due to a large and compliant right atrium and atrialized right ventricle that absorbs the tricuspid regurgitation. For the same reason, the liver may not be pulsatile even in the setting of severe tricuspid valve regurgitation.
Initial test results — An electrocardiogram (ECG) and a chest radiograph are common tests obtained in the initial evaluation of cardiac patients. Further testing for diagnosis and evaluation of Ebstein anomaly (including echocardiography which is a key test) is discussed below. (See 'Approach to diagnosis and evaluation' below.)
Electrocardiogram — An ECG is not required for the diagnosis of Ebstein anomaly but is an important component of the overall evaluation of patients with this condition to detect arrhythmias and evidence of preexcitation . The ECG usually reveals abnormal findings in Ebstein anomaly. These include (waveform 1B) [14,23]:
●Right atrial enlargement with characteristic "Himalayan P waves" and right bundle branch block.
●Preexcitation with a left bundle branch pattern with predominant S waves in the right precordium due to right-sided accessory pathway (waveform 1A-B).
●Preexcitation can sometimes be subtle. Right ventricular preexcitation may manifest as a lack of right bundle branch block with a short PR interval.
●Low-voltage QRS over the right-sided chest leads.
●Supraventricular tachycardia may be present with or without preexcitation; other forms of atrial tachycardia, such as ectopic atrial tachycardia, atrial flutter, or atrial fibrillation, may be seen in older persons.
●PR interval prolongation may also be seen; this is primarily due to intra-atrial conduction delay rather than atrioventricular nodal dysfunction.
Chest radiograph — A chest radiograph is not required for the diagnosis of Ebstein anomaly but is a common component of the evaluation . The chest radiograph results vary depending upon the severity of the disease . In severe cases, the chest radiograph reveals massive cardiomegaly (often termed a "wall-to-wall" heart) with a small ascending aorta and normal or diminished pulmonary vascularity (image 2). The right atrium is prominent and makes up the right heart border; the left heart border becomes straight or convex due to dilated and displaced right ventricular outflow. The chest radiograph may be normal in patients with mild disease.
DIAGNOSIS AND EVALUATION
When to suspect Ebstein anomaly — Ebstein anomaly should be suspected in cyanotic infants, children, and adults, and in individuals with tricuspid regurgitation with or without heart failure and in those presenting with paradoxical systemic embolism or arrhythmias. Ebstein anomaly also may be detected as an incidental finding on an echocardiogram performed for unrelated reasons, including in asymptomatic individuals.
How to diagnose Ebstein anomaly — The diagnosis of Ebstein anomaly may be suspected clinically, but is confirmed by identification of apical displacement of the attachment of the septal tricuspid valve leaflet by ≥8 mm/m2 indexed by body surface area compared with the attachment of the anterior mitral valve leaflet. This is most commonly demonstrated in the apical four-chamber transthoracic echocardiographic view (figure 1 and image 1 and movie 1). This finding may also be appreciated by other imaging techniques, such as CMR.
Other features commonly associated with Ebstein anomaly are described below. (See 'Key features' below.)
Approach to diagnosis and evaluation — We recommend the following approach for diagnosis and evaluation of Ebstein anomaly. Further details of individual tests are discussed below.
•We recommend CMR imaging for patients with nondiagnostic echocardiography as well as in patients undergoing surgical tricuspid valve intervention. CMR provides information complementary to that obtained from echocardiography, including quantification of right ventricular size and function in addition to visualization of tricuspid valve anatomy and additional structural abnormalities [25-28]. (See 'Cardiovascular magnetic resonance' below.)
●Additional tests to evaluate patients with Ebstein anomaly:
•We recommend routine formal exercise testing with oximetry to assess exercise capacity, heart rate and blood pressure response to exercise, potential desaturation with exercise, and exercise-induced arrhythmias. Cardiopulmonary exercise testing with measurement of oxygen consumption is helpful in assessing functional limitation (eg, when cardiomegaly is present with few or no symptoms). (See 'Exercise testing' below and "Cardiopulmonary exercise testing in cardiovascular disease".)
•We suggest the following routine arrhythmia assessment in patients with Ebstein anomaly: an ECG, ECG monitoring during exercise, and annual 24-hour continuous ambulatory ECG (Holter) monitoring or use of another prolonged heart rhythm monitoring device. For patients with tachyarrhythmias, evidence of pre-excitation on ECG, or planned operation for Ebstein anomaly, we suggest a consultation with a congenital heart rhythm specialist for further evaluation, which may include an electrophysiologic study (EPS). (See 'Arrhythmia evaluation' below.)
•Cardiac catheterization with hemodynamic assessment is recommended for patients with suspected pulmonary artery hypertension or discordant clinical and noninvasive testing, and for patients who are being evaluated for possible patent foramen ovale (PFO) or atrial septal defect (ASD) device closure or bidirectional cavopulmonary anastomosis. (See 'Cardiac catheterization' below.)
Key imaging tests
Key features — Comprehensive transthoracic two-dimensional and Doppler echocardiography is the most useful tool for establishing a diagnosis of Ebstein anomaly (movie 1 and image 1) [25,26]. The transthoracic echocardiogram generally confirms the diagnosis, determines the severity of the disease, and defines potential associated cardiac defects. The four-chamber view is particularly helpful, as it demonstrates the degree of mobility of the anterior leaflet, the displacement of the septal leaflet, and an impression of the severity of the tricuspid regurgitation. All echocardiographic views are important to delineate the severity of the tricuspid valve regurgitation, which may be incompletely visualized using the standard four-chamber view. Three-dimensional echocardiography is being used with increasing frequency to supplement standard two-dimensional images for analysis of tricuspid valve anatomy and for assessment of right ventricular size and function . (See "Echocardiographic evaluation of the tricuspid valve".)
The following are the most important echocardiographic findings [29,30]:
●The key diagnostic finding for Ebstein anomaly is the apical displacement of the septal tricuspid valve leaflet indexed to the body surface area (by ≥8 mm/m2 [compared with the position of the anterior mitral valve leaflet]) demonstrated in the apical four-chamber view. The degree of displacement affects the severity of clinical manifestations.
●Abnormalities of the tricuspid valve and right heart of varying severity are seen among patients with Ebstein anomaly:
•Degree of failure of delamination of each of the three leaflets. (See 'Tricuspid valve' above.)
•Tricuspid regurgitation – This is usually low velocity (since pulmonary pressures are normal) with an origin at the most apically or anteriorly displaced point of the valve. The jet may be missed due to its laminar nature or due to unusual direction, such as inferiorly in a valve that is displaced into the right ventricular outflow tract. Occasionally, tricuspid regurgitation can be best assessed in parasternal right ventricular inflow views and modified parasternal short-axis views.
Formal quantification of tricuspid valve regurgitation is challenging in patients with Ebstein anomaly. In non-Ebstein adults, the criteria for severe tricuspid regurgitation include a vena contracta width >0.7 cm and systolic flow reversal in the hepatic veins [31,32]. However, these features are often not present in Ebstein anomaly patients of any age due to the large compliant right atrium and atrialized right ventricle . A significant leaflet coaptation gap on 2D echo associated with a large regurgitant jet on color Doppler is the best indicator of severe regurgitation in Ebstein anomaly [25,26]. (See "Etiology, clinical features, and evaluation of tricuspid regurgitation", section on 'Echocardiography'.)
•An increase in right heart volume, caused by an enlarged atrialized portion of the right ventricle and volume overload of the functional right ventricle. (See 'Right ventricle' above.)
●Concurrent congenital lesions are commonly seen (see 'Associated cardiovascular defects' above):
•ASD or PFO, often with associated bidirectional shunting. In patients with suboptimal echocardiographic image quality, saline-contrast echocardiography provides a sensitive test to detect right-to-left intracardiac shunting.
•Left-sided cardiac lesions (left ventricular systolic and diastolic dysfunction, mitral valve prolapse, bicuspid aortic valve, small left ventricle).
•L-transposition of the great arteries. (See "L-transposition of the great arteries (L-TGA): Anatomy, clinical features, and diagnosis".)
A transesophageal echocardiogram may provide additional information when the transthoracic echocardiographic images are not technically sufficient to identify the structural and functional abnormalities .
Intrauterine diagnosis of Ebstein anomaly can be made by fetal echocardiography .
GOSE score (Celermajer index) — The Great Ormond Street Score (GOSE) is commonly used for echocardiographic evaluation of the neonate. This score is defined as the ratio of the area of the right atrium and atrialized right ventricle to the combined area of the functional right ventricle, left atrium, and left ventricle; the greater the ratio, the worse the prognosis [35-37].
Cardiovascular magnetic resonance — Since information obtained from CMR is complementary to that obtained from echocardiography, combined CMR and echocardiographic imaging are usually performed prior to and following surgical tricuspid valve intervention [25-28]. We generally suggest pre- and postoperative CMR for all patients with Ebstein anomaly who do not require general anesthesia for the scan and for selected patients who do require general anesthesia for scanning . CMR imaging primarily enables quantification of right ventricular size and function. Visualization of tricuspid valve anatomy is also possible (image 3) [38-40]. Given the unusual tricuspid valve and right ventricular morphology and lack of standardized CMR imaging protocols, variability of calculated right ventricular volumes may be noted when Ebstein patients are compared with patients with other congenital heart defects; in addition, there may be variability of volumetric measurements between different centers [25,26,28,41]. Furthermore, the right ventricular ejection fraction may overestimate true right ventricular contractility in the setting of severe tricuspid regurgitation. Prediction of right ventricular function after tricuspid valve repair or replacement remains difficult. Right ventricular function is generally depressed immediately after tricuspid valve repair or replacement and may or may not recover over time with right ventricular remodeling.
Additional tests — The following additional tests are generally performed to evaluate patients diagnosed with Ebstein anomaly.
Exercise testing — For patients with Ebstein anomaly, we perform formal exercise testing with oximetry or cardiopulmonary exercise testing to assess exercise capacity, heart rate and blood pressure response to exercise, potential desaturation with exercise, and exercise-induced arrhythmias. Pulse oximetry at rest and during exercise in patients with Ebstein anomaly aids in risk stratification . The resting oxygen saturation is a major predictor of exercise tolerance and oxygen saturation at peak exercise .
For patients with Ebstein anomaly who have cardiomegaly with few or no symptoms, cardiopulmonary exercise testing with measurement of oxygen consumption is helpful in assessing functional limitations. (See "Cardiopulmonary exercise testing in cardiovascular disease".)
Arrhythmia evaluation — For arrhythmia assessment, we suggest an ECG and annual continuous 24-hour ambulatory ECG (Holter) monitoring or monitoring with another prolonged ambulatory monitoring device, as well as ECG monitoring during exercise. For patients with tachyarrhythmias, evidence of pre-excitation on ECG, or planned operation for Ebstein anomaly, consultation with a congenital heart rhythm specialist is suggested. As noted above, the ECG may reveal evidence of arrhythmias or preexcitation. We generally suggest annual 24-hour ambulatory (Holter) monitoring or monitoring with another prolonged ambulatory monitoring device as a means of identifying arrhythmias.
Among patients referred to a congenital heart rhythm specialist, further evaluation may include EPS. The role of EPS for the identification of accessory pathways and radiofrequency catheter ablation is discussed separately. EPS may also help exclude the presence of ventricular arrhythmias. In our practice, we perform EPS in many adult Ebstein patients prior to operation to detect concealed pathways, guide the extent of intraoperative Maze or cryoablation procedures, and determine the risk of ventricular arrhythmias. In children, preoperative EPS is generally limited to those with Wolff-Parkinson-White syndrome or known/suspected arrhythmia . (See "Wolff-Parkinson-White syndrome: Anatomy, epidemiology, clinical manifestations, and diagnosis", section on 'Evaluation'.)
Cardiac catheterization — Cardiac catheterization with hemodynamic assessment is recommended for patients with suspected pulmonary artery hypertension, discordant clinical and noninvasive testing, and for patients who are being evaluated for possible PFO or ASD device closure or bidirectional cavopulmonary anastomosis. Information concerning pulmonary artery pressures and left ventricular end-diastolic pressure is particularly important if a bidirectional cavopulmonary shunt is being considered . Cardiac catheterization with hemodynamic assessment is also recommended for patients with advanced features of Ebstein anomaly and biventricular dysfunction to help guide the choice between conventional surgical intervention or cardiac transplantation.
Comprehensive hemodynamic cardiac catheterization is required prior to potential device closure, as PFO or ASD closure may further increase right atrial filling pressures at rest or during exercise and can lead to hemodynamic decompensation. In selected cases, assessment of cardiac hemodynamics during exercise with and without balloon-occlusion of the interatrial septal defect may be helpful for decision making. Since isolated ASD catheter-based or surgical closure may result in hemodynamic decompensation, surgical repair of Ebstein anomaly combined with ASD closure is generally preferred over isolated device ASD closure. (See "Ebstein anomaly: Management and prognosis".)
Coronary angiography or coronary computed tomographic angiography is suggested when surgical repair is planned in patients with suspected coronary artery disease or risk factors for coronary disease, including men ≥35 years old, premenopausal women ≥35 years with coronary risk factors, and postmenopausal women .
DIFFERENTIAL DIAGNOSIS — Ebstein anomaly should be distinguished (generally by echocardiography and other clinical features) from other causes of tricuspid regurgitation and right-sided chamber enlargement including the following conditions. A key distinction is that other conditions are associated with a septal leaflet displacement index of less than 8 mm/m2 body surface area. (See "Etiology, clinical features, and evaluation of tricuspid regurgitation" and "Arrhythmogenic right ventricular cardiomyopathy: Anatomy, histology, and clinical manifestations".)
●Uhl anomaly, which is characterized by right ventricular dilation with thin, hypokinetic right ventricular myocardium. (See "Arrhythmogenic right ventricular cardiomyopathy: Anatomy, histology, and clinical manifestations", section on 'Uhl anomaly'.)
●Congenital tricuspid valve dysplasia, which is characterized by malformed valve leaflets with no excessive displacement or tethering of tricuspid valve leaflets to the right ventricular myocardium.
●Tricuspid valve prolapse, which is manifest as tricuspid valve leaflet prolapse without excessive displacement or tethering of the leaflets to the right ventricular myocardium.
●Tricuspid valve vegetations due to infectious or noninfectious endocarditis, which is characterized by the presence of vegetations with no tethering or displacement of tricuspid valve leaflets into the right ventricular myocardium.
●Carcinoid heart disease in which valve leaflets are thickened and retracted resulting in tricuspid valve regurgitation. (See "Carcinoid heart disease", section on 'Diagnosis and evaluation'.)
●Traumatic injury of the tricuspid valve or ruptured tricuspid valve chordae, which is suggested by a history of cardiac instrumentation (eg, right ventricular endomyocardial biopsy, electrophysiologic study) or chest trauma and features of one or more flail leaflets.
●Arrhythmogenic right ventricular cardiomyopathy with a morphologically normal tricuspid valve with annular dilation, right ventricular dilation, and dysfunction. (See "Arrhythmogenic right ventricular cardiomyopathy: Anatomy, histology, and clinical manifestations".)
●Idiopathic enlargement of the right atrium, a rare disorder that may be associated with tricuspid regurgitation .
●Functional tricuspid regurgitation caused by annular dilatation or impaired right ventricular geometry of various causes.
Ebstein anomaly should also be distinguished from other causes of cyanosis, which are usually also diagnosed by echocardiography. In Ebstein anomaly, the right heart is frequently enlarged but pulmonary artery hypertension is less common, in contrast to cyanotic congenital heart disease associated with Eisenmenger syndrome. The evaluation of cyanosis in infants and children is discussed separately. (See "Medical management of cyanotic congenital heart disease in adults" and "Approach to cyanosis in the newborn" and "Approach to cyanosis in children".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Arrhythmias in adults" and "Society guideline links: Cardiac valve disease" and "Society guideline links: Congenital heart disease in adults".)
SUMMARY AND RECOMMENDATIONS
●Ebstein anomaly is a congenital malformation characterized by variably malformed and displaced tricuspid valve leaflets that are partly attached to the tricuspid valve annulus and partly attached to the right ventricular endocardium. These features cause tricuspid valve regurgitation and right heart enlargement. (See 'Morphology' above.)
●Cardiac defects associated with Ebstein anomaly include atrial septal defect/patent foramen ovale, one or more accessory conduction pathways, ventricular septal defect, pulmonary outflow obstruction, patent ductus arteriosus, mitral valve prolapse, bicuspid aortic valve, and left ventricular noncompaction. (See 'Associated cardiovascular defects' above.)
●The clinical presentation varies with the severity of the lesion. Severe malformations are associated with fetal hydrops, cyanosis in neonates, and heart failure in infants. Milder disease may be detected as an incidental murmur in children or adults; these patients may remain asymptomatic for decades. Adolescents and adults commonly present with atrial arrhythmias, often associated with one or more accessory pathways. (See 'Clinical manifestations' above and "Ebstein anomaly: Management and prognosis", section on 'Prognosis'.)
●The diagnosis of Ebstein anomaly is made by identification of apical displacement of the attachment of the septal tricuspid valve leaflet indexed by body surface area by ≥8 mm/m2 compared with the attachment of the anterior mitral valve leaflet, demonstrated in the apical four-chamber transthoracic echocardiographic view (figure 1 and image 1) This finding may also be appreciated by other imaging techniques. (See 'How to diagnose Ebstein anomaly' above.)
●Echocardiography is generally the key test for diagnosis and initial anatomic evaluation of Ebstein anomaly. We recommend cardiovascular magnetic resonance (CMR) imaging for patients with nondiagnostic echocardiography, as well as in patients undergoing surgical tricuspid valve intervention. CMR provides information complementary to that obtained from echocardiography, including quantification of right ventricular size and function. (See 'Approach to diagnosis and evaluation' above.)
●Diagnostic features of Ebstein anomaly include apical displacement of the septal tricuspid leaflet compared with the position of the anterior mitral valve leaflet (by ≥8 mm/m2 body surface area), multiple fibrous attachments of tricuspid valve leaflets to the underlying RV myocardium, enlarged right heart volume, and low velocity tricuspid regurgitation. (See 'Key features' above.)
●Evaluation of the patient with Ebstein anomaly includes exercise testing with oximetry, as well as arrhythmia evaluation, which in some cases includes electrophysiologic study. Additional testing such as cardiopulmonary exercise testing, cardiac catheterization, and coronary angiography are indicated in only selected patients. (See 'Diagnosis and evaluation' above.)
●The differential diagnosis of Ebstein anomaly includes other causes of tricuspid regurgitation or right-sided chamber enlargement and other causes of cyanosis. A key distinction is that other conditions are associated with a septal leaflet displacement index of less than 8 mm/m2 body surface area. (See 'Differential diagnosis' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff thank Brojendra N Agarwala, MD, and Ziyad M Hijazi, MD, MPH, FAAP, FACC, MSCAI, FAHA, who contributed to earlier versions of this topic review.
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