Ebstein anomaly is a congenital malformation of the heart that is characterized by apical displacement of the septal and posterior tricuspid valve leaflets, leading to atrialization of the right ventricle with a variable degree of malformation and displacement of the anterior leaflet.
Patients can have a variety of symptoms related to the anatomic abnormalities of Ebstein anomaly and their hemodynamic effects or associated structural and conduction system disease, including the following:
Other less common presenting symptoms include the following:
See Clinical Presentation for more detail.
Physical findings in patients with Ebstein anomaly span a spectrum from subtle to dramatic. They may include the following:
Testing
A 12-lead electrocardiogram may demonstrate the following findings in patients with Ebstein anomaly:
The following imaging studies may be used to assess patients with suspected Ebstein anomaly:
See Workup for more detail.
Treatment of Ebstein anomaly is complex and dictated mainly by the severity of the disease itself and the effect of accompanying congenital structural and electrical abnormalities. Treatment options include medical therapy, radiofrequency ablation, and surgical therapy.
Pharmacotherapy
Ebstein anomaly requires drug treatment for cardiovascular consequences resulting from tricuspid atrialization of the right ventricle, valvular regurgitation, and septal defects. Patients may require antibiotic prophylaxis for bacterial endocarditis.
The following medications are used in patients with Ebstein anomaly:
Nonpharmacotherapy
Radiofrequency ablation of the accessory pathways is an alternative to medication for treatment of arrhythmias. Curative therapy of supraventricular tachycardia with radiofrequency ablation is the treatment of choice. However, in patients without significant structural heart disease, the success rate of this procedure is lower.
Surgical option
Surgical intervention includes the following:
See Treatment and Medication for more detail.
Ebstein anomaly is a congenital malformation of the heart that is characterized by apical displacement of the septal and posterior tricuspid valve leaflets, leading to atrialization of the right ventricle with a variable degree of malformation and displacement of the anterior leaflet.
Wilhelm Ebstein first described a patient with cardiac defects typical of Ebstein anomaly in 1866. In 1927, Alfred Arnstein suggested the name Ebstein's anomaly for these defects. In 1937, Yates and Shapiro described the first case of the anomaly with associated radiographic and electrocardiographic data.
The embryological development of tricuspid valve leaflets and chordae involves undermining of the right ventricular free wall. This process continues to the level of the atrioventricular (AV) junction. In Ebstein anomaly, this process of undermining is incomplete and falls short of reaching the level of the AV junction. In addition, the apical portions of the valve tissue, which normally undergo resorption, fail to resorb completely. This results in distortion and displacement of the tricuspid valve leaflets, and a part of the right ventricle becomes atrialized. In one study involving 50 hearts with the anomaly, the entire right ventricle was found to be morphologically abnormal.[1]
Ebstein anomaly is commonly associated with other congenital, structural, or conduction system disease, including intracardiac shunts, valvular lesions, and accessory conduction pathways (eg, Wolff-Parkinson-White [WPW] syndrome).
The hemodynamic consequences of Ebstein anomaly result from displaced and malformed tricuspid leaflets and atrialization of the right ventricle. The leaflet anomaly leads to tricuspid regurgitation. The severity of regurgitation depends on the extent of leaflet displacement, ranging from mild regurgitation with minimally displaced tricuspid leaflets to severe regurgitation with extreme displacement.
The atrialized portion of the right ventricle, although anatomically part of the right atrium, contracts and relaxes with the right ventricle. This discordant contraction leads to stagnation of blood in the right atrium. During ventricular systole, the atrialized part of the right ventricle contracts with the rest of the right ventricle, which causes a backward flow of blood into the right atrium, accentuating the effects of tricuspid regurgitation.
Ebstein anomaly is a congenital disease of often uncertain cause.
Environmental factors implicated in etiology include the following maternal factors[2] :
The risk of having Ebstein anomaly is higher in white persons than in other races.
Ebstein anomaly probably accounts for 0.5% of cases of congenital heart diseases. Its true prevalence is unknown because mild forms frequently are undiagnosed. With the wide application of echocardiography, more cases are being diagnosed.
Ebstein anomaly is more common in children of white females. However, no specific sex predominance exists.
Ebstein anomaly can present at various stages of life, as follows:
Prognosis depends on the severity of the disease and treatment options available. Pregnancy in women with Ebstein anomaly seems to be well tolerated with adequate supervision.[3, 4]
Poor prognostic signs include the following:
The natural course of the disease varies according to the severity of tricuspid valve displacement. Patients presenting in infancy generally have severe disease and unfavorable prognosis.[7, 8]
The mean age of presentation is in the middle teenage years. According to older observational data, approximately 5% of these patients survive beyond age 50 years. The oldest recorded patient lived to age 85 years.
Complications of Ebstein anomalyinclude the following:
Patients can have a variety of symptoms related to the anatomical abnormalities of Ebstein anomaly and their hemodynamic effects or associated structural and conduction system disease.
Cyanosis is fairly common and frequently due to right-to-left shunt at the atrial level and/or severe heart failure. It is transient in neonatal life, with recurrence in adult life; it may appear for the first time in adult life. The transient appearance/worsening of cyanosis in adult life is due to paroxysmal arrhythmias; once apparent, the cyanosis progressively worsens.
Fatigue and dyspnea are due to poor cardiac output secondary to right ventricular failure and decreased left ventricular ejection fraction.
Palpitations and sudden cardiac death may occur due to paroxysmal supraventricular tachycardia (SVT) or Wolff-Parkinson-White (WPW) syndrome in as many as one third of patients. Fatal ventricular arrhythmias may also occur due to the presence of accessory pathways.
Symptoms of right heart failure include ankle edema and ascites.
Other less common presenting symptoms include the following:
Physical findings, like the symptoms, span a spectrum from subtle to dramatic.
Cyanosis and clubbing may occur. Varying degrees of cyanosis occur at various times in life; there is transient worsening with concurrent arrhythmias.
Precordial asymmetry is usually with left parasternal prominence and, occasionally, right parasternal prominence. An absent left parasternal (ie, right ventricular) lift is an important negative sign.
Jugular venous pulse may be normal owing to a large, thin-walled right atrium, which can absorb the volume and pressure transmitted from the right ventricle through an incompetent tricuspid valve. Large a and v waves appear late in the course of the disease, with development of right heart failure.
Arterial pulses are usually normal. Diminished volume occurs late in the course of the disease due to severe right heart failure and decreased left ventricular stroke volume.
The first heart sound is widely split with a loud tricuspid component secondary to delayed closure of the elongated anterior tricuspid leaflet, which has an increased excursion, often producing a "sail" sound. The mitral component may be soft or absent in the presence of prolonged PR interval. The second heart sound usually is normal but may be widely split when the pulmonary component is delayed due to right bundle-branch block (RBBB).
Additional heart sounds and murmurs may be present, as follows:
Chest radiographs may reveal the following in patients with Ebstein anomaly:
Echocardiogram is the criterion standard for diagnosis.
M-mode echocardiography
Two-dimensional echocardiography
Doppler studies
Assessment of severity and surgical options by echocardiography
Cine MRI is currently not used routinely; it may become a useful noninvasive modality in the future. Right/Left heart volume index correlates well with heart failure markers.[9]
Twelve-lead electrocardiographic (ECG) features of patients with Ebstein anomaly include the following:
Currently, cardiac catherization is rarely performed for the evaluation of Ebstein anomaly. It can confirm echocardiographic findings: Cardiac catherization can reveal right ventricular electrical activity on the intracardiac electrocardiogram (ECG) with simultaneous right atrial pressure and waveform when the catheter is withdrawn from the right ventricle, back across the tricuspid valve into the right atrium.
Of patients with Ebstein anomaly, 25-30% have accessory pathways, and 5-25% have evidence of preexcitation on the surface ECG. Electrophysiologic (EP) studies in patients with tachyarrhythmias can delineate accessory conduction pathways and guide ablative therapy. Right-sided pathways are more common, and 50% of the patients have multiple pathways.
Ebstein anomaly presents with a spectrum of congenital abnormalities of the tricuspid valve and the right ventricle. The age of presentation with symptoms is variable, and a wide range of treatment options is available. Treatment of Ebstein anomaly is complex and dictated mainly by the severity of the disease itself and the effect of accompanying congenital structural and electrical abnormalities. Transfer to a cardiothoracic surgery unit if necessary.
Treatment options include medical therapy, radiofrequency ablation, and surgical therapy.
Administer antibiotic prophylaxis for infective endocarditis
Pharmacotherapy for heart failure includes the use of angiotensin-converting enzyme (ACE) inhibitors, diuretics, and digoxin.
Arrhythmia treatment includes antiarrhythmic drugs or radiofrequency ablation of the accessory pathways. Curative therapy of suptraventricular tachycardia (SVT) with radiofrequency ablation is currently the treatment of choice; however, the success rate is lower than that in patients without significant structural heart disease. Factors associated with lower likelihood of success include the following:
Consult an electrophysiologist and cardiac surgeon for the management of patients with Ebstein anomaly.
A low-sodium diet is recommended for symptomatic relief from fluid overload. Activity may be allowed as tolerated.
Surgical care includes correction of the underlying tricuspid valve and right ventricular abnormalities, correction of any associated intracardiac defects, palliative procedures in early days of life as a bridge to more definitive surgical treatment later, and surgical treatment of associated arrhythmias. Complete repair of Ebstein anomaly in symptomatic neonates has been shown to be feasible, with good early and late survival and excellent functional status.[10] In patients aged 50 years or older with Ebstein anomaly, surgery is associated with good long-term survival and improved functional status, although long-term survival might be improved by performing surgery earlier.[11]
The trend is to perform surgery earlier rather later in the course of heart failure. Indications for surgery are generally as follows:
Various approaches are available to treat structural abnormalities. Tricuspid valve repair is preferred over valve replacement, and bioprosthetic valves are preferred over mechanical prosthetic valves. The atrialized portion of the right ventricle can be resected surgically, and the markedly dilated, thin-walled right atrium can be resected. Associated septal defects may be closed.
In a study of 27 consecutive cone reconstructions to treat severe triscuspid valve (TV) regurgitation associated with Ebstein anomaly, Ibrahim and colleagues retrospectively compared the clinical characteristics, echocardiography, magnetic resonance imaging, and exercise data between preoperative baseline and follow-up. Patients showed improvements in left ventricle filling and objective exercise capacity. The investigators concluded that in patients with severe regurgitation associated with Ebstein anomaly, cone reconstruction of TV offers effective repair.[13]
Da Silva's cone repair is a technique for the surgical reconstruction of the tricuspid valve and the right ventricle in Ebstein anomaly. In one study, investigators evaluated echocardiographic studies and magnetic resonance imaging (MRI) before and after Da Silva’s cone repair for Ebstein anomaly in 20 patients. They found that Da Silva's cone repair created excellent valve function; the size of the right ventricle decreased and the antegrade net stroke volume increased 6 months post-surgery.[14]
Palliative procedures include creation of atrial septal defect, closure of tricuspid valve with plication of the right atrium, and maintenance of pulmonary blood flow through aortopulmonary shunt. Palliative procedures usually are reserved for severely ill infants with otherwise dire prognosis.
Left ventricular dysfunction should not be considered a contraindication to tricuspid valve surgery. In these patients, although early mortality is greater with tricuspid valve surgery, the late results are favorable and left ventricular function seems to improve postoperatively.[3, 15]
Functional status improves after surgery.
Surgical treatments of arrhythmias include the following:
Cardiac transplantation is appropriate in selected patients.
Outpatient follow-up is directed toward the following:
The 2008 American College of Cardiology/American Heart Association (ACC/AHA) 2008 Guidelines for the Management of Adults with Congenital Heart Disease provides detailed information regarding the diagnosis, workup, treatment, follow-up, and instruction regarding nonpregnant, pregnant, and activity level in patients with Ebstein anomaly.[16] Recommendations for the evaluation and management of patients with Ebstein anomaly are summarized below.
It is recommended that all patients with Ebstein anomaly undergo periodic evaluation at a center with expertise in adults with congenital heart disease (CHD).[16]
Class I
Class IIa
Anticoagulation with warfarin is recommended for patients with Ebstein anomaly who have a history of paradoxical embolus or atrial fibrillation. (Class I, level of evidence: C)
Recommendations for catheter interventions for adults with Ebstein anomaly are summarized below.[16]
EPS/pacing issues
Surgical interventions (all class I recommendations)
Surgeons with training and expertise in CHD should perform tricuspid valve repair or replacement with concomitant closure of an atrial septal defect (ASD), when present, for patients with Ebstein anomaly with the following indications (level of evidence: B, for all):
Surgeons with training and expertise in CHD should perform concomitant arrhythmia surgery in patients with Ebstein anomaly and the following indications (level of evidence: B, for all):
Surgical rerepair/replacement of the tricuspid valve is recommended in adults with Ebstein anomaly with the following indications (level of evidence: B, for all):
Other management considerations
Women of reproductive age
Endocarditis prophylaxis
Although patients with Ebstein anomaly may be referred for percutaneous or surgical ASD closure, the presence of Ebstein anomaly may alter the recommendation for intervention.
Use caution in performing percutaneous ablation of an accessory pathway in patients with Ebstein anomaly and an interatrial communication with right-to-left shunt, because of the risk of paradoxical embolus.
The presence of multiple accessory pathways should raise the suspicion for Ebstein anomaly.
Patients with Ebstein anomaly and marked cardiomegaly may complain of few symptoms despite marked limitation. Exercise testing will demonstrate functional limitation and should be included as part of the regular assessment of these patients. Exercise testing should include monitoring of oxygen saturation, because exercise-induced cyanosis may occur.
Newly diagnosed patients with Ebstein anomaly may have been told they have concomitant pulmonary arterial hypertension (PAH), particularly in the presence of cyanosis and right-sided heart enlargement. This is usually a misdiagnosis, because PAH is very rare among Ebstein patients.
Other tricuspid valve disorders may be misdiagnosed as Ebstein anomaly.
Ebstein anomaly requires drug treatment for cardiovascular consequences resulting from tricuspid atrialization of the right ventricle, valvular regurgitation, and septal defects. Patients may require antibiotic prophylaxis for bacterial endocarditis. Treatment of SVT is typically by radiofrequency ablation rather than drug therapy. CHF is treated with ACE inhibitors, diuretics, and digoxin.
Clinical Context: Increases excretion of water by interfering with chloride-binding cotransport system, which in turn inhibits sodium and chloride reabsorption in ascending loop of Henle and distal renal tubule. Dose must be individualized. Depending on response, administer at increments of 20-40 mg no sooner than 6-8 h after previous dose until desired diuresis occurs. When treating infants, titrate with 1 mg/kg/dose increments until satisfactory effect achieved.
These agents promote excretion of water and electrolytes by the kidneys. They are used in treatment of hypertension, heart failure, and hepatic, renal, or pulmonary disease when salt and water retention has resulted in edema or ascites.
Clinical Context: Cardiac glycoside with direct inotropic effects in addition to indirect effects on cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions. Its indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.
These agents possess positive inotropic activity, which is mediated by inhibition of sodium-potassium adenosine triphosphatase (Na+/K+ ATPase). Also, cardiac glycosides reduce conductivity in the heart, particularly through the atrioventricular node, and therefore have a negative chronotropic effect. The cardiac glycosides have very similar pharmacological effects but differ considerably in their speed of onset and duration of action. They are used to slow the heart rate in supraventricular arrhythmias, especially atrial fibrillation, and also are administered in chronic heart failure.
Clinical Context: Competitive inhibitor of ACE. Reduces angiotensin II levels, decreasing aldosterone secretion.
ACE inhibitors are beneficial in all stages of chronic heart failure. Dyspnea and exercise tolerance are improved. Unlike diuretics, studies demonstrate improvement of survival and reduced progression of mild or moderate heart failure to more severe stages. They have benefit in asymptomatic left ventricular dysfunction.