Category	Details
Definition	A rare congenital heart disease characterized by complete or partial absence of the right ventricular (RV) myocardium, resulting in a thin, noncontractile RV wall (“parchment heart”).
Cause	Believed to result from abnormal embryologic development or apoptosis (cell death) of RV myocardium during fetal life. Exact genetic cause is unclear.
Structural Changes	The RV free wall lacks myocardium but retains its endocardium and epicardium. The tricuspid valve is usually normal, and the RV appears thin and dilated.
Functional Impact	The right ventricle loses contractility, cannot generate pressure, and fails to pump effectively → leading to severe right-sided heart failure and low cardiac output.
Pathophysiology	Absence of RV myocardium leads to volume overload of the right atrium, elevated venous pressure, and decreased pulmonary blood flow, resulting in cyanosis and heart failure.
Diagnosis – Clinical	Presents in infancy or early childhood with cyanosis, tachypnea, hepatomegaly, failure to thrive, or arrhythmia. Sudden cardiac death may occur.
Diagnosis – Imaging	Echocardiogram shows a dilated, thin-walled RV with poor systolic function and normal tricuspid valve.
	Cardiac MRI confirms absence of myocardium. CT may also be used to evaluate wall structure.
Treatment	– Supportive therapy (diuretics, oxygen, inotropes) for symptom control

🧪 Multiple Choice Questions

MCQ 1: Embryologic Origin

Which of the following best describes the embryologic defect in Ebstein’s anomaly?

A) Failure of endocardial cushion fusion
B) Failure of myocardial delamination
C) Excessive apoptosis of RV myocardium
D) Persistence of truncus arteriosus

✅ Correct Answer: B) Failure of myocardial delamination

Explanation:
The defect in Ebstein’s anomaly is due to failed delamination of the septal and posterior tricuspid valve leaflets, resulting in downward displacement and valve dysfunction.

Why Incorrect:

• A) Endocardial cushion failure → AV septal defects, not Ebstein’s

• C) Excessive apoptosis → Uhl’s anomaly, not Ebstein’s

• D) Truncus arteriosus → conotruncal defects, not AV valve anomalies

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MCQ 2: Mobile Leaflet

In Ebstein’s anomaly, which tricuspid leaflet is usually enlarged and sail-like?

A) Septal
B) Posterior
C) Anterior
D) All three

✅ Correct Answer: C) Anterior

Explanation:
The anterior leaflet delaminates but is often elongated and mobile, appearing sail-like on imaging.

Why Incorrect:

• A/B) Septal and posterior leaflets are typically tethered and displaced

• D) Only the anterior leaflet remains mobile

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🩺 CLINICAL

MCQ 3: Presentation Features

Which of the following is a common clinical feature in Ebstein’s anomaly?

A) Hypertension
B) Left heart failure
C) Cyanosis and arrhythmia
D) Pulmonary stenosis

✅ Correct Answer: C) Cyanosis and arrhythmia

Explanation:
Due to tricuspid regurgitation and right-to-left shunting across a PFO/ASD, cyanosis occurs. Arrhythmias like WPW are common.

Why Incorrect:

• A) Hypertension is not a typical feature

• B) Left heart is usually unaffected

• D) Pulmonary stenosis can be associated, but is not a primary feature

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MCQ 4: Variable Severity

Which statement best reflects the variability in clinical presentation of Ebstein’s anomaly?

A) All patients present with severe cyanosis in infancy
B) It always leads to heart failure by age 10
C) It may present as severe dysfunction in neonates or remain asymptomatic into adulthood
D) It causes systemic hypertension in adolescence

✅ Correct Answer: C) It may present as severe dysfunction in neonates or remain asymptomatic into adulthood

Explanation:
Ebstein’s anomaly shows wide phenotypic variability. Severe cases present early with cyanosis and failure, while milder forms may go unnoticed for decades.

Why Incorrect:

• A) Not all cases are severe

• B) Heart failure is not inevitable

• D) Hypertension is unrelated

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MCQ 5: Associated Conditions

Which of the following is most commonly associated with Ebstein’s anomaly?

A) Mitral stenosis and bicuspid aortic valve
B) WPW syndrome and atrial septal defect
C) Ventricular septal defect and coarctation of aorta
D) Transposition of the great arteries

✅ Correct Answer: B) WPW syndrome and atrial septal defect

Explanation:
Ebstein’s is often associated with right-sided lesions, especially ASD, PFO, arrhythmias (e.g., WPW), and occasionally pulmonary stenosis or atresia.

Why Incorrect:

• A/C/D: These are associated with other congenital syndromes, not typical of Ebstein’s

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🖼️ IMAGING

MCQ 6: CT Finding

Which of the following CT findings supports the diagnosis of Ebstein’s anomaly?

A) Bicuspid pulmonary valve
B) Thickened mitral leaflets
C) Apical displacement of the tricuspid valve with atrialized RV
D) Septal hypertrophy with mid-cavitary narrowing

✅ Correct Answer: C) Apical displacement of the tricuspid valve with atrialized RV

Explanation:
The key imaging finding is downward displacement of the septal/posterior leaflets → atrialized RV segment visible on CT or MRI.

Why Incorrect:

• A) Pulmonary valve anomalies are not primary features

• B) Mitral valve is usually normal

• D) Suggests hypertrophic cardiomyopathy, not Ebstein’s

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MCQ 7: MRI Utility

What is the primary use of cardiac MRI in evaluating Ebstein’s anomaly?

A) Identifying myocardial scar burden
B) Confirming RV fibrofatty infiltration
C) Measuring tricuspid valve displacement and RV volume
D) Detecting pericardial effusion

✅ Correct Answer: C) Measuring tricuspid valve displacement and RV volume

Explanation:
MRI offers excellent anatomic and functional evaluation, measuring apical displacement and atrialized RV size.

Why Incorrect:

• A) Scar burden is more relevant in ischemic or infiltrative disease

• B) RV fibrofatty change → ARVC, not Ebstein’s

• D) Pericardial effusion is not a primary feature

Memory Images