Pulmonary Stenosis and Ebstein Anomaly
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Direct answer
Pulmonary stenosis is obstruction to right ventricular outflow at the pulmonary valve, usually producing a crescendo-decrescendo ejection systolic murmur at the left upper sternal border and often an ejection click. Ebstein anomaly is a congenital malformation in which the septal and posterior tricuspid leaflets are displaced apically into the right ventricle, creating an atrialised right ventricle with tricuspid regurgitation. Balloon valvuloplasty is first-line for isolated valvular pulmonary stenosis, while Ebstein anomaly is managed by tricuspid repair or replacement when symptoms or ventricular function demand it.
What you must remember
- Murmur: ejection systolic and crescendo-decrescendo, loudest at the upper left sternal border and radiating to the left clavicle and back.
- Ejection click: present in mobile-valve stenosis and tends to fade as the valve thickens and becomes rigid.
- Second heart sound: P2 is soft or inaudible in severe pulmonary stenosis, which is a useful bedside clue.
- Balloon valvuloplasty: first-line for valvular pulmonary stenosis, usually effective, with some residual regurgitation possible.
- Noonan syndrome: a classic syndromic association, often with a dysplastic pulmonary valve.
- Ebstein anomaly: apical displacement of the septal and posterior tricuspid leaflets, an atrialised right ventricle and a large right atrium.
- Ebstein murmur: holosystolic tricuspid regurgitation at the lower left sternal border, louder on inspiration.
- Associations: lithium exposure in the first trimester and WPW pre-excitation.
Telling two right-sided lesions apart at the bedside
A 24-year-old woman has a systolic murmur on routine examination, and her ECG shows right atrial enlargement. The examiner asks whether the murmur is an ejection murmur from the outflow tract or a holosystolic murmur from the tricuspid valve.
| Feature | Pulmonary stenosis | Ebstein anomaly |
|---|---|---|
| Site of lesion | Pulmonary valve or outflow tract | Tricuspid valve and right ventricle |
| Main murmur | Ejection systolic, crescendo-decrescendo | Holosystolic tricuspid regurgitation |
| Typical ECG | Right ventricular hypertrophy | Right atrial enlargement, pre-excitation |
| Key association | Noonan syndrome | Lithium exposure and WPW |
| Standard treatment | Balloon valvuloplasty | Tricuspid repair or replacement |
Both lesions are right-sided, so the murmur's timing and site decide the diagnosis. An ejection murmur points to the outflow tract, while a holosystolic murmur that increases on inspiration points to the tricuspid valve.
Severity of pulmonary stenosis is judged by the peak transvalvular gradient on echocardiography, and intervention is considered when the gradient is high or symptoms are present. In Ebstein anomaly, the size of the right atrium and the degree of tricuspid regurgitation guide the timing of surgery.
Where the exam tries to catch you
Right-sided lesion questions turn on murmur timing and first-line treatment.
- Trap: Calling the Ebstein murmur an ejection murmur. Correct: It is holosystolic tricuspid regurgitation at the lower left sternal border, louder on inspiration.
- Trap: Choosing surgery first for isolated valvular pulmonary stenosis. Correct: Balloon valvuloplasty is the first-line treatment.
- Trap: Ignoring accessory pathways in Ebstein anomaly. Correct: WPW pre-excitation is frequently associated, so the ECG is read for delta waves.
- Trap: Blaming lithium for every congenital heart defect. Correct: Lithium is specifically linked to Ebstein anomaly in exam questions.
Frequently asked questions
What murmur is typical of pulmonary stenosis?
The murmur of pulmonary stenosis is an ejection systolic murmur, crescendo-decrescendo in shape, heard best at the upper left sternal border. It often radiates to the left clavicle and back, and an ejection click may be present when the valve is mobile.
Which drug taken in pregnancy is linked to Ebstein anomaly?
Lithium taken in the first trimester is linked to Ebstein anomaly, which is a classic exam association. Treatment decisions in pregnancy involve psychiatric and obstetric teams, weighing the risk of the drug against the risk of relapse.
What is the first-line treatment for valvular pulmonary stenosis?
Balloon valvuloplasty is the first-line treatment for isolated valvular pulmonary stenosis and is usually effective. Surgery is reserved for cases where balloon treatment is unsuitable or fails.
Why does the tricuspid murmur of Ebstein anomaly increase with inspiration?
The tricuspid murmur of Ebstein anomaly increases with inspiration because of the Carvallo sign, which applies to right-sided murmurs as venous return to the right heart rises. The murmur is holosystolic and is heard best at the lower left sternal border.