Cardiology · Valvular Heart Disease
The facts most likely to be tested
Pulmonary stenosis presents with a harsh systolic ejection murmur heard best at the left upper sternal border that radiates to the back.
The hallmark physical exam finding is a systolic ejection click that decreases with inspiration.
Severe pulmonary stenosis causes a widely split S2 due to delayed closure of the pulmonic valve.
The murmur of pulmonary stenosis increases in intensity with maneuvers that increase venous return, such as leg raises or squatting.
Noonan syndrome is the most common genetic association with congenital pulmonary stenosis.
Echocardiography is the diagnostic test of choice to confirm the diagnosis and assess the peak pressure gradient across the valve.
Percutaneous balloon valvuloplasty is the definitive treatment of choice for symptomatic patients with moderate to severe stenosis.
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A 6-year-old boy is brought to the clinic for a routine physical examination. On cardiac auscultation, a harsh 3/6 systolic ejection murmur is noted at the left second intercostal space. The murmur is accompanied by a systolic ejection click that decreases in intensity during inspiration. The child has a webbed neck and low-set ears. A widely split S2 is appreciated on examination.
What is the most likely diagnosis?
Pulmonary stenosis
The combination of a systolic ejection murmur at the left upper sternal border, a systolic ejection click, and a widely split S2 is classic for pulmonary stenosis, often associated with Noonan syndrome.
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Etiology / Epidemiology
Almost exclusively congenital; often associated with Noonan syndrome or Tetralogy of Fallot.
Clinical Manifestations
Harsh systolic ejection murmur at the left upper sternal border that increases with inspiration.
Diagnosis
Transthoracic echocardiogram is the gold standard; peak gradient >64 mmHg indicates severe disease.
Treatment
Percutaneous balloon valvuloplasty is the treatment of choice for symptomatic or severe cases.
Prognosis
Generally excellent post-intervention; monitor for right-sided heart failure in untreated severe cases.
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Epidemiology & Etiology
Most cases are congenital valvular stenosis. It is a classic feature of Noonan syndrome and is frequently seen in Tetralogy of Fallot. Acquired causes are rare but include rheumatic heart disease or carcinoid syndrome.
Pertinent Anatomy
Obstruction occurs at the pulmonary valve level, leading to increased afterload for the right ventricle. This results in right ventricular hypertrophy (RVH) to maintain cardiac output.
Pathophysiology
Narrowing of the valve orifice increases the pressure gradient between the right ventricle and the pulmonary artery. Chronic pressure overload leads to RVH and eventually right-sided heart failure. The murmur intensity is directly related to the severity of the stenosis and the volume of blood flow.
Clinical Manifestations
Patients are often asymptomatic until the stenosis is severe. The classic finding is a harsh systolic ejection murmur at the left upper sternal border that radiates to the back. A systolic ejection click may be present, which decreases with inspiration. Syncope, angina, and dyspnea are red flags indicating critical obstruction.
Diagnosis
Transthoracic echocardiogram is the diagnostic test of choice to visualize the valve and calculate the pressure gradient. A peak gradient >64 mmHg is classified as severe. ECG may show right axis deviation and RVH patterns.
Treatment
Mild cases require only observation. Percutaneous balloon valvuloplasty is the first-line intervention for symptomatic patients or those with a peak gradient >60 mmHg. Surgical valvotomy is reserved for patients with dysplastic valves or complex anatomy. Avoid diuretics in patients with severe stenosis who are preload-dependent.
Prognosis
Long-term outcomes are excellent following successful valvuloplasty. Patients must be monitored for pulmonary regurgitation, which is a common sequela of intervention. Annual follow-up is required for those with residual stenosis.
Differential Diagnosis
Aortic Stenosis: murmur radiates to the carotids, not the back
Atrial Septal Defect: fixed split S2, no ejection click
Tetralogy of Fallot: associated with cyanosis and VSD
Hypertrophic Cardiomyopathy: murmur decreases with squatting
Pulmonary Hypertension: loud P2, no ejection click