Scimitar syndrome

Scimitar syndrome, also known as pulmonary venolobar syndrome or congenital venolobar syndrome, is a rare congenital heart defect characterized by anomalous pulmonary venous return from the right lung to the inferior vena cava rather than to the left atrium. The name derives from the characteristic curvilinear shadow on chest X-ray that resembles a Turkish scimitar sword, created by the anomalous draining vein. The syndrome primarily affects the cardiovascular and pulmonary systems and is frequently associated with additional anomalies including right lung hypoplasia, dextroposition of the heart (shift of the heart to the right due to the small right lung), anomalous systemic arterial supply to the right lung from the aorta, and other congenital cardiac defects such as atrial septal defect. Scimitar syndrome presents in two main clinical forms. The infantile form typically manifests in the first year of life with symptoms of heart failure, pulmonary hypertension, tachypnea, recurrent respiratory infections, and failure to thrive, and tends to carry a more severe prognosis. The adult or childhood form is often milder and may be discovered incidentally on chest imaging, with patients remaining asymptomatic or experiencing only mild exertional dyspnea. Some patients develop recurrent right-sided pneumonias due to the associated pulmonary anomalies. Treatment depends on the severity of symptoms and the degree of left-to-right shunting. Asymptomatic patients with minimal shunting may require only monitoring. Surgical intervention is indicated for significant hemodynamic compromise and may include reimplantation of the anomalous vein into the left atrium, baffling of the anomalous venous drainage through an atrial septal defect, or in severe infantile cases, pneumonectomy of the hypoplastic right lung. Coil embolization of anomalous systemic arterial supply may also be performed. Outcomes are generally favorable for the childhood/adult form, while the infantile form carries higher morbidity and mortality, particularly when associated with pulmonary hypertension and additional cardiac malformations.

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