Scimitar syndrome

Abstract

A 66-year-old man presented with a non-resolving right lower lobe infiltrate. The chest radiograph showed prominent central pulmonary arteries (PA) with normal tapering into the periphery and a typical scimitar-shaped shadow in the right lung (figure A, arrows). On auscultation we heard a soft systolic ejection murmur over the pulmonic area and a soft mid-diastolic flow murmur at lower sternum, suggesting a left-to-right shunt. Echocardiography showed a dilated right ventricle (RV) with normal kinetics and a systolic pressure gradient between the right ventricle and atrium of 25 mm Hg. We excluded an atrial septal defect. The left ventricle and all heart valves were normal. Contrast-enhanced electrocardiogram-triggered ultrafast multi-slice CT showed a dilated pulmonary artery (trunk diameter 36 mm), dilated RV and the scimitar vein (SV) at the level of its confluence with the inferior vena cava (IVC) (figure B). In the coronal plane (figure C), the anomalous SV could be visualised in its entire course to the IVC; the picture also shows the dilated PA. The three-dimensional image reconstructed from the CT (figure D) showed that nearly all venous return from the right lung was directed via the anomalous SV to the IVC just above the diaphragm. The left pulmonary veins drained normally into the left atrium (LA). At catheter-isation, a left-to-right shunt ratio of 48% due to the anomalous pulmonary venous drainage through the SV was confirmed. Corrective surgery (redirecting the scimitar vein into the left atrium) was not done in our patient because he had no symptoms, no coexistent cardiovascular anomalies or pulmonary hypertension, and a low shunt ratio.The scimitar syndrome is a congenital anomalous connection of the pulmonary vein with the inferior vena cava. On the chest radiograph, the vein produces a vascular shadow to the right of the heart that descends toward the diaphragm, resembling a scimitar, which is a short curved Turkish sword. In the adult, it is most often a benign anomaly usually discovered as an incidental finding. The scimitar syndrome should be considered in the presence of an atypical right paracardial shadow on the posteroanterior chest radiograph; contrast-enhanced CT with 3-dimensional reconstruction establishes the diagnosis. A 66-year-old man presented with a non-resolving right lower lobe infiltrate. The chest radiograph showed prominent central pulmonary arteries (PA) with normal tapering into the periphery and a typical scimitar-shaped shadow in the right lung (figure A, arrows). On auscultation we heard a soft systolic ejection murmur over the pulmonic area and a soft mid-diastolic flow murmur at lower sternum, suggesting a left-to-right shunt. Echocardiography showed a dilated right ventricle (RV) with normal kinetics and a systolic pressure gradient between the right ventricle and atrium of 25 mm Hg. We excluded an atrial septal defect. The left ventricle and all heart valves were normal. Contrast-enhanced electrocardiogram-triggered ultrafast multi-slice CT showed a dilated pulmonary artery (trunk diameter 36 mm), dilated RV and the scimitar vein (SV) at the level of its confluence with the inferior vena cava (IVC) (figure B). In the coronal plane (figure C), the anomalous SV could be visualised in its entire course to the IVC; the picture also shows the dilated PA. The three-dimensional image reconstructed from the CT (figure D) showed that nearly all venous return from the right lung was directed via the anomalous SV to the IVC just above the diaphragm. The left pulmonary veins drained normally into the left atrium (LA). At catheter-isation, a left-to-right shunt ratio of 48% due to the anomalous pulmonary venous drainage through the SV was confirmed. Corrective surgery (redirecting the scimitar vein into the left atrium) was not done in our patient because he had no symptoms, no coexistent cardiovascular anomalies or pulmonary hypertension, and a low shunt ratio. The scimitar syndrome is a congenital anomalous connection of the pulmonary vein with the inferior vena cava. On the chest radiograph, the vein produces a vascular shadow to the right of the heart that descends toward the diaphragm, resembling a scimitar, which is a short curved Turkish sword. In the adult, it is most often a benign anomaly usually discovered as an incidental finding. The scimitar syndrome should be considered in the presence of an atypical right paracardial shadow on the posteroanterior chest radiograph; contrast-enhanced CT with 3-dimensional reconstruction establishes the diagnosis.