Scimitar syndrome is a congenital heart defect which is characterized by an unusual arrangement of the pulmonary veins. In patients with this condition, one or more of the pulmonary veins from the right lung drains into the side of the heart which normally collects deoxygenated blood from the body so that it can be pushed into the lungs. This causes the heart to work harder than normal, and can lead to enlargement of the heart and other medical issues.
The severity of scimitar syndrome varies considerably. Some people have it and are entirely unaware, or have it diagnosed but a doctor determines that the effects are so minor that no action needs to be taken. In other cases, the defect causes health problems or puts the heart in danger, in which case surgery may be recommended to address the problem. This condition is also known as partial pulmonary venolobar syndrome.
In a patient with pulmonary venolobar syndrome, the veins have a distinctive appearance when they are viewed on X-ray, resembling the Middle Eastern weapon known as a scimitar and explaining the term "scimitar syndrome." The patient's pulmonary veins may drain fully or partially into the wrong side of the heart, and sometimes the heart is located on the right side of the chest instead of the left side. The affected lung and pulmonary veins tend to be smaller than normal, another finding which will be visible on X-ray.
This rare heart defect is usually diagnosed when someone appears to be experiencing heart problems and a doctor orders a medical imaging study to get an idea of what is going on inside the heart. Signs of heart problems can include irregular heartbeats, weakness, dizziness, difficulty breathing, and chest pain. Using an X-ray, a doctor can identify the tell-tale "scimitar sign" which indicates the presence of this defect, and determine how severe it is on the basis of anatomical changes which can be seen in the chest.
Some hereditary factors do appear to be involved with scimitar syndrome. In families with a history of this birth defect, children are more likely to be born with it. In other cases, it appears spontaneously, with no clear familiar history of the condition. It is important to keep in mind that no known family history is not the same as no family history. Someone in the family may have scimitar syndrome, but have such a mild case that it was never identified.