What does the figure of 3 sign indicate in cardiology?

The figure of 3 sign is significant in cardiology as it indicates coarctation of the aorta. This radiological finding is observed on chest X-rays and is characterized by a specific contour of the aorta. In cases of coarctation, the aorta typically appears narrowed just after the left subclavian artery, leading to characteristic "figure of 3" shapes due to the presence of pre- and post-stenotic dilatation and the associated anatomical changes.

In a normal aorta, the outline appears more uniform, while in coarctation, the narrowed segment creates this distinctive configuration, leading to the description of the sign. The recognition of this sign is crucial for diagnosis and management, as coarctation can lead to significant complications if left untreated.

Other options listed, such as aortic stenosis, rheumatic heart disease, and pulmonary stenosis, are associated with their own clinical features and radiological signs but do not present the specific figure of 3 pattern that is indicative of coarctation of the aorta. The uniqueness of the figure of 3 sign solidifies its association with this particular cardiovascular condition, helping clinicians identify and address it promptly.