A coumadin ridge, also called warfarin ridge or left lateral ridge, is a band-like embryological remnant in the left atrium between the left superior pulmonary vein and the left atrial appendage. It is considered an anatomical variant.
The ridge is formed by the coalition of the left superior pulmonary vein and left atrial appendage, which results in a lateral fold of left atrial wall tissue. The ridge contains the ligament of Marshall, autonomic nerve bundle, and small atrial or sinoatrial node artery.
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Radiographic features
Echocardiography and MRI
The usual appearance of a coumadin ridge is a band-like structure with a thin proximal part and a bulbous distal part that resembles a cotton-tip applicator. This is known as the "Q-tip sign" on transesophageal echocardiogram.
Cardiac MRI using a "bright blood" gradient echo pulse sequence, is useful in demonstrating the ridge. Contrast injection is usually unnecessary but may be helpful in identifying an organized thrombus or tumor in the left atrial appendage.
A prominent coumadin ridge may protrude into the endocardial surface of the left atrium and can be mistaken for a thrombus or mass on imaging 1-5. The unique location of the coumadin ridge between the left superior pulmonary vein and left atrial appendage is an important clue to its identification.
History and etymology
It was called "coumadin" or "warfarin" ridge since it was commonly misdiagnosed as a thrombus, which resulted in unnecessary anticoagulation.
Differential diagnosis
Possible considerations include:
- left atrial thrombus
- left atrial tumors, such as atrial myxoma