Serpentinous structure in the right atrium.

Thin, slender, filament like structure is common finding in right atrium echocardiographically. These structures generally represent embryological remnants like thebasian valve, eustachian valve and chiari network. Apart from these variants, they can also be initial finding of thrombotic process specially in the presence of central venous catheter. Early detection and removing the catheter can prevent further thromboembolism in such cases.