Right atrial septal pouch--a potential nidus for thrombosis.

During embryological development, an incomplete fusion of septum primum (SP) and septum secundum (SS) occurring cranially results in an inverted pouch-like structure with its base opening into the right atrium. This has been recently termed as right atrial septal pouch (RASP). Whether this pouch predisposes to intracardiac thrombosis by creating a milieu of localized stasis is unknown. Although some case reports have alluded to thromboembolic potential of left atrial septal pouch with similar origin, there has been no description regarding RASP acting as a thrombogenic nidus. We present a case of thrombus in the RASP with sequential imaging.