Giant Eustachian valve and Thebesian valve-A highly deceptive structures as atrial septal defect rims.

The Eustachian valve (EV) of the inferior vena cava and the Thebesian valve (TV) of the coronary sinus are incompletely regressed structures of embryonic sinus venosus. In the majority of cases, the EV and TV disappear completely after birth or are represented only by a thin crescentic fold. On echocardiography, these vestiges may mimic abnormal structures. We report a case with giant EV and TV which were initially misinterpreted as rims of an atrial septal defect (ASD) leading to the false diagnosis of ostium secundum ASD.

Case report - azygos vein drainage into the left atrium in a dog with cor triatriatum dexter and a patent foramen ovale.

A 2-year-old Airedale terrier was presented with exercise intolerance since birth and newly developed chylous pleural effusion. Imaging procedures including echocardiography, cardiac magnetic resonance imaging, computed tomography, and selective angiography revealed an aberrant connection of the azygos vein and the left atrium, a membrane in the right atrium consistent with cor triatriatum dexter, and a patent foramen ovale with right-to-left shunt. Balloon dilation of the membrane in the right atrium seemed to result in transient improvement of exercise tolerance compared with the previous 2 years. When chylothorax relapsed after three months, the dog was euthanized. Necropsy confirmed the azygos vein to left atrial connection, the patent foramen ovale, and the cor triatriatum dexter.