We present a case of small coronary sinus defect detected after transcatheter device closure of a large secundum atrial septal defect. Although device erosion of the dilated coronary sinus is suspected, the defect in the coronary sinus may have been present prior to ASD device closure. Dilated coronary sinus may be a risk factor when closing a secundum ASD with a device. To the best of our knowledge, coronary sinus erosion by an ASD device has not yet been reported in the medical literature.
Keywords: Amplatzer Septal Occluder; Atrial septal defect; Coronary sinus; Unroofed coronary sinus.