A<unk>  is a communication between the right and left atrium. Despite the communication between the two atria, it is not considered an atrial septal defect as the septal tissue is not missing.
Patent foramen ovale
Perforated septum
Atrial myxoma
Ductus arteriosus aneurysm
Aneurysm of sinus of valsalva
Annuloaortic ectasia
Right ventricular outflow tract tachycardia
Left ventricular aneurysm