An adult case of single atrium diagnosed using three-dimensional echocardiography

Previously, complete absence of an interatrial septum (IAS) was thought to be a form of an atrioventricular septal defect involving the cleft mitral valve and interventricular communication. Ellis et al. (1) defined this condition as common atrium (CA). This congenital cardiac anomaly is especially observed in association with heterotaxy syndrome. Levy et al. (2) reported a case of complete absence of IAS without other cardiac defects; however, this condition was different from CA defined by Ellis et al. (1). They used the term single atrium (SA) to denote this anomaly. Two-dimensional transthoracic echocardiography (2-D-TTE) is the preferred imaging method for the examination of IAS and concomittant congenital cardiac pathologies (3). Three-dimensional TTE (3-D-TTE) is a recently introduced tool for examining the heart; it enables the visualization of 3-D, complex and dynamic anatomic aspects of relevant cardiac structures. There has not been any case of SA diagnosed using 3-D-TTE. Here we present a unique case of an adult patient with SA diagnosed using 3-D-TTE.