Situs ambiguous with three chambered heart (single atrium), evaluation by four-dimensional X-strain color echocardiography – A case report

Situs ambiguous accounts for 4% of all congenital heart disease (CHD) and has an incidence of 1:10,000 new born births. To standardize the nomenclature for CHD, the international nomenclature society published a globally accepted nomenclature tree for CHD with the 11th Iteration of international classification of disease. According to this publication common atrium, single atrium and atrium communis are denoted as synonyms. The incidence of common atrium among atrial septal defect (ASD) patients is 3–4% only and thus denoting it to be a rare entity. We are presenting an exceedingly rare case of a patient of situs ambiguous, left isomerism, and single atrium with a cleft on the anterior mitral leaflet, evaluated comprehensively by four-dimensional X-strain color Doppler echocardiography.