Cor triatriatum is a rare congenital heart defect in which a thin, fibro-muscular membrane divides the left or right atrium into two chambers resulting in a triatrial heart. Subdivision of the left atrium named cor triatriatum sinister (CTS), is the more common form, whereas the right atrial equivalent called cor triatriatum dexter (CTD) is rarer. They account for up to 0.4% and 0.025% of the burden of congenital heart disease respectively. We present the case of CTD found incidentally with transthoracic echocardiography for a patient who underwent aortic valve replacement for symptomatic bicuspid aortic valve stenosis.

Cor triatriatum (CT) or a triatrial heart is a rare congenital anomaly in which one of the atrial chambers is divided by a fibromuscular membrane. Of the two variants, CT dexter (right-sided CT) is still further rare than CT sinister (left-sided CT). Although CT sinister presents with features of left heart obstructive disease mimicking mitral stenosis, CT dexter is usually asymptomatic and is found incidentally on imaging. Here, we present a patient with an unusual case of complete heart block who was found to have CT dexter along with right ventricular noncompaction on imaging.

Congenital heart disease (CHD) seriously threatens fetal health. Therefore, prenatal examination to detect deformity is extremely important. The present study aimed to investigate the clinical application value of prenatal ultrasonography combined with molecular biology methods in the diagnosis of fetal CHD. A total of 1,000 pregnant women who had received fetal ultrasonography to examine fetal CHD were enrolled. Ultrasounds were performed for fetal heart examination and diagnosis, mainly on fetal heart position, size, structure and function, and heart valve morphology and function. These indexes were tested again 2 weeks after birth. Blood samples were collected from pregnant women with fetal CHD. Polymerase chain reaction (PCR) and western blotting were performed to detect the association between heart development and T‑box transcription factor 1 (TBX1) expression. The results revealed that 10 fetuses had CHD (1%), of which ultrasound detected 9 cases. The specificity and sensitivity of ultrasounds were 100 and 90%, respectively. Of the 9 cases were identified by prenatal ultrasound screening, including 2 cases had endocardial cushion defect, 1 case had pulmonary stenosis combined with right ventricular dysplasia, 1 case had tetralogy of Fallot combined with a cleft lip and palate, 2 cases had ventricular septal defect, 1 case had a single ventricle defect, 1 case had Ebstein and 1 case had a triatrial heart. One case of ventricular septal defect was missed prior to delivery. PCR and western blotting demonstrated that TBX1 expression may be associated with CHD. Therefore, ultrasonography combined with laboratory examinations represent efficient, economic and safe methods for fetal CHD detection. These methods may be significant to improve the rate of CHD diagnosis, and require further investigation.

Cor triatriatum sinister is a rare congenital lesion encountered in children. It consists of a fibromuscular membrane that separates the left atrium into two chambers resulting in a triatrial heart and often occurs with other structural cardiac anomalies. The acquired form is uncommon and has only been reported after orthotopic heart transplantation or as a complication of infective endocarditis in adults. These cases were mostly because of hypertrophied atrial tissue or suture lines and torsion of the atrium. We describe the first case of acquired cor triatriatum late after the Fontan procedure with successful surgical resection in a child.