label: Cor triatriatum dexter
label_lc: cor triatriatum dexter
description: A congenital anomaly with partitioning of the right atrium to form a triatrial heart caused by persistence of the right valve of the sinus venosus. Typically, the right atrial partition is due to exaggerated fetal eustachian and thebesian valves, which together form an incomplete septum across the lower part of the atrium. This septum may range from a reticulum to a substantial sheet of tissue.