Identifying Anomalies of Systemic Venous Drainage Systemic Venous Anomalies; Atrial Morphology

So as to produce totally anomalous systemic venous connection, all of the systemic venous tributaries, along with the coronary sinus, should be connected with the morphologically left atrium. Previous descriptions of this rare constellation of anomalous connections of the systemic venous tributaries of the heart have been compromised by the inclusion of individuals having isomeric atrial appendages. In these settings, most frequently, the totally, or almost totally, anomalous systemic venous connections are associated with a sinus venosus defect. It is the anomalous pulmonary venous connections that then create a venovenous bridge, which permits the systemic venous tributaries to drain into the morphologically left atrium, even though they may be predominantly connected to the right atrium. More rarely, it is feasible for the primary atrial septum to develop so as to leave the systemic venous sinus in direct connection with the body of the morphologically left, rather than the morphologically right, atrium. We report a series of patients potentially falling into the category of anomalous systemic venous connections. The findings show a spectrum from partially to totally anomalous connections, with some better interpreted on the basis of anomalous drainage. Included in our cases, nonetheless, is an autopsied example of totally anomalous systemic venous connection produced by an abnormal location of the primary atrial septum. We discuss the potential morphogenesis for this finding. We emphasize the distinction that needs to be made between anomalous systemic venous connections and anomalous systemic venous drainage.

Automated summary

This article discusses the anomalous systemic venous connections, specifically the connection of the systemic venous tributaries to the left atrium. Previous studies were compromised by the inclusion of individuals with isomeric atrial appendages, leading to inaccurate descriptions. In most cases, the anomalous connections are associated with a sinus venosus defect. Rarely, the primary atrial septum can be located in a way that directly connects the systemic venous sinus to the left atrium instead of the right atrium. The report includes a series of cases potentially falling into the category of anomalous systemic venous connections, with a spectrum of partially to totally anomalous connections. One case is an autopsy example of a totally anomalous systemic venous connection caused by an abnormal location of the primary atrial septum. The article discusses the potential morphogenesis of this finding and emphasizes the distinction between anomalous systemic venous connections and anomalous systemic venous drainage.