Clarifying the anatomy of the superior sinus venosus defect

Abstract

ObjectivesWe sought to clarify the variations in the anatomy of the superior cavoatrial junction and anomalously connected pulmonary veins in patients with superior sinus venosus defects using computed tomographic (CT) angiography.MethodsCT angiograms of 96 consecutive patients known to have superior sinus venosus defects were analysed.ResultsThe median age of the patients was 34.5 years. In seven (7%) patients, the defect showed significant caudal extension, having a supero-inferior dimension greater than 25 mm. All patients had anomalous connection of the right superior pulmonary vein. The right middle and right inferior pulmonary vein were also connected anomalously in 88 (92%) and 17 (18%) patients, respectively. Anomalous connection of the right inferior pulmonary vein was more common in those with significant caudal extension of the defect (57% vs 15%, p=0.005). Among anomalously connected pulmonary veins, the right superior, middle, and inferior pulmonary veins were committed to the left atrium in 6, 17, and 11 patients, respectively. The superior caval vein over-rode the interatrial septum in 67 (70%) patients, with greater than 50% over-ride in 3 patients.ConclusionAnomalous connection of the right-sided pulmonary veins is universal, but is not limited to the right upper lobe. Not all individuals have over-riding of superior caval vein. In a minority of patients, the defect has significant caudal extension, and anomalously connected pulmonary veins are committed to the left atrium. These findings have significant clinical and therapeutic implications.

Complex connections: A young man presenting with shortness of breath, hypoxemia, right lumbar pain and left limb swelling

“…They usually cause left‐to‐right shunt and are often associated with partial anomalous pulmonary venous drainage from the right lung and with anomalous superior vena cava connection to both the atria 3,4 . A recent study investigated the variety of anatomical presentation of superior sinus venosus defects in 96 patients showing that anomalous connection of the right upper pulmonary vein was present in all cases and superior vena cava frequently over‐rode the atrial septum 5 …”

Superior caval vein partially overriding the interatrial septum–A fetal echocardiographic sign of superior sinus venosus defect. Reporting its rare association with coarctation of aorta in a fetus and its outcome

“…Superior cavoatrial junction defect along with abnormally connected pulmonary veins creates a cone of space between the mouth of the SVC and the superior rim of the oval fossa. There will be variable degree of over‐ride (sometimes no override to greater than 50% over‐ride) of the SVC which is comparable with the aortic over‐ride seen in the setting of tetralogy of Fallot 1 . Complete SVC overriding the interatrial septal is seen in anomalous drainage of entire right SVC into left atrium.…”

Is it really a levoatrial cardinal vein?

“…In the example of the sinus venosus defect, the pulmonary vein, as in the pulmonary‐to‐systemic venous collateral channels, retains its left atrial connection (Figure 5). 16 In the sinus venosus defect, however, the communication with the systemic venous circulation is sufficiently close to the right atrium to produce an interatrial communication, which until very recently was usually described as an “atrial septal defect”, despite the fact that its true morphology had been recognized by Peacock in the middle of the nineteenth century 17…”

“…In the example of the sinus venosus defect, the pulmonary vein, as in the pulmonary-to-systemic venous collateral channels, retains its left atrial connection (Figure 5). 16 In the sinus venosus defect, however, the communication with the systemic venous circulation is sufficiently close to the right atrium to produce an interatrial communication, which until F I G U R E 3 (A) Shows fenestration of the walls of the coronary sinus and left atrium, providing an overflow from the obstructed left atrium in another heart with hypoplastic left heart syndrome. (B) Shows the extreme form of the syndrome of fenestration of the walls of the coronary sinus and the left atrium, an arrangement which leaves the mouth of the coronary sinus functioning as an interatrial communication-the so-called "coronary sinus defect".…”