Unroofed coronary sinus

Sinus venosus defects (SVDs), originally described in 1858, represent about 2%–10% of all atrial septal defects.1 The remainder is composed of ostium secundum (70%), ostium primum (20%) and unroofed coronary sinus (<1%) defects. Approximately 90% of SVDs are associated with partial anomalous pulmonary venous return (PAPVR).2 The superior SVD (SSVD) variant results from communication between the superior vena cava (SVC)-right atrial (RA) junction and the left atrium and is associated with PAPVR from the right upper lung lobe into the systemic venous circulation. Inferior SVDs are less common and result from anomalous communication of the RA and inferior vena cava (IVC) junction with the left atrium. They are less commonly associated with PAPVR of the right lower lobe pulmonary vein into the IVC.

A 50-year-old woman was found to have a heart murmur during examination as part of a preoperative assessment for a knee replacement. She was asymptomatic and had led an active lifestyle as a basketball player for many years prior to her knee problems. An echocardiogram demonstrated a dilated right ventricle (RV) and good left ventricular systolic function. A multi-gated acquisition (MUGA) scan confirmed the presence of RV dilatation and ECG demonstrated right-bundle branch block but was otherwise unremarkable. The patient had a family history of heart disease as well as sudden cardiac death and hence initially the possibility of arrhythmogenic right ventricular dysplasia was raised.Cardiac MRI and subsequent CT was performed and revealed an anomalous connection between the SVC-RA junction and the left atrium, representing an SSVD. Note was made of associated partial anomalous pulmonary venous drainage. The right superior pulmonary vein, an accessory right upper and the right middle pulmonary vein were all seen to drain into the SVC high up, close to the innominate vein confluence (figure 1, videos 1 and 2). Because of this considerable distance from the RA appendage, it was felt that the Warden procedure might result in excessive tension of the anastomosis. A double pericardial patch technique was therefore used (figure 2). The patient made a very good recovery following surgical intervention. Postoperative follow-up echocardiography demonstrated decrease in size of the RV.