Transcatheter Sinus Venosus ASD Closure. A case series of first ever transcatheter closure of the defect in PakistanDr Muhammad Waleed BabarAFIC/NIHD, Rawalpindi, PakistanMail ID: babarov786@gmail.comDr Saima RafiqueAFIC/NIHD, Rawalpindi, PakistanKhurram AkhtarAFIC/NIHD, Rawalpindi, PakistanMaimoona SaeedAFIC/NIHD, Rawalpindi, PakistanAmjad MehmoodAFIC/NIHD, Rawalpindi, PakistanAbubakar SadiqAFIC/NIHD, Rawalpindi, PakistanAzizullahAFIC/NIHD, Rawalpindi, PakistanKey Clinical Message:This case series highlights three cases of first ever transcatheter sinus venosus closure in Pakistan, giving detailed insight to the procedure performed. It underscores the importance of the fact that transcatheter closure of this defect can easily be achieved, significantly reducing patient’s morbidity as opposed to open heart surgery.Introduction:Sinus venosus atrial septal defect is a congenital anomaly which results from abnormal communication between both the atria and is always associated with partial anomalous pulmonary venous return. This defect is surgically closed using patch closure and relocating the pulmonary veins to the left atrium (LA). Transcatheter closure has been achieved through placement of a covered stent in the SVC1 . In 2013, Abdullah et al 2 described an innovative technique successfully used in 4 patients, where covered balloon-expandable stents were deployed across the superior cava–right atrial junction, replacing the deficient posterior wall and redirecting flow from the RPVs to the left atrium. Subsequently, there have been several case reports and small series 3,4,5 describing the application of this approach. We report first ever transcatheter sinus venosus atrial septal defect closure in the the country. These novel procedures were performed with the assistance of a foreign proctor at the Armed forces institute of Cardiology, Rawalpindi, Pakistan.Case no 1:Case History and Examination:The first case was a 30 year old male. He presented with left sided chest pain along with exertional dyspnea. He underwent 2D as well as transthoracic echocardiography which showed sinus venosus ASD with the right upper pulmonary veins draining into the SVC-RA junction while the rest of the veins draining normally into the left atrium. His cath data showed a Qp:Qs 1.5:1 and PVR 1.4 wum2 . CT angiography was done which revealed sinus venosus defect with the anomalous venous drainage.(Figure 1)