A left superior caval vein frequently occurs in the malformed, as well as in the structurally normal, heart. Its physiological impact varies, and is determined by its connections and whether there are associated cardiac lesions. In this review, we describe 3 patients with such a vein, 1 without other lesions and 2 with the anomalous venous channel as a component of a complex cardiac malformation. In all cases, transcatheter techniques were used to treat the physiological dysfunction caused by the presence of the vein. The connections of the vein, and the complexity of the associated cardiac lesions, determine the options for treatment. We define the role of surgical as opposed to transcatheter intervention, and discuss strategies for transcatheter treatment.