Baffle leaks may be present after repair of anomalous pulmonary venous drainage and atrial switch operation. While obstruction of systemic or pulmonary venous return after the Mustard or Senning operation has been reported in up to 16 % of patients, baffle leaks in this setting were found in approximately 10 %. Both lesions may be present in combination [1]. Shunt direction and shunt portion depend on defect size and hemodynamics determined by ventricular filling characteristics and associated pathologies. Additional obstructions have particular impact and may cause right-to-left shunt. These patients are at risk for paradoxical embolic events or may be cyanotic and present with secondary erythrocytosis, but the latter findings are rare. Given the increased risk of thromboembolism after permanent pacemaker implantation, every patient after atrial switch operation should meticulously be examined with echocardiography and catheterization because smaller leakages may easily be missed. Defects can virtually occur at all sites of central venous return [2], but are more often located at superior or inferior caval connection [3]. They can however also be found in the central part of the baffle, where posteriorly the pulmonary veins may be accessible and anteriorly the adjacency to the AV valves has to be considered. Reoperation is associated with higher risk and mortality; hence, interventional therapy advanced to primary treatment option in most cases.