A 7-year-old girl was admitted to the hospital for evaluation of requent respiratory tract infection. She gave past history of pneumonia nd was diagnosed with an atrial septal defect (ASD). Physical examnation revealed mild increase in jugular venous pressure and a grade II/VI holosystolic murmur over the left sternal border. Her electrocariogram showed sinus rhythm with incomplete right bundle-branch lock. Chest roentgenogram showed cardiomegaly, empty superior ight heart border, and fullness in the area above the aortic knob (Fig ). A transthoracic echocardiographic examination revealed a large ight atrium and right ventricle, large coronary sinus and persistence of left superior vena cava (LSVC) draining into the coronary sinus, and arge ASD. Three pulmonary veins were seen and were draining into he left atrium. Routine hematologic and biochemical investigations ere within normal limits. She was scheduled for surgical closure of the ASD. She was induced ith thiopental (2.5%), 60 mg, and midazolam, 2 mg, and intubated fter achieving muscle relaxation with a combination of succinylchoine, 1 mg/kg, and pancuronium, 0.1 mg/kg, with a 5.5 cuffed oral ndotracheal tube (Rusch Inc, Kernon, Germany). The right radial rtery was cannulated for direct arterial pressure monitoring. A tripleumen central venous pressure catheter (Arrow, International), 8 cm, as introduced via the right internal jugular vein (RIJV). Anesthesia as maintained with nitrous oxide and oxygen, morphine, halothane, nd pancuronium. After opening the pericardium, the surgeon noticed bsence of the RSVC and a large PLSVC. After systemic heparinizaion, cardiopulmonary bypass was established by cannulating the aorta, nferior vena cava from the right atrium, and introducing a cannula into he LSVC directly, its tip pointing cephalad. The aorta was crosslamped, and cold antegrade blood cardioplegic arrest was used. The ight atrium was opened, all pulmonary veins were inspected, and were ound to be draining into the left atrium. A large secundum ASD, 2.5 1.5 cm, was closed with a pericardial patch. After rewarming, ardiopulmonary bypass was discontinued on the first attempt with an nfusion of nitroglycerin, 1 g/kg/min. She was ventilated for 4 hours n the intensive care unit and was extubated. She made an uneventful ecovery. On the third postoperative day, contrast medium was injected