pediatric cardiovascular surgery is surgery of the heart of children. the first operations to repair cardio-vascular defects in children were performed by clarence crafoord in sweden when he repaired coarctation of the aorta in a 12-year-old boy. the first attempts to palliate congenital heart disease were performed by alfred blalock with the assistance of william longmire, denton cooley, and blalock's experienced technician, vivien thomas in 1944 at johns hopkins hospital. techniques for repair of congenital heart defects without the use of a bypass machine were developed in the late 1940s and early 1950s. among them was an open repair of an atrial septal defect using hypothermia, inflow occlusion and direct vision in a 5-year old child performed in 1952 by lewis and tauffe. c. walter lillihei used cross-circulation between a boy and his father to maintain perfusion while performing a direct repair of a ventricular septal defect in a 4 year old child in 1954. he continued to use cross-circulation and performed the first corrections of tetratology of fallot and presented those results in 1955 at the american surgical association. in the long-run, pediatric cardiovascular surgery would rely on the cardiopulmonary bypass machine developed by gibbon and lillehei as noted above.