title: Atrial defect size after Blalock-Hanlon atrioseptectomy.
abstract: In transposition of the great arteries, a Blalock-Hanlon closed atrial septectomy is performed to improve intracardiac mixing at the atrial level. Although the Blalock-Hanlon septectomy is a common surgical procedure in cyanotic congenital heart disease, it has not been adequately assessed pathologically. In 14 heart specimens from patients (aged 3 days to 19 years) with transposition of the great arteries and Blalock-Hanlon septectomy, the margins of the septectomy, fossa ovalis and atrial septum were identified. The total area of the septum and its defects was calculated using planimetry. The ratio of defect size to atrial septal area was expressed as percent communication, which ranged from 5 to 39 (mean 18) percent in eight specimens with intact limbus of the foramen ovale and 26 to 57 (mean 42) percent in six specimens in which the limbus had been excised. The finding that specimens in which the Blalock-Hanlon defect extended into the fossa ovalis had the largest total communication emphasizes that to obtain optimal bidirectional atrial mixing the surgeon should extend the Blalock-Hanlon procedure across the limbus into the foramen ovale.
mesh_terms: D002648:Child; D002675:Child, Preschool; D006325:Heart Atria / Q000601:surgery*; D006346:Heart Septum / Q000601:surgery*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008722:Methods; D014188:Transposition of Great Vessels / Q000601:surgery*