[Aortopulmonary window vs. persistency of the arterial duct]

On review of the cases of congenital cardiopathies at Hospital General de México, S.S.A., only one case of aortopulmonary fenestration was found and another case of persistence of the arterial duct that was confused with the first diagnosis. Both cases are reported. The world literature on the differential diagnosis of these two and of other malformations with similar clinical manifestations was reviewed. The physical examination of the precordial area and auscultation of murmurs are specially stressed as factors leading to a clinical suspicion of the aortopulmonary septal defect. Comments are made on the clinical hemodynamic course of these two entitites where electrocardiographic and radiological data are similar in both. Thorough hemodynamic studies, catheterization and selective angiography, supply anatomic and pathophysiological data to aid in the correct diagnosis.