RIGHT-TO-LEFT INTERATRIAL SHUNT WITH NORM AL PULMONARY PRESSURES AFTER PNEUMONECTOMY

Atrial septal defects usually give rise to left-to right in the absenc e of obstruction of the pulmonary outflow tract or pulmonary hypertens ion. The authors report a case of atrial septal defect with a right-to -left shunt despite normal pulmonary pressures at catheterisation in a 56 year-old-man who had undergone left pneumonectomy 6 months previou sly. The shunt was responsible for major arterial desaturation aggrava ted by the left lateral or dorsal decubitus position. Surgical closure of the defect resulted in cure with disappearance of cyanosis and nor malisation of blood gases. The physiopathological mechanisms of these right-to-left shunts with normal pulmonary pressures are discussed wit h reference to previously reported cases in the literature.