For which of the following congenital cardiac defects may spontaneous closure of the ductus arteriosus be catastrophic?
I.Tetralogy of Fallot with pulmonary atresia
II.Atrial septal defect
III.Severe coarctation of the aorta
IV.Hypoplastic left heart syndrome

Question

Quizplus · Accepted Answer

Shunting is potentially harmful,either due to prolonged cyanosis and decreased end organ oxygen delivery,or to increased PVR over time.However,shunting also has an important compensatory effect in patients with obstructed pulmonary or systemic blood flow.In these lesions,referred to as ductal-dependent lesions,the presence of a PDA provides lifesaving blood flow.Lesions with systemic outflow tract obstruction,such as critical coarctation of the aorta or hypoplastic left heart syndrome,rely on the PDA to provide systemic blood flow via a right-to-left shunt;these lesions have ductal-dependent systemic blood flow.With both right-to-left shunt (cyanotic cardiac defect)and left-to-right shunt (acyanotic cardiac defect),several lesions depend on a patent ductus arteriosus for adequate pulmonary and systemic blood flow.These anomalies are also called ductal-dependent lesions because spontaneous closure of the ductus arteriosus can prove catastrophic.Anomalies included in this group are severe coarctation of the aorta,hypoplastic left heart syndrome,and tetralogy of Fallot with pulmonary atresia.

For Which of the Following Congenital Cardiac Defects May Spontaneous