An x-ray performed on a newborn infant shows enlargement of the left ventricle and left atrium as well as dilatation of the aoa. Echocardiographic studies demonstrate volume-overloading of the left ventricle. Cardiac auscultation reveals the presence of a continuous "machinery" murmur. Which of the following is the most likely diagnosis?
Patent ductus aeriosus (PDA) is a congenital cardiac disorder in which blood traveling in the aoa is shunted through the ductus aeriosus to the pulmonary aeries. On x-ray, the left ventricle and left atrium may be enlarged, and pulmonary hypeension may be observed. PDA is characterized by a continuous "machinery" murmur on auscultation. If the ductus is widely patent, pulmonary hypeension may eventually develop, and the initially left-to-right shunt is reversed, sending deoxygenated blood through the descending aoa, and producing cyanosis (Eisenmenger syndrome). Since the deoxygenated blood enters the descending aoa, the toes can be cyanotic, but the fingers are generally not. In atrial septal defect , left-to-right shunting causes volume overloading of the right ventricle, the increased flow across the pulmonic valve producing a mid systolic pulmonary ejection murmur. The second hea sound is widely split. A diastolic murmur may also be heard, reflecting increased flow from the right atrium into the right ventricle. Pulmonic stenosis typically produces a harsh systolic ejection murmur best heard at the upper left sternal border, often preceded by a systolic ejection sound. Tetralogy of Fallot is a form of cyanotic congenital hea disease characterized by ventricular septal defect, right ventricular outflow tract obstruction, an overriding aoa, and right ventricular hyperophy. The hea is often described as "boot-shaped" on chest x- ray. Ref: Darst J.R., Collins K.K., Miyamoto S.D. (2012). Chapter 20. Cardiovascular Diseases. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.
Atrial septal defect
Patent ductus aeriosus
Pulmonic stenosis
Tetralogy of Fallot