A 2-month-old infant is brought to the clinic because of poor feeding, sweating, and difficulty breathing. The parents state that she was doing very well, and has actually been a "very easy going baby", until about a week ago. They assumed that she was developing a "cold", but it has not passed, and the symptoms have been worsening. Cardiac examination reveals a loud, harsh systolic murmur with a thrill that is heard best at the left sternal border. The most likely underlying abnormality is
This patient most likely has a ventricular septal defect, which is the one of the most common acyanotic congenital cardiac anomalies. It is usually due to an opening in the membranous pa of the ventricular septum, and typically leads to symptoms a few weeks after bih, when the pulmonary vascular resistance decreases, and the left-to-right blood shunting increases. The signs and symptoms vary with the size of the defect, and include respiratory distress, failure to thrive, poor feeding, sweating, and a systolic murmur. An echocardiogram confirms the diagnosis. Some small defects close spontaneously, while larger defects may require surgery. Complications include pulmonary vascular obstruction, congestive hea failure, and endocarditis. Critical aoic stenosis (choice A), is more common in boys and is associated with congestive hea failure, and a low-pitched systolic ejection murmur that can be best heard at the second right intercostal space. This murmur is different than the murmur in this case. An atrial septal defect (choice B), is a common acyanotic, left-to-right shunting cardiac anomaly. Infants with this disorder are typically asymptomatic, and it is therefore, diagnosed during a routine examination. There is a systolic ejection murmur that is heard best at the left mid to upper sternal border. There is a wide, fixed split in the second hea sound. Complications include arrhythmias, pulmonary hypeension, and hea failure. The clinical history and findings in this case are inconsistent with this diagnosis. Patent ductus aeriosis (choice D) is usually asymptomatic if it is small. However, a wide pulse pressure, a continuous machinery murmur, apical heave, and a thrill may be present. The patent ductus allows blood to flow from the aoa directly to the pulmonary aery through the ductus aeriosis, (that should normally close by itself immediately after bih). It is typically acyanotic. Indomethacin or surgery is usually indicated to close the ductus.
aoic stenosis
atrial septal defect
ventricular septal defect
patent ductus aeriosis