A 14-year-old boy presents with decreased exercise tolerance

A 14-year-old boy presents with decreased exercise tolerance. He is noted to have a grade III/VI systolic ejection murmur best heard at the left upper sternal border and a grade II/VI middiastolic murmur at the lower left sternal border. The first heart sound is normal. The second heart sound is widely split and fixed. A right ventricular impulse is palpated. On a chest roentgenogram, the pulmonary artery segment is enlarged, and pulmonary vascular markings are increased. An ECG shows right axis deviation. Which of the following congenital heart diseases does this boy most likely have?

A. Aortic stenosis
B. Atrial septal defect
C. Coarctation of the aorta
D. Patent ductus arteriosus
E. Ventricular septal defect

Explanation: The correct answer is B. One of the most common types of structural congenital heart disease to present in adolescence is atrial septal defect (ASD), and the most common presentation is a heart murmur. However, some patients present with arrhythmias, decreased exercise tolerance, or a paradoxic embolus.

The physical examination can show classic findings of an ASD; in some cases, however, the findings may be extremely subtle. The murmur associated with the ASD is not caused by blood flow traversing the actual defect but rather by the increased volume of blood flow across the pulmonary valve and, to a lesser extent, across the tricuspid valve. Thus, the murmurs of an ASD are a systolic ejection murmur at the upper left sternal border and a mid-diastolic murmur at the lower left sternal border. The second heart sound is widely split and fixed with regard to respiration. On palpation, a right ventricular impulse is present.

The chest radiogram shows evidence of an enlarged pulmonary artery segment in the posteroanterior projection. The superior vena cava shadow may not be visible because of the rotation of the heart secondary to right ventricular volume overload. Pulmonary vascularity is increased, and the heart may be somewhat enlarged. The lateral projection shows the right ventricular enlargement with filling of the retrosternal airspace. The ECG has a normal to rightward axis and a right ventricular volume overload pattern in the precordial leads.

An echocardiogram with color Doppler examination can demonstrate the AS D. However, because the atrial septum is a posterior structure, it may not be visualized adequately with a transthoracic echocardiogram; therefore, a transesophageal echocardiogram is frequently necessary for diagnosis. Closure of the defect is recommended for patients with ASD to decrease the risk of pulmonary vascular obstructive disease, stroke, and arrhythmias.

Aortic stenosis (choice A) is often associated with bicuspid aortic valve and presents with dyspnea on exertion, chest pain, and syncope. A harsh systolic ejection murmur is typically heard at the right upper sternal border.

Coarctation of the aorta (choice C) results in obstruction between the proximal and the distal
aorta. On examination, the femoral pulses are weak and delayed relative to the brachial pulses. Turner syndrome must be considered in a girl with coarctation of the aorta.

Patent ductus arteriosus (PDA) (choice D) usually presents with a “machinery murmur” that is continuous beginning after S1, peaking at S2, and trailing off during diastole. Indomethacin is often effective in closing the PDA in premature infants.

Ventricular septal defect (choice E) is the most common congenital defect of the heart and usually presents with a wide spectrum of symptoms including growth failure, congestive heart failure, and chronic lower respiratory infections. Patients with small defects might be asymptomatic but would have a holosystolic murmur.