A Two-Month-Old Infant with Respiratory Distress and Left Ventricular Hypertrophy

A 2-month-old male presented to the emergency department with wheezing and dyspnea at the end of September. The birth history was significant for parental report of possible gestational diabetes mellitus, birth weight greater than the 97th percentile for age at 4.66 kg, and a difficult delivery because of shoulder dystocia. The patient had respiratory distress soon after birth requiring positive pressure ventilation, but this quickly resolved. There was no history of exposure to prenatal steroids and no jaundice, abnormal body odor, or muscle weakness after birth. The family history was significant only for maternal hypertension and no other known heart disease. There was no consanguinity between the parents. When the 2-month-old infant presented to our hospital, his temperature was 99.1 F, the heart rate was 135 beats/ min, the respiratory rate 52 breaths/min, the blood pressure was 112/53 mm Hg, and the oxygen saturation was 97% in room air. His weight was 5.1 kg (50th percentile), length was 56 cm (75th percentile), and head circumference was 37.5 cm (75th percentile). He was active, alert, and feeding without difficulty. Mild wheezing and transmitted upper airway sounds were auscultated throughout both lung fields with good aeration bilaterally. There was a grade II/VI systolic ejection murmur at the cardiac base with normal first and second heart sounds. There were good brachial and femoral pulses without brachiofemoral delay. The abdomen was soft, non-tender, and without hepatosplenomegaly or any masses. The result of his neurologic examination was grossly normal. The initial evaluation included a chest radiograph that revealed marked cardiomegaly with clear lung fields. An electrocardiogram was then obtained and showed marked biventricular hypertrophy (Figure 1). Blood pressures were then obtained in all 4 extremities and ranged from 80 to 135 mm Hg systolic without a trend. Pediatric cardiology consultation was requested because of the cardiomegaly and abnormal electrocardiogram. The echocardiogram showed marked left ventricular hypertrophy with mild left ventricular outflow obstruction (Figure 2). Workup for ventricular hypertrophy started with a careful review of available birth records. Although the patient was large for gestational age, there were no laboratory tests con-