Case 3: Respiratory Distress and Tachycardia in a Preterm Neonate

A 31-week-gestation male infant is delivered vaginally in the setting of preterm labor and chorioamnionitis. The pregnancy was remarkable for late prenatal care, but no other complications. Maternal antenatal testing results were normal and the mother denied any significant medical history. The infant is initially stunned, but quickly recovers, with Apgar scores of 1 and 7 at 1 and 5 minutes, respectively. His size is appropriate for gestational age and his vital signs in the intensive care nursery include a temperature of 98.8°F (36.5°C), pulse of 172 beats/min, right lower extremity blood pressure of 76/34 mm Hg, respiratory rate of 62 breaths/min, and oxygen saturation of 98% on nasal continuous positive airway pressure support at 5 cm H2O and 21% fraction of inspired oxygen. On examination, the infant’s anterior fontanelle is soft, flat, and approximately 1 fingertip in size. His lungs are clear despite a mildly increased respiratory effort, including grunting and subcostal retractions. He has normal first and second heart sounds, a gallop rhythm, and no murmurs, and his liver is palpable 4 cm below the right costal margin. On investigation, chest radiography demonstrates an enlarged cardiac silhouette (Fig 1), and echocardiography shows findings consistent with restrictive cardiomyopathy, normal systolic function, but impaired diastolic function (Fig 2). Given this rare finding, pediatric cardiology is consulted, which recommends conducting a comprehensive cardiomyopathy genetic testing panel. During his first week after delivery, the infant develops frequent ventricular ectopic beats …