Case 3: Bradycardia in a Vigorous Newborn

Leander D. Timothy; Raymond C. Stetson; Muhammad Yasir Qureshi; Stephanie N. Wilkins; Garth F. Asay

doi:10.1542/neo.20-5-e298

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Presentation

A female infant is delivered at 38 weeks and 3 days to a 32-year-old gravida 2, para 1 woman via a low transverse cesarean section. At delivery, the neonate is noted to have a spontaneous cry, appropriate respiratory effort, and active movement of all extremities; however, her initial heart rate is noted to be 40 beats/min.

After drying and stimulation, her oxygen saturation on pulse oximetry is noted to remain at 60% at 3 minutes after birth. Blow-by oxygen is started. Despite this intervention, she develops nasal flaring and subcostal retractions. Facial continuous positive airway pressure (CPAP) is initiated with positive end-expiratory pressure of 5 mm Hg and then the infant is transitioned to nasal CPAP. Oxygen concentration is titrated to 100% and oxygen saturations on pulse oximetry increase to greater than 90%. Her work of breathing normalizes. Apgar scores are noted to be 6 and 8 at 1 and 5 minutes, respectively.

Despite effective ventilation and oxygen saturations, the infant’s heart rate remains between 40 and 50 beats/min. A 12-lead electrocardiogram is obtained, which confirms the diagnosis (Fig 1).

Figure 1.

Electrocardiogram of patient obtained on date of birth.

Discussion

Diagnosis

This infant’s presentation was concerning for a cardiac anomaly, given the intractable bradycardia despite adequate respiratory support, and oxygen saturations. Electrocardiographic findings were consistent with complete heart block (congenital atrioventricular block, third degree). She began receiving an isoproterenol infusion starting at 0.15 μg/kg per minute to increase ventricular rate.

On day 1 after birth, isoproterenol was discontinued to obtain baseline hemodynamics and heart …