Which patient does the emergency department nurse assess first?

The patient presents to the emergency department (ED) after a hard workout lifting weights complaining of chest pain. An electrocardiogram is performed and cardiac enzymes are drawn. The patient’s myoglobin level is found to be elevated. Which interpretation of this result is most appropriate?

A neonate is born at full term to a mother who did not receive prenatal care. The neonate required moderate resuscitation at birth. Upon assessment, the nurse notes poor muscle tone, a protruding tongue, low nasal bridge, and low-set ears. A loud continuous “machine-like” heart murmur is heard. The patient requires 85% FiO2 to maintain an oxygen saturation above 90%. Which of the following tests is the next best diagnostic step in the management of this patient?