Author: Anna Hartzog MD and Chinwe Unegbu MD – Children’s National Hospital


An 8-month-old male with Tetralogy of Fallot (TOF) with hypercyanotic spells presents for complete surgical repair. Preoperatively, the patient has a baseline heart rate of 160-170. Induction of anesthesia is uneventful, and the patient is initiated on a dexmedetomidine infusion following intubation. After 120 minutes on cardiopulmonary bypass with a cross clamp time of 79 minutes, the patient is separated from bypass and is noted to be in normal sinus rhythm, have a core temperature of 37.8°C, and have a low calcium level. Which factor in this patient is MOST LIKELY to be protective against the development of postoperative junctional ectopic tachycardia (JET)?