The team has been called to the ED after a 12-month old is brought in with a rapid heart rate. The team will realize the patient is in a stable SVT rhythm, with no response to either vagal maneuvers or adenosine. The patient will then progress to having an unstable SVT. If the SVT is defibrillated (i.e. – shocked without synchronization), the patient will progress to VT arrest. If the SVT is cardioverted, the patient will clinically improve.