Narrow complex tachycardia - Re-entry type

2 yr old, 10 kg. Unbalanced AV septal defect. s/p Takedown of Glenn Operation. Postop. day 5.
Sequence of events during management of tachyarrhythmia:

On Epinephrine, Dobutamine and Milrinone infusions, Digoxin maintenance dose.
Abrupt increase in heart rate from 111/min to 165/min.
Initial diagnosis of SVT. Adenosine (1 mg) administration reveals multipe P waves.
Atrial Flutter is treated with synchronized DC cardioversion (5 Joules).

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