We describe a 7-week-old female infant who presented with refractory supraventricular tachycardia (SVT). During amiodarone infusion, she developed hypotension and cardiac arrest requiring extracorporeal membrane oxygenation (ECMO) support. After successful control of SVT using procainamide infusion, she was weaned from ECMO and discharged home on oral flecainide. We conclude that infants with acidosis, ventricular dysfunction, and prolonged refractory SVT may poorly tolerate intravenous amiodarone.