Purpose:To report the management of junctional ectopic tachycardia after cardiac surgery in an infant.Postoperatively, the patient suffered profound cardiac decompensation secondary to the accelerated rhythm and required extracorporeal membrane oxygenation (ECMO) for haemodynamic support. Clinical features: A 14-day-old, 3.5 kg boy exhibited junctional ectopic tachycardia after cardiopulmonary bypass. Left atrial pressure was 25-28 mmHg. No impact on the tachycardia was seen after rapid overdrive atrial pacing or after 20 ~g fentanyl iv, 45/Jg digitalis, 100 mg magnesium or procainamide (loading dose 15 mg, then 30 mg'kg-~'min-~). Active cooling decreased the nasopharyngeal temperature to 35.2~ when the heart rate decreased below 180 bpm with a left atrial pressure of 8-10 mmHg. Dopamine (2/ag.kg -I.min -I) and dobutamine (5/Jg'kg -I min -I) were added to improve the cardiac output. Sodium nitroprusside (0.25 to I Hg-k,g -I .min) maintained the systolic pressure < 100 mmHg. On arrival in ICU, heart rate increased to 200 bpm. The patient received cardiac massage for severe hypotension 75 min after surgery. Emergency ECMO was instituted for circulatory support. Procainamide, digoxin, dopamine, dobutamine, sodium nitroprusside and hypothermia were continued. Sinus rhythm resumed on the first postoperative day, but procainamide and induced hypothermia at 34~ were maintained for 36 hr after normalization of the rhythm to prevent recurrence of the tachycardia. Total duration of ECMO was three and a half days. Recovery was uneventful. Conclusion: The use of ECMO, as a first line of defence, is suitable for the emergency support of patients with JET because of the ease of support of circulation and precise control of hypothermia.Objectif : D&rire le traitement d'une tachycardie ectopique jonctionnelle (TEJ) survenue chez un enfant, apr~s une chirurgie cardiaque, alors qu'il a souffert d'une profonde d&ompensation cardiaque secondaire au rythme acc~l&~ eta eu besoin d'oxyg~nation extracorporelle (OEC) pour un soutien h~modynamique. Aspects cliniques : Un garcon de 14 jours, pesant 3,5 kg, a pr&ent~ une tachycardie ectopique jonctionnelle la suite d'une circulation extracorporelle. La pression auriculaire gauche &ait de 25-28 mmHg. II n'y a pas eu d'impact sur la tachycardie ~ la suite de I'ent~nement ~lectrosystolique auriculaire rapide ou radministration de 20 Hg de fentanyl iv, 45 Hg de digitale, 100 mg de magn&ium ou de proca'~'namide (dose d'attaque de 15 mg, suivie de 30 mg'kg -I'min-~). Le refroidissement actif a diminu~ la temp&ature nasopharyngienne ~ 35,2~ tandis que la fr~quence cardiaque a diminu~ sous 180 bpm avec une pression auriculaire gauche de 8-10 mmHg. La dopamine (2/~g'kg -~ .min -I) et la dobutamine (5 Hg.kg -~ 'min -I) ont am~lior~ le d~bit cardiaque. Le nitroprussiate de sodium (0,25 ~ I ~g.kg -~ .min) a maintenu la pression systolique < 100 mmHg. A I'arriv& ~ rUSI, la fr~quence cardiaque a augment~ ~ 200 bpm. Le patient a re~u un massage cardiaque pour une hypotension s~v~re, 75 min apt& la chirur...