Postoperative junctional ectopic tachycardia

Abstract

MOT CLE Tachycardie jonctionnelle ectopique A 3-month-old boy underwent surgery for correction of a ventricular septal defect. Three hours after the intervention the patient developed a regular narrow QRS complex tachycardia (Fig. 1) with a ventricular rate (V) of 195 bpm and slower, regular atrial activity (A) at 150 bpm. The QRS configuration was similar to previous sinus beats. An atrial electrocardiogram recorded by a postoperative temporary atrial epicardial electrode (lead I) clearly demonstrated dissociation between atrial activity (arrows) and ventricular activity (asterisks), leading to the diagnosis of postoperative junctional ectopic tachycardia (JET). The patient was treated with moderate hypothermia and atrial overdrive pacing. The QRS morphology of the paced beats was similar to that observed during the tachycardia. As expected, atrial pacing did not terminate the arrhythmia; however, the haemodynamic status of the patient improved and he recovered sinus rhythm 89 hours after the onset of tachycardia. The patient’s subsequent postoperative course was uneventful, and he has remained free of new arrhythmic events after five years of follow-up. Rapid (> 170 bpm) postoperative JET has been reported after 1% of congenital heart repairs. Its aetiology is thought to be related to mechanical irritation of the proximal conduction system during surgery. Despite being a transient phenomenon, postoperative JET may lead to serious haemodynamic compromise due to elevated heart rate and loss of atrioventricular synchrony. Electrocardiographic features include QRS configuration similar to conducted sinus or atrial paced beats, along with either atrioventricular dissociation with ventricular rate faster than the atrial rate or retrograde conduction. This arrhythmia does not respond to electrical cardioversion, atrial overdrive pacing or intravenous adenosine, and the efficacy of antiarrhythmic drugs is usually