Postoperative junctional ectopic tachycardia with variable QRS morphology: A case report.

Junctional ectopic tachycardia (JET) is a rare but clinically important arrhythmia most often encountered in infants and children, either congenitally or within 72 h after congenital heart surgery. We report a neonate who developed postoperative JET with variable QRS morphologies after an arterial switch operation, in whom QP interval and QRS duration correlated with the preceding RR interval. The arrhythmia caused hemodynamic instability requiring antiarrhythmic therapy and supportive measures. This case illustrates the diverse electrocardiographic manifestations of postoperative JET and highlights the importance of early rhythm characterization to guide timely, mechanism-based management in critically ill neonates.