A Lifeline Through the Umbilicus: Emergency Pacing in Neonatal Complete Heart Block-Uncorrected Proof.

Complete congenital atrioventricular heart block (CHB) is a rare but serious, life-threatening condition in neonates, most often associated with maternal autoimmune connective tissue disease. Definitive management typically requires epicardial pacing; however, in cases of life-threatening bradycardia and hemodynamic compromise, temporary transvenous pacing may be lifesaving. Securing vascular access in premature or low-birth-weight infants often makes vascular access technically challenging, and conventional routes may not always be feasible. In such situations, the umbilical vein offers a rapid, bedside, and less invasive alternative. We present the case of a premature neonate born at 35 + 1 weeks with congenital third-degree heart block, in whom emergency temporary pacing was successfully performed via the umbilical vein after failed femoral access, subsequently serving as a bridge to permanent pacemaker implantation.