Discussion

Neonates born with atrioventricular block and comorbidities like low birth weight, prematurity, and poor haemodynamic status usually have grave prognosis. This subset of neonates needs meticulous attention and aggressive management. Management strategy for haemodynamically significant atrioventricular block includes medical management followed by staged pacing. Medical management includes administration of chronotropic and inotropic support with isoprenaline, dopamine, and dobutamine for neonatal heart block.^{Reference Sivarajah, Huggon and Rosenthal5} Staged pacing can be done with either temporary pacing (epicardial or transvenous approach) or permanent pacing. Planned early pacing of high risk neonates with congenital heart block reduces the adverse consequences of bradycardia and asystole.^{Reference Yildirim, Tunaodlu and Karaadac6} There are several options for pacing ranging from transcutaneous pacing through external defibrillators or temporary pacing catheters via femoral or jugular veins. Temporary pacemaker implantation via umbilical vein can be considered in critically ill neonate as a bridge to a permanent pacemaker. The decision for implanting a device in a neonate is not as straightforward due to many constraints such as patient size, venous access, and haemodynamic instability. Pacing in newborn is generally accomplished with epicardial pacing systems via subxiphoid incision. There have been many reports of implanting epicardial ventricular pacemakers for neonatal congenital heart block since 1973. Epicardial pacing in neonates requires expertise with skilled personnel, and thus in resource-constrained environment, transvenous pacing remains a viable option. However, there are very few studies regarding transvenous approach for temporary pacing in neonates.^{Reference Kannankeril, Dzurik and Fish7,Reference Doshi and Lokare8} Femoral vein and internal jugular vein access are difficult to get and have their own set of complications in newborns. Smaller patients who are less than 6 years are at risk of subclavian vein occlusion when subclavian vein is used to place temporary pacing leads limiting its use in future permanent pacemaker placement through the same route. In light of these findings, pacing via umbilical vein approach is a promising technique as long-term complication of venous occlusion is not of much concern as umbilical vein gets obliterated.^{Reference Kannankeril, Dzurik and Fish7} After stabilisation of the neonate and adequate weight gain, temporary leads can be extracted without any complications and permanent epicardial leads can be implanted as was done in our case.

Our case of premature low birth weight neonate having significant bradycardia with heart rate less than 50 beats per minute and ongoing severe sepsis with metabolic acidosis requiring mechanical ventilator support posed challenges on the management. Early temporary pacing was the feasible option as permanent epicardial pacing could not be considered in this patient due to low birth weight, ongoing sepsis, and haemodynamic instability. There was rapid deterioration in the condition of the neonate, and temporary pacing was done as an emergency procedure. Transvenous pacing via umbilical vein was done to avoid potential complications of larger sheath insertion in femoral vein or internal jugular vein leading to vessel injury. The umbilical vein ensured aseptic access without the need for restriction of the baby or restricting limb movements. This allowed for the stabilisation of the baby and weight gain, before a permanent pacemaker implantation was considered at a later date. There are very few reports of umbilical vein approach for pacing in neonates.^{Reference Li, Zhang and Li4,Reference Kannankeril, Dzurik and Fish7–Reference Hanseus, Sandstrom and Schuller9} Series have been encouraging overall with fewer complications and excellent outcomes.