Dual- vs Single-Chamber Ventricular Pacing in Isolated Congenital Complete Atrioventricular Block in Infancy

Area of Science:

• Pediatric Cardiology
• Electrophysiology
• Congenital Heart Disease

Background:

• The optimal pacemaker strategy for infants with isolated congenital complete atrioventricular block (CCAVB) is not established.
• Dual-chamber pacing (DDD) offers synchrony but may increase ventricular pacing burden, potentially leading to left ventricular (LV) dysfunction in a vulnerable myocardium.

Purpose of the Study:

• To compare clinical outcomes between dual-chamber (DDD) and single-chamber (VVI) pacing in infants with CCAVB.
• To identify risks associated with different pacing strategies in this population.

Main Methods:

• A multicenter retrospective study (2006-2023) included infants with CCAVB implanted with a pacemaker before one year of age.
• Exclusion criteria included significant congenital heart disease and single-site ventricular pacing.
• Outcomes assessed were clinically significant LV dysfunction, mortality, and pacemaker-related complications.

Main Results:

• Of 109 infants (60.6% VVI pacing), 10.1% developed clinically significant LV dysfunction over a median 5-year follow-up.
• LV dysfunction was significantly more frequent with DDD pacing (21% vs. 3%, P=0.006).
• Independent risk factors for LV dysfunction included DDD pacing and neonatal implantation. Complications were more frequent in smaller infants.

Conclusions:

• Dual-chamber (DDD) pacing is associated with an increased risk of LV dysfunction compared to single-chamber (VVI) pacing in infants with isolated CCAVB.
• Single-chamber LV apical pacing should be considered for infants with isolated CCAVB requiring pacing.
• Pacing-related complications are common, with higher risks in low-weight neonates.