Long-Term Follow-Up of Second-Degree Heart Block in Children

Area of Science:

• Pediatric Cardiology
• Electrophysiology
• Cardiac Electrophysiology

Background:

• Outcomes for children with second-degree heart block are not well-understood.
• Structurally normal hearts in pediatric patients with Mobitz 1, 2:1, or Mobitz 2 block require further risk assessment for progression.

Purpose of the Study:

• To assess the risk of progression to complete heart block (CHB) or pacemaker (PM) placement in children with specific types of second-degree heart block.
• Identify predictors of adverse outcomes in pediatric patients with concerning second-degree heart block.

Main Methods:

• Retrospective review of an institutional electrophysiology database (2009-2021).
• Inclusion criteria: children with Mobitz 1, 2:1, or Mobitz 2 block on ambulatory rhythm monitoring, with or without other conduction abnormalities.
• Primary outcome: composite of CHB or PM placement during follow-up.

Main Results:

• 30% of the 20 analyzed patients progressed to CHB or required a PM.
• Patients who progressed were more likely to have second-degree block at maximum sinus rate (67%), below normal average heart rate (67%), and 2:1 block on initial ECG (50%).
• Median follow-up was 5.8 years.

Conclusions:

• A significant proportion of children with concerning second-degree heart block may progress to CHB or require a PM.
• Second-degree block at maximum sinus rate, bradycardia, and initial 2:1 block are associated with higher risk of progression.
• Further monitoring and risk stratification are crucial for these pediatric patients.