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A "multisite" atrioventricular block

Berardo Sarubbi1, Barbara Mercurio, Valentino Ducceschi

  • 1Division of Pediatric Cardiology, Second University of Naples, Italy. berardo.sarubbi@virgilio.it

Italian Heart Journal : Official Journal of the Italian Federation of Cardiology
|April 15, 2004
PubMed

Insights

A pediatric electrophysiologic study revealed significant infra-His conduction delay in a child with a ventricular septal defect. The study identified functional blocks distal to the His bundle, unresponsive to atropine, indicating complex atrioventricular conduction abnormalities.

Area of Science:

  • Pediatric Cardiology
  • Electrophysiology
  • Cardiac Electrophysiology

Background:

  • A 6-year-old child with a history of perimembranous ventricular septal defect presented with atrioventricular (AV) block.
  • The patient exhibited first-degree AV block, bifascicular block, and intermittent episodes of type 1 and type 2 second-degree AV block.

Observation:

  • Electrophysiologic study demonstrated a prolonged HV interval (170 ms), signifying substantial infra-His conduction delay.
  • Spontaneous infra-His type 1 second-degree AV block was observed.
  • During atrial pacing, both supra-His type 1 second-degree AV block and 2:1 infra-His AV block occurred concurrently.

Findings:

  • The observed AV block patterns persisted despite intravenous atropine administration.
  • The conduction delay and block were localized distal to the His bundle.
  • The distal block was characterized as functional, implying a non-structural cause.

Implications:

  • This case highlights complex atrioventricular conduction abnormalities in a pediatric patient post-VSD repair.
  • Understanding functional infra-His conduction delay is crucial for managing AV block in young patients.
  • The findings underscore the importance of comprehensive electrophysiologic evaluation in pediatric cardiac conditions.

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