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Patterns of atrioventricular conduction in children
Insights
This study on pediatric intracardiac electrograms reveals shorter refractory periods and varied atrioventricular conduction patterns in children compared to adults, with some developing Wenckebach block during atrial pacing.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Cardiac Conduction
Background:
- Normal conduction patterns in children are not well-established.
- Understanding pediatric cardiac electrophysiology is crucial for diagnosing and managing arrhythmias.
Purpose of the Study:
- To determine normal intracardiac conduction patterns in children.
- To assess the response to atrial pacing and measure refractory periods.
- To identify patterns of atrioventricular (A-V) conduction.
Main Methods:
- Intracardiac electrograms were performed in 20 children (8 months to 18 years).
- Atrial pacing was conducted in 18 cases.
- Refractory periods and A-V conduction patterns were analyzed.
Main Results:
- Atrial pacing induced AH prolongation in all children.
- Wenckebach block occurred in 11 children at a mean pacing rate of 224 bpm.
- Pediatric refractory periods were shorter than adult values.
- Three types of A-V conduction patterns were observed, with the atrium being the limiting structure in 11 cases.
Conclusions:
- Children exhibit distinct electrophysiological properties compared to adults.
- Atrial pacing can reveal conduction abnormalities in pediatric patients.
- Further research into pediatric cardiac electrophysiology is warranted.
Abstract:
In this study, intracardiac electrograms were performed in 20 children--ranging in age from eight months to 18 years and without evidence of conduction disturbances on the scalar electrocardiogram--to determine the normal conduction patterns, response to atrial pacing, and values of refractory periods. Atrial pacing--18 cases--induced a prolongation al AH on increasing heart rates in all; 11 developed Wenckebach block proximal to the bundle of His at the mean pacing rate of 224 per minute +/- 45 (1 S.D.). Refractory periods were shorter than in adults. Study of the pattern of A-V conduction revealed three types of response: (1) the atrium was the limiting structure in 11 cases; (2) the delay occurred in the A-V node only in four cases; and (3) the delay occurred both in the A-V node and His-Purkinje system. This response was observed in one case only.