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[Prolonged Q-T interval with functional A-V block in neonates and young infants (author's transl)]
Insights
This study identifies a rare pediatric arrhythmia characterized by a prolonged Q-T interval and atrioventricular (A-V) block, leading to dangerous heart rhythms like torsades de pointes.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Genetics
Context:
- A prolonged Q-T interval and second-degree atrioventricular (A-V) block were observed in five pediatric patients.
- Arrhythmia was detected prenatally or in early infancy, often presenting with syncopal attacks.
Purpose:
- To describe a rare syndrome of unknown etiology characterized by A-V block secondary to delayed repolarization (prolonged Q-T interval).
- To highlight the risks of torsades de pointes and ventricular fibrillation associated with this condition.
Summary:
- Five children presented with a prolonged Q-T interval and second-degree A-V block, complicated by torsades de pointes.
- Outcomes varied, with one fatality, one requiring a pacemaker, and three recovering spontaneously or with propranolol treatment.
Impact:
- This syndrome's originality lies in the A-V block caused by delayed repolarization.
- Effective management involves beta-adrenergic blocking agents and temporary or permanent pacemakers.
Abstract:
A prolonged Q-T interval (0.56 to 0.70 s.) with second degree A-V block was present in 5 children. Auscultation in utero (2 cases) or at birth (1 case) and syncopal attacks at 15 days and 2 months of life led to the discovery of the arrhythmia which was complicated with torsades de pointes. One patient died at 1 month of age; another is treated with propranolol and an internal pacemaker; the last 3 recovered, either spontaneously or with propranolol. The originality of this syndrome of unknown etiology is due to the A-V block, secondary to delayed repolarization (prolonged Q-T interval). Torsades de pointes and ventricular fibrillation are the main risks. Treatment includes beta adrenergic blocking agents associated with a temporarily implanted pacemaker. In a few cases, the internal pacemaker has to be left permanently.