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Q-T interval in congenital complete heart block
Insights
Prolonged Q-Tc interval in children with congenital complete heart block indicates a worse outcome and may predict symptoms. This finding is crucial for understanding congenital heart block prognosis in pediatric patients.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Congenital Heart Disease
Background:
- Congenital complete heart block (CCHB) is a serious condition in children.
- The rate-corrected Q-T interval (Q-Tc) is a measure of ventricular repolarization.
- Understanding prognostic markers in CCHB is vital for patient management.
Purpose of the Study:
- To investigate the prognostic significance of prolonged Q-Tc in children with CCHB.
- To correlate Q-Tc interval with symptoms and outcomes in this population.
- To assess the relationship between Q-Tc, ventricular rate, and clinical presentation.
Main Methods:
- Retrospective analysis of 273 children diagnosed with congenital complete heart block.
- Measurement and analysis of rate-corrected Q-T interval (Q-Tc).
- Comparison of Q-Tc intervals and ventricular rates between patients and age-matched controls.
Main Results:
- Fifty-nine out of 273 children had a prolonged Q-Tc, with 50 experiencing symptoms.
- Children with prolonged Q-Tc had a significantly lower ventricular rate (VR) compared to controls.
- A prolonged Q-Tc was associated with a worse outcome, especially when combined with a low VR.
Conclusions:
- Prolonged Q-Tc in children with CCHB is a significant indicator of poor prognosis.
- Elevated Q-Tc may precede symptomatic presentation by over a month.
- Q-Tc interval assessment is valuable for risk stratification in pediatric congenital heart block.
Abstract:
The rate-corrected Q-T interval (Q-Tc) was measured in 273 children with congenital complete heart block. Fifty-nine had prolonged Q-Tc and 50 of these had symptoms. All 10 with isolated complete heart block, prolonged Q-Tc and bundle branch block had symptoms. The ventricular rate (VR) was significantly lower in patients with prolonged Q-Tc than in their age-matched controls. The outcome is worse for children with low VR and long Q-Tc than for those with low VR and normal Q-Tc. In 11 children a prolonged Q-Tc preceded symptoms by more than 1 month. This suggests that prolonged Q-Tc in children with congenital complete heart block can be of prognostic significance.