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Cardiorespiratory response to exercise in congenital complete atrioventricular block
T Reybrouck1, B Vanden Eynde, M Dumoulin
1Department of Pediatric Cardiology, Gasthuisberg University Hospital, University of Leuven, Belgium.
The American Journal of Cardiology
|October 15, 1989
Summary
Children with congenital complete atrioventricular block have reduced cardiorespiratory endurance. Exercise testing reveals subnormal heart rates and oxygen uptake, indicating exercise intolerance due to inadequate hemodynamic adjustment.
Area of Science:
- Pediatric Cardiology
- Exercise Physiology
Background:
- Congenital complete atrioventricular (AV) block can affect cardiovascular function in children.
- Assessing exercise capacity is crucial for managing pediatric heart conditions.
Purpose of the Study:
- To evaluate cardiorespiratory endurance and exercise response in children with congenital complete AV block.
- To determine the utility of exercise testing in assessing exercise intolerance in this population.
Main Methods:
- Treadmill exercise testing was performed on 8 pediatric patients (ages 8-17) with congenital complete AV block.
- Cardiorespiratory endurance was assessed using ventilatory threshold.
- Heart rate and oxygen uptake were measured during exercise.
Main Results:
- Patients exhibited significantly lower ventilatory thresholds compared to normal values (p < 0.005).
- Resting heart rates were low (36-56 bpm), with a mean exercise heart rate of 106 bpm.
- Heart rates were subnormal at all exercise levels, and oxygen uptake was significantly lower than in controls (p < 0.02).
Conclusions:
- Congenital complete AV block is associated with reduced cardiorespiratory endurance and exercise intolerance.
- Exercise testing is valuable for assessing exercise bradycardia and intolerance, as resting heart rate is insufficient for prediction.