Exercise capacity in children with isolated congenital complete atrioventricular block: does pacing make a...

Area of Science:

• Pediatrics
• Cardiology
• Exercise Physiology

Background:

• Congenital complete atrioventricular block (CCAVB) management has evolved, with pacing often based on exercise capacity.
• Previous data on exercise capacity in CCAVB patients are limited, often from small series of unpaced individuals.

Purpose of the Study:

• To investigate the exercise capacity of contemporary children diagnosed with congenital complete atrioventricular block (CCAVB).
• To compare exercise parameters in paced and unpaced children with CCAVB against healthy peers.

Main Methods:

• Sixteen children with CCAVB underwent echocardiography and cardiopulmonary cycle exercise testing.
• Exercise parameters including peak oxygen uptake and ventilatory threshold were measured.
• Results were compared to reference values from healthy Dutch children.

Main Results:

• Children with CCAVB exhibited reduced peak oxygen uptake (79% of predicted) and ventilatory threshold (78% of predicted).
• Peak workload relative to body mass was similar to controls (91% of predicted).
• Twenty-five percent of paced patients experienced upper rate restriction; paced and unpaced children showed similar exercise performance.

Conclusions:

• Children with CCAVB demonstrate impaired aerobic capacity (peak oxygen uptake and ventilatory threshold) but normal peak workload.
• This suggests a greater reliance on anaerobic energy production during exercise in this population.
• Pacemaker implantation did not confer a performance advantage in the studied children with CCAVB.