Cardiac index and exercise during VDD/DDD versus VVIR pacing in children. The effects of atrioventricular delay

Area of Science:

• Pediatric Cardiology
• Biomedical Engineering
• Electrophysiology

Background:

• Pacemaker therapy is crucial for managing pediatric heart conditions.
• Optimizing atrioventricular (AV) delay in dual-chamber pacing (VDD/DDD) can enhance hemodynamic function.
• Understanding the impact of AV delay on cardiac output and exercise capacity is essential for patient management.

Purpose of the Study:

• To determine the optimal atrioventricular (AV) delay for maximizing cardiac index in pediatric patients with VDD/DDD pacemakers.
• To compare the hemodynamic and exercise performance between VDD/DDD pacing with optimal AV delay and VVIR pacing.

Main Methods:

• Twelve pediatric patients with VDD/DDD pacemakers underwent assessment at various atrioventricular delays (100-200 ms) and VVIR pacing.
• Cardiac index was measured at rest.
• Exercise stress tests were performed to evaluate endurance time.

Main Results:

• VDD/DDD pacing with different atrioventricular intervals significantly increased cardiac index at rest compared to VVIR pacing.
• The optimal atrioventricular delay varied among patients, with 100 ms, 125 ms, 150 ms, and 200 ms being optimal for different individuals.
• Exercise endurance times were comparable between VDD/DDD pacing at optimal AV delay and VVIR pacing.

Conclusions:

• Optimizing atrioventricular delay in VDD/DDD pacing can improve resting cardiac index in pediatric patients.
• While resting hemodynamics benefit from optimized AV delay, exercise capacity does not show significant improvement over VVIR pacing.
• Individualized AV delay optimization is recommended for VDD/DDD pacing in children to enhance cardiac output.