Rate-adaptive cardiac pacing in children using a minute ventilation biosensor.

Area of Science:

• Pediatric Cardiology
• Biomedical Engineering
• Exercise Physiology

Background:

• Chronotropic competence is crucial for maintaining cardiac output during physical activity.
• Pediatric bradycardia, due to complete heart block or sinus node dysfunction, necessitates effective pacing solutions.
• Rate-adaptive pacemakers aim to mimic physiological heart rate responses to exercise.

Purpose of the Study:

• To evaluate the efficacy of a minute ventilation-based rate-adaptive ventricular demand pacemaker (Telectronics, META-MV) in young patients.
• To determine if minute ventilation can accurately reflect metabolic demands and guide pacing in children.
• To assess the pacing rate response during exercise and recovery in pediatric patients.

Main Methods:

• Seven young patients (mean age 11.4 years) with bradycardia underwent exercise testing with the META-MV pacemaker.
• Pacing rate was adjusted based on minute ventilation, a measure of respiratory rate and volume.
• Heart rate, workload, oxygen consumption (VO2), and minute ventilation were monitored during exercise and recovery.

Main Results:

• Paced heart rates increased significantly from 70 ± 10 beats/min to 151 ± 19 beats/min during exercise.
• Rate adaptation occurred rapidly, with onset in under 30 seconds.
• Changes in pacing rate showed a linear correlation with workload, VO2, and minute ventilation.
• Pacing rate reduction post-exercise was directly related to decreases in minute ventilation and VO2.

Conclusions:

• Minute ventilation serves as a reliable and accurate indicator of metabolic demand during varying workloads in children.
• The Telectronics META-MV pacemaker effectively provides physiological, rate-adaptive pacing in pediatric patients.
• Minute ventilation-triggered pacing is a viable strategy for managing bradycardia in children during physical activity.