Respiration as a reliable physiological sensor for controlling cardiac pacing rate

Area of Science:

• Cardiology
• Physiology
• Biomedical Engineering

Background:

• Pacemaker rate control often relies on fixed settings or limited physiological sensors.
• Optimizing cardiac pacing during physical activity is crucial for patient well-being and exercise capacity.

Purpose of the Study:

• To investigate respiration rate as a physiological variable for controlling cardiac pacing rate during exercise.
• To assess the efficacy of respiration rate-driven pacing in improving exercise performance in pacemaker patients.

Main Methods:

• Correlated respiration rate and heart rate in 73 patients undergoing calibrated ergometric tests.
• Utilized a radio frequency-activated, computerised system to adjust pacing rate based on respiration rate in 11 patients.
• Implanted a prototype respiration rate-dependent pacemaker in two patients.

Main Results:

• A significant correlation was found between respiration rate and heart rate across patient subgroups.
• Patients with respiration rate-variable pacing showed increased maximum oxygen uptake, minute ventilation, and work time.
• No significant differences in correlation were observed between patient subgroups with varying lung function.

Conclusions:

• Respiration rate is a valid and stable physiological variable for modulating cardiac stimulation.
• Respiration rate-controlled pacing can enhance cardiac output and exercise capacity in pacemaker-dependent individuals.