Related Experiment Videos
Activity-controlled circadian base rate
E Park1, D Weilenmann, K Bloch
1A St. Jude Medical Company, Cardiac Rhythm Management Division, Sylmar, California, USA. epark@pcnet.pacesetter.com
Pacing and Clinical Electrophysiology : PACE
|November 24, 1998
Summary
The new circadian base rate (CBR) algorithm adjusts pacemaker rates naturally throughout the day. This provides better hemodynamic support during activity and improved rest at night for patients.
Area of Science:
- Cardiology
- Biomedical Engineering
- Physiology
Background:
- Current pacemakers use a fixed base rate, often suboptimal for varying daily patient needs.
- This fixed rate can be too low for daytime activity or too high for nighttime rest.
- Normal individuals exhibit natural fluctuations in resting heart rate throughout the day.
Purpose of the Study:
- To develop and test the circadian base rate (CBR) algorithm for pacemakers.
- To mimic natural circadian heart rate variations in pacemaker patients.
- To optimize hemodynamic support during the day and cardiac recovery at night.
Main Methods:
- Utilized sophisticated accelerometer sensors in Trilogy DR+ pacemakers.
- Collected and analyzed activity data from 25 pacemaker patients over a week.
- Applied the CBR algorithm to activity variance histograms to determine base rates.
Main Results:
- The CBR algorithm generated base rates below 100 ppm, similar to natural sinus rate distributions.
- The algorithm successfully created a circadian rhythm in paced heart rates.
- Achieved higher daytime rates for support and lower nighttime rates for recovery.
Conclusions:
- The CBR algorithm effectively models natural circadian heart rate variations in pacemaker patients.
- This algorithm offers improved physiological pacing by adapting to daily activity levels.
- Optimized pacing rates enhance both daytime function and nighttime recovery.