Stepwise analysis of the calibration procedure of an accelerometer-based pacemaker

Area of Science:

• Biomedical Engineering
• Medical Device Technology

Background:

• The Relay 294-03 device modulates its pacing rate based on acceleration signals.
• Accurate calibration is essential for reliable device performance and clinical interpretation.

Purpose of the Study:

• To investigate the impact of moderate acceleration levels (MAL) during calibration on the device's rate modulation.
• To analyze how calibration influences sensor amplifier gain and maximum programmable pacing rate (PR).

Main Methods:

• Device calibration involved volunteers with varying activity levels (seated, walking, jogging) to establish different MAL.
• Mechanical testing subjected the device to calibrated movements across its sensitivity spectrum.
• The influence of slope on device response was assessed through repeated movements.

Main Results:

• Moderate acceleration levels (MAL) significantly affected subsequent rate modulation (P = 0.0001).
• Higher MAL resulted in lower sensor amplifier gain and lower PR for equivalent accelerations.
• Lower amplifier gain improved the ability to detect higher accelerations before sensor overflow.
• Decreasing MAL increased the maximum achievable PR, shifting the rate response curve (RRC) calibration point earlier.

Conclusions:

• The calibration procedure is crucial for defining moderate acceleration intensity.
• Calibration determines sensor amplifier gain and the maximum achievable programmable pacing rate (PR).
• Proper calibration enhances the clinical utility of the Relay 294-03 device.