In vitro evaluation of a sensor sensitive to acceleration forces included in a new rate modulated pacemaker

Area of Science:

• Biomedical Engineering
• Cardiovascular Device Technology
• Implantable Electronic Devices

Background:

• Pacemakers are crucial for managing bradycardia and heart rhythm disorders.
• Rate-responsive pacemakers enhance patient quality of life by adjusting pacing rate to physical activity.
• New pacemaker technologies require rigorous evaluation of their sensing and response characteristics.

Purpose of the Study:

• To characterize the sensor and rate-adaptive algorithm of the dual-chamber rate-responsive pacemaker Relay 294-03.
• To evaluate the influence of acceleration frequency, magnitude, and direction on pacemaker rate response.
• To assess the reproducibility of the pacemaker's rate modulation.

Main Methods:

• The Relay 294-03 pacemaker was subjected to calibrated movements simulating various frequencies and accelerations using a mechanical arm.
• Atrial pacing rate was continuously monitored using a Holter monitor during testing.
• Data analysis focused on the relationship between acceleration parameters and pacing rate, including reproducibility.

Main Results:

• The accelerometer sensor demonstrated peak sensitivity at 3 Hz, functioning within a 0.5 to 7 Hz range.
• Pacing rate remained unaffected by frequencies above 6 Hz, distinguishing activity-related signals.
• Rate response increased with acceleration magnitude up to 0.5 G (0.3 G at 3 Hz) and was maximal with anteroposterior acceleration.
• Excellent reproducibility of rate response was confirmed (R2: 0.999).

Conclusions:

• The Relay 294-03 is a rate-modulated pacemaker utilizing a low-frequency sensing accelerometer.
• The device is primarily sensitive to motion in the anteroposterior direction.
• The tested pacemaker exhibits reliable and reproducible rate adaptation based on detected accelerations.