Rate adaptive pacing in an intracardiac pacemaker.

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• The Micra transcatheter pacemaker offers VVIR pacing functionality using an internal accelerometer for rate adaptation.
• It detects patient activity and cardiac motion to adjust pacing rates.

Purpose of the Study:

• To evaluate the performance of the Micra pacemaker's rate-adaptive pacing during maximal exertion treadmill tests.
• Assess the system's ability to match pacing needs with patient activity levels.

Main Methods:

• Patients underwent treadmill testing at 3 or 6 months post-implant.
• Sensor rate (SenR) was modeled against normalized workload (METS).
• Proportionality was assessed by comparing the slope of SenR to METS against a tolerance margin.

Main Results:

• 69 tests were conducted on 42 patients.
• 30 tests (20 patients) showed proportionality with an average slope of 0.86 (90% CI: 0.77-0.96).
• 83.3% of individual tests had normalized slopes within the acceptable range (0.46-1.08).

Conclusions:

• Accelerometer-based rate-adaptive pacing demonstrated proportionality to workload.
• Rate-adaptive pacing commensurate with workload is achievable with an entirely intracardiac pacing system.