Physical activity detection in patients with intracardiac leadless pacemaker

Area of Science:

• Cardiology
• Biomedical Engineering

Background:

• The Micra Transcatheter Pacing System utilizes a three-axis accelerometer for rate-adaptive pacing.
• Individual programming of activity vectors is essential for optimal system performance.

Purpose of the Study:

• To evaluate the short- and mid-term performance of the Micra activity sensor's three available vectors.
• To determine the efficacy of individual vector testing versus relying on the nominal Vector 1.

Main Methods:

• Prospective collection of implantation and follow-up data from 51 patients.
• Exercise tests were conducted at predischarge and follow-up visits for each activity vector.
• Vectors were categorized as adequate or poor based on activity counts.

Main Results:

• Initial testing showed adequate quality for nominal Vector 1 in 74.5% of patients.
• At follow-up, Vectors 1 and 3 showed comparable adequate quality (64.7% vs 68.6%), outperforming Vector 2 (51.0%).
• In VVIR mode, Vector 1 was initially selected in 46.7%, Vector 3 in 44.4%, and Vector 2 in 8.9% of patients.

Conclusions:

• Rate-adaptive pacing with the Micra system is feasible with manual selection of an adequate activity vector.
• Vector testing in Micra patients with chronotropic incompetence is beneficial over using the nominal Vector 1.