Clinical evaluation of a pacemaker algorithm that adjusts the pacing rate during sleep using activity variance.

Area of Science:

• Cardiology
• Biomedical Engineering
• Sleep Medicine

Background:

• Rate-responsive pacemakers adjust pacing based on sensor data but lack automatic rate reduction during sleep.
• The "Sleep Rate" feature aims to provide lower pacing rates during sleep periods.

Purpose of the Study:

• To evaluate the performance of the "Sleep Rate" feature in pacemakers.
• To compare pacemaker-derived sleep data with wrist actigraphy and patient diaries.

Main Methods:

• 19 patients with Pacesetter Trilogy DR+ pacemakers were studied, with base and sleep rates set to 80 and 50 ppm.
• Pacemaker data and wrist actigraphy were analyzed for agreement in sleep/wake periods.
• Epoch-by-epoch comparison assessed concordance between pacemaker and actigraphy data.

Main Results:

• 89% of patients entered sleep mode, but pacemaker-derived sleep time was significantly shorter than actigraphy-derived sleep time (307.3 vs 1156.8 minutes).
• Frequent reversions out of sleep mode limited sustained rate reduction.
• Good agreement (93.6%) was found during wakefulness, but only 24.6% epoch agreement during sleep.

Conclusions:

• The "Sleep Rate" feature offers rate reduction during sleep but current algorithms are limited by frequent mode reversions, hindering sustained slow pacing.
• Improvements are needed in future pacemaker algorithms to allow longer periods of slow pacing during continuous sleep.
• The feature ensures rapid rate response during physical activity without significant patient-reported adverse events.