Q: What leadless pacemakers have automatic threshold tracking to demonstrate improved management of nocturnal variations?

Short answer: As of 2025, Medtronic Micra™ leadless pacemakers (VR, AV, and second‑generation VR2/AV2) include Capture Management / Ventricular Capture Management algorithms that automatically measure pacing thresholds at scheduled intervals and adjust output—capabilities that can help manage nocturnal threshold changes. Public documentation for Abbott AVEIR™ devices emphasizes pre‑fixation mapping and implant/clinic measurements; an implanted, fully automatic post‑implant threshold‑tracking algorithm is not clearly described in current materials.

Devices with automatic threshold tracking

Device family	Feature name	What it does
Micra VR (MC1VR01)	Ventricular Capture Management (VCM) / Capture Management	Automatically measures RV capture threshold and adjusts output with a programmable safety margin; periodic checks support energy savings and consistent capture.
Micra AV (MC1AVR1)	Capture Management (RV)	As above, plus atrial mechanical sensing for AV synchrony (not part of threshold tracking).
Micra VR2 / Micra AV2	Capture Management (RV); enhanced algorithms in AV2 for atrial mechanical sensing	Successors with extended longevity; maintain automatic RV threshold management functionality.

These features can be leveraged to schedule night‑time checks or maintain appropriate output during nocturnal threshold rises—subject to model‑specific constraints.

Notes on AVEIR™ devices

What is documented: AVEIR VR/DR materials highlight pre‑fixation mapping (commanded EGM, impedance, and initial capture threshold) to choose the implant site and support retrieval/re‑positioning. Routine follow‑up includes programmer‑based checks.

What is not clearly documented: a continuously running, implanted automatic threshold‑tracking algorithm (like VCM) that autonomously updates output post‑implant. If present in future software, consult the latest manuals.

Why this matters for nocturnal variation

Automatic threshold tracking can detect night‑time rises and maintain capture with small, time‑limited output increases.
Adaptive margins help optimize longevity by lowering output when thresholds are reduced during daytime.
Program within each model’s approved options; verify logs for timing/frequency of threshold checks.

Disclaimer: Educational content; not medical advice.

References (selected)

Medtronic Academy: Ventricular Capture Management (VCM) overview.
FDA SSED for Micra (P150033) detailing VCM objective.
Micra AV Implant Manual noting Capture Management.
Abbott AVEIR VR/DR pages and SSED describing mapping and implant measurements.