What it is
A leadless pacemaker is a small, self-contained pacemaker that lives entirely inside the heart. Imagine a metal capsule about the size of a large vitamin — that is the entire device. Battery, electronics, sensing electrode, and pacing tip are all in one piece, fixed directly to the inner wall of the right ventricle by small flexible tines.
There is no lead wire running through the veins. There is no generator under the skin. There is no scar on the chest. The procedure leaves a small puncture in the groin that heals in a few days.
Two systems are FDA-approved in the United States:
- Medtronic Micra — the first leadless pacemaker. Single-chamber (ventricle only). Two models: Micra VR (single-chamber pacing) and Micra AV (single-chamber device that senses atrial activity through mechanical motion, allowing AV-synchronous pacing in selected patients).
- Abbott Aveir — a newer entrant. Single-chamber (Aveir VR) and dual-chamber (Aveir DR — two leadless devices, one in the right atrium and one in the right ventricle, that communicate with each other). The Aveir is also designed to be retrievable at end-of-life.
Who benefits most
Leadless pacemakers are not for everyone. They make the most sense in specific situations:
- Patients who only need ventricular pacing. Common scenarios: atrial fibrillation with slow conduction, heart block in a patient who already has chronic atrial arrhythmia, AV-node ablation requiring pacing for the ventricle afterward.
- Patients with limited or problematic venous access. Veins scarred by prior catheters, dialysis access, prior lead extractions, or congenital absence.
- Patients with a history of pocket-site infection in a traditional pacemaker.
- Patients who place high value on cosmesis — no chest scar, no visible bulge.
- Older patients who would prefer not to have an arm-restricted recovery and a long incision.
- Patients who need AV-synchronous pacing without a traditional system — Micra AV (single device with motion sensing) or Aveir DR (two devices that talk to each other).
Who is not a good candidate
- Patients who need true atrial pacing in addition to ventricular pacing and aren’t candidates for an Aveir DR setup
- Patients with severe tricuspid valve disease (because the device sits in the right ventricle and crosses the tricuspid valve)
- Patients with mechanical tricuspid valves — leadless devices cannot cross a mechanical valve
- Very small patients whose femoral vein access is limited
- Patients with cardiac conditions where pocket-based monitoring is preferred for follow-up reasons specific to their case
The right device is a conversation. There’s no automatic answer.
The procedure
The implant is done in the EP lab.
- Before. Standard pre-procedure planning — labs, imaging if needed, NPO after midnight, hold anticoagulation per protocol.
- Anesthesia. Local anesthesia at the groin plus conscious sedation. General anesthesia is occasionally used.
- Access. A puncture in the right or left femoral vein.
- Delivery. A flexible delivery sheath is advanced from the groin up to the right ventricle. The device — preloaded inside the sheath — is positioned against the right-ventricular wall, deployed, and tested for stability and electrical performance. If the site isn’t right, the device is recaptured and repositioned.
- Confirmation. Pacing thresholds, sensing, and lead-tip stability are checked. Once everything looks good, the device is released and the sheath is withdrawn.
- Duration. 30–60 minutes from start to finish in routine cases.
Recovery
- Same day or next morning discharge in most patients.
- Bed rest for 2–4 hours after the procedure to protect the groin access site.
- No arm restrictions — there’s no chest pocket to worry about.
- No driving for 24 hours due to the sedation.
- Normal activity within a few days.
- First device check typically at 1 month, then routine remote monitoring every 3–6 months.
What it doesn’t do
A few things to know about what leadless devices currently cannot do well:
- No biventricular pacing. Leadless devices cannot deliver cardiac resynchronization therapy (CRT). Patients needing CRT need a traditional system.
- No defibrillation. Leadless devices pace but do not deliver shocks. Patients needing defibrillation need an ICD (transvenous, subcutaneous, or extravascular).
- No high-output pacing in some edge cases — the battery is smaller, so very high pacing demands deplete it faster.
End-of-life and what happens later
This is the question patients ask most often: what happens when the battery runs out?
The answer depends on the device, the patient, and what other devices have accumulated.
- A second leadless device can be implanted next to the first. The right ventricle is large enough to hold two — sometimes three — leadless pacemakers in different locations. We commonly leave the original in place and add a new one when its battery depletes.
- The original can sometimes be retrieved, particularly with the Aveir system, which is designed with retrievability in mind. Older Micra devices were not designed for routine retrieval and are usually left in place.
- Conversion to a traditional system is always possible if needed — the leadless device is left in the heart and a transvenous system is implanted alongside.
In every scenario the patient continues to be paced — we just choose the best path for that point in their care.
What we monitor over time
Remote monitoring is fully supported for both Micra and Aveir. Most patients get a small home transmitter that wirelessly checks the device daily. We review:
- Battery status
- Pacing thresholds
- Sensing quality
- Episode counts (any tachyarrhythmias detected)
- Patient activity trends
Most follow-ups happen without an in-office visit, with the exception of the 1-month check after implant and annual visits.
When to call us
- Any new symptoms — dizziness, lightheadedness, palpitations
- Bleeding or swelling at the groin in the first few days
- Fever in the first week
- A device alert or remote-monitoring message
- Questions about MRI scans, dental procedures, or other surgeries — both devices are MRI-conditional under specific protocols
- Travel concerns — bring your device card; airport security is not an issue but security personnel sometimes ask
Leadless pacing is one of the genuine recent advances in EP. For the right patient, it’s a quietly elegant solution.