EP Staff Education Clinical Staff Ilyas Colombowala, MD, FACC, FHRS →
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Procedure

AV Node Ablation

Catheter ablation of the AV node to produce complete heart block in patients with refractory atrial tachyarrhythmias who already have (or will receive) a ventricular pacing system. A short, high-yield procedure with a predictable workflow.

Typical duration
30 min
Sedation
Moderate sedation

Overview

AV node ablation is one of the shortest procedures we do in the lab, but it has the biggest downstream commitment for the patient: lifelong pacemaker dependence. We perform it when rate control of AF, atrial flutter, or other atrial tachycardias has failed despite optimized medical therapy, and the patient already has — or is receiving — a ventricular pacing system (RV-only, CRT, or conduction-system pacing).

Indications

  • Symptomatic, drug-refractory rapid ventricular response in persistent or permanent AF
  • Tachycardia-mediated cardiomyopathy where rhythm control is not feasible
  • Inappropriate ICD shocks driven by rapidly conducted AF after antiarrhythmic optimization
  • CRT non-response due to low biventricular pacing percentage from breakthrough AF conduction

Pre-procedure prep

  • Confirm device status. If a pacemaker or CRT is already in place, interrogate the morning of the case and document RV (or LV) capture threshold, sensing, and impedance. Borderline thresholds get re-checked before we ablate.
  • If the device is being implanted at the same session, complete the implant and confirm acceptable parameters before moving to ablation.
  • INR or DOAC plan reviewed. AVN ablation does not require interruption of anticoagulation for AF — continue uninterrupted in most cases.
  • NPO per institutional protocol; large-bore peripheral IV; type and screen not routinely required.
  • Pre-procedure ECG and rhythm strip in the chart.

Sterile setup

  • Right femoral venous access only — single 8 Fr sheath is typical.
  • Standard groin prep and drape; a single-site case so no need for full chest field unless device implant is combined.
  • Have a temporary pacing wire and external pacing pads on the patient as backup in case of device malfunction during the case.

Equipment

  • 8 Fr femoral venous sheath
  • Steerable ablation catheter, 4 mm or 8 mm tip (irrigated not required for most cases)
  • RF generator with temperature and power monitoring
  • EP recording system with surface ECG and intracardiac electrograms
  • Programmer for the patient’s pacemaker or ICD
  • Fluoroscopy with LAO and RAO views
  • External defibrillator pads, transcutaneous pacing capability
  • Standard ACLS cart

Technique

  1. Vascular access under ultrasound guidance, single venous sheath.
  2. Pace the device asynchronously (VOO or DOO at 80–90 bpm) before ablation so that transient AV block does not produce a pause. Document the change in the device tracking sheet.
  3. Map the His on the tricuspid annulus from a right-sided approach. We want a clear His electrogram with a small atrial and large ventricular signal.
  4. Pull back slightly toward the AV node — the target is a position with a larger A and a smaller H (the compact AV node), typically 1–2 cm proximal to a robust His signal.
  5. Deliver RF at 40–50 W, temperature limit 60–65 °C, for 30–60 seconds. Look for junctional rhythm within the first 10–15 seconds — this is the marker of effective lesioning.
  6. Confirm complete block. Once AV block is achieved, observe for 10–15 minutes to ensure it is durable. If conduction returns, re-map and re-ablate.
  7. Restore device programming to a paced rate of 80–90 bpm (we will keep this elevated for 1–3 months).

Threshold and endpoint targets

  • Junctional rhythm during ablation is expected and reassuring.
  • Endpoint is sustained complete AV block with the patient pacing reliably and no retrograde conduction.
  • If we get accelerated junctional rhythm without block, stop, reposition slightly distally, and re-energize.

Complications

  • Loss of ventricular pacing — the catastrophic complication; mitigated by pre-ablation device check and asynchronous pacing
  • Pause-dependent polymorphic VT in the early post-procedure window — mitigated by the 80–90 bpm pacing strategy
  • Femoral hematoma, AV fistula, pseudoaneurysm
  • Inadvertent block of the His rather than the AV node (rarely clinically important since we are creating block intentionally)

Post-procedure orders

  • Bed rest with groin pressure per protocol; ambulate at 2–3 hours
  • Telemetry overnight in most cases
  • Device check the next morning to confirm pacing percentage, capture threshold, and sensing
  • Discharge instructions: no driving for 24 hours; pacemaker-dependent precautions reviewed
  • Follow-up device interrogation in 2 weeks, then per device clinic schedule
  • Reduce paced lower rate to a physiologic 60 bpm at the 1–3 month visit

Last reviewed by Dr. Colombowala on May 22, 2026.

Not medical advice. This page is educational. Your situation may differ — discuss it with Dr. Colombowala or your treating physician before making decisions.