Chapter 4 · Oversensing · Case 3

Inappropriate therapies during a TAVI procedure

Patient and episode

Patient

  • Hmale implanted with a Resonate triple-chamber defibrillator; trace recorded during a TAVI implantation procedure. The surgery may be called a transcatheter aortic valve replacement (TAVR) or transcatheter aortic valve implantation (TAVI).

Summary

  • Detection of an episode in the VT zone
  • Sequence of bursts then ramps; 41 Joule shock but deflected impact

The recording

Tap a number on the trace, or an entry in the list below

Boston Scientific ICD electrogram, segment 1 of 6 — Inappropriate therapies during a TAVI procedure
Boston Scientific ICD electrogram, segment 2 of 6 — Inappropriate therapies during a TAVI procedure
Boston Scientific ICD electrogram, segment 3 of 6 — Inappropriate therapies during a TAVI procedure
Boston Scientific ICD electrogram, segment 4 of 6 — Inappropriate therapies during a TAVI procedure
Boston Scientific ICD electrogram, segment 5 of 6 — Inappropriate therapies during a TAVI procedure
Boston Scientific ICD electrogram, segment 6 of 6 — Inappropriate therapies during a TAVI procedure
  1. Atrial sensing and biventricular pacing
  2. Sensing of a sharp signal on the 3 channels (atrial, ventricular and shock); this signal corresponds to the ventricular pacing artefact (ventricular capture visible on the shock channel); double counting on the ventricular sensing channel (pacing artefact + subsequent ventricular depolarization).
  3. Alternating VT and VF cycles; the 8/10 criterion is fulfilled for the VT zone but not for the VF zone.
  4. End of duration for VT zone and first ATP sequence delivered
  5. After the ATP sequences, the next therapy is a shock; capacitors begin to charge
  6. Pacing interrupted and cessation of oversensing
  7. Charge diverted (criterion 2/3 rapid cycles at end of charge not confirmed)

Points to remember

  • Aortic stenosis is the most common valvular disease encountered in Western countries, with an estimated prevalence of around 5% among people aged over 75; with an ageing of the population, the prevalence is likely to increase further
  • Since the first percutaneous aortic valve implantation 2002, the indications for TAVI (transcatheter aortic valve implantation) have broadened considerably, resulting in an increase in the number of procedures performed worldwide.
  • During the TAVI implantation procedure, rapid ventricular pacing is usually delivered using a temporary lead positioned in the right ventricle to induce severe, but transient hypotension in order to reduce the risk of embolization of the prosthesis
  • During a TAVI implantation procedure, the implantable defibrillator must be temporarily deprogrammed in order to avoid the occurrence of inappropriate therapies (sensing of pacing artefact, rapid ventricular rhythm, etc.).
  • This type of epiode will typically trigger an optional Lattitude alert “Non physiological right ventricular signal detected” through. because of atleast 4 fast ventricular cycles (<=160ms) before the V-Detect marker.
This figure shows the pacing artefact on all 3 channels and ventricular capture on the shock channel during external pacing
This figure shows the pacing artefact on all 3 channels and ventricular capture on the shock channel during external pacing

Practice out loud

Just describe the tracing. What do you think is going on? Describing the numbers can help.

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From Boston Scientific ICD — clinical cases by P. Bordachar, M. Strik, A. Thiyagarajah, S. Ploux. Published by Cardiocases. Every numbered marker on a recording is explained in the list beneath it; tap a marker on the trace or an entry in the list.

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