Leadless Pacemakers and Extravascular ICDs: Safe Coexistence for Ventricular Fibrillation Prevention

Strategic Insights -

Researchers at Scripps Memorial Hospital have made significant breakthroughs in the development of leadless pacemakers and extravascular implantable cardioverter-defibrillators (ICDs). These innovations offer promising alternatives for patients requiring both defibrillation and pacing, particularly those unable or unwilling to accommodate traditional leads. However, the interactions between extravascular ICDs and leadless pacemakers remain largely unexplored and currently lack regulatory approval for combined use. This study evaluates the interactions between leadless pacemakers and extravascular ICDs to assess their simultaneous operation.

Key Takeaways:

  • The research found that pacing pulses 3V and 0.24 ms had minimal impact on ventricular fibrillation (VF) detection.
  • Experiments confirmed that pacing pulses 3V and 0.24 ms had a pacing pulse-to-VF amplitude ratio of 2, which was considered safe.
  • Wider pulse widths or higher outputs progressively increased the risk of VF undersensing.
  • Proximity of the device affected the pacing pulse amplitude sensed by the ICD, but pacemaker orientation did not.
  • Monte Carlo simulations indicated a 0-4% probability of undesired interactions under clinically relevant conditions.
  • The study concluded that extravascular ICDs and leadless pacemakers may safely coexist with a low observed risk of VF undersensing.
  • However, further clinical studies are needed to confirm these findings.

Statistics:

  • 0-4% probability of undesired interactions between extravascular ICDs and leadless pacemakers under clinically relevant conditions.
  • 3V and 0.24 ms pacing pulse width was considered safe for VF detection.
  • 2:1 pacing pulse-to-VF amplitude ratio was considered safe for VF detection.

Sources:

  • "Extravascular implantable cardioverter and leadless pacemaker interactions." Europace, 2025. Oxford Univ Press, Great Clarendon St, Oxford OX2 6DP, England.
  • Medical Devices & Surgical Technology Week. "Researchers at Scripps Memorial Hospital Detail Findings in Ventricular Fibrillation (Extravascular implantable cardioverter and leadless pacemaker interactions)." November 2, 2025; p 1693. NewsRx LLC.