Frontiers in Physiology (Apr 2024)

A porcine large animal model of radiofrequency ablation-induced left bundle branch block

  • Felix Wiedmann,
  • Felix Wiedmann,
  • Felix Wiedmann,
  • Max Jamros,
  • Valerie Herlt,
  • Amelie Paasche,
  • Amelie Paasche,
  • Manuel Kraft,
  • Manuel Kraft,
  • Moritz Beck,
  • Merten Prüser,
  • Merten Prüser,
  • Merten Prüser,
  • Atilla Erkal,
  • Maren Harder,
  • Marcin Zaradzki,
  • Jasmin Soethoff,
  • Matthias Karck,
  • Norbert Frey,
  • Norbert Frey,
  • Norbert Frey,
  • Constanze Schmidt,
  • Constanze Schmidt,
  • Constanze Schmidt

DOI
https://doi.org/10.3389/fphys.2024.1385277
Journal volume & issue
Vol. 15

Abstract

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BackgroundElectrocardiographic (ECG) features of left bundle branch (LBB) block (LBBB) can be observed in up to 20%–30% of patients suffering from heart failure with reduced ejection fraction. However, predicting which LBBB patients will benefit from cardiac resynchronization therapy (CRT) or conduction system pacing remains challenging. This study aimed to establish a translational model of LBBB to enhance our understanding of its pathophysiology and improve therapeutic approaches.MethodsFourteen male pigs underwent radiofrequency catheter ablation of the proximal LBB under fluoroscopy and ECG guidance. Comprehensive clinical assessments (12-lead ECG, bloodsampling, echocardiography, electroanatomical mapping) were conducted before LBBB induction, after 7, and 21 days. Three pigs received CRT pacemakers 7 days after LBB ablation to assess resynchronization feasibility.ResultsFollowing proximal LBB ablation, ECGs displayed characteristic LBBB features, including QRS widening, slurring in left lateral leads, and QRS axis changes. QRS duration increased from 64.2 ± 4.2 ms to 86.6 ± 12.1 ms, and R wave peak time in V6 extended from 21.3 ± 3.6 ms to 45.7 ± 12.6 ms. Echocardiography confirmed cardiac electromechanical dyssynchrony, with septal flash appearance, prolonged septal-to-posterior-wall motion delay, and extended ventricular electromechanical delays. Electroanatomical mapping revealed a left ventricular breakthrough site shift and significantly prolonged left ventricular activation times. RF-induced LBBB persisted for 3 weeks. CRT reduced QRS duration to 75.9 ± 8.6 ms, demonstrating successful resynchronization.ConclusionThis porcine model accurately replicates the electrical and electromechanical characteristics of LBBB observed in patients. It provides a practical, cost-effective, and reproducible platform to investigate molecular and translational aspects of cardiac electromechanical dyssynchrony in a controlled and clinically relevant setting.

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