Related Experiment Video

Updated: Jul 10, 2026

Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction
06:57

Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction

Published on: January 31, 2019

Vulnerability to electric shocks in the regionally-ischemic ventricles

Blanca Rodríguez1, Brock Tice, Robert Blake

  • 1Oxford University, UK. blanca@comlab.ox.ac.uk

Conference Proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
|October 20, 2007
PubMed

Insights

Defibrillation in ischemic hearts shows unchanged upper limit of vulnerability (ULV) but an expanded vulnerable window (VW). This increased cardiac vulnerability post-LAD occlusion is due to slow conduction and dispersion of refractoriness.

Area of Science:

  • Cardiovascular Physiology
  • Computational Biology
  • Electrophysiology

Background:

  • Defibrillation is crucial for treating cardiac arrhythmias, yet its efficacy in ischemic heart disease remains poorly understood.
  • Ischemic heart disease significantly alters cardiac electrical properties, potentially impacting defibrillation success.

Purpose of the Study:

  • To investigate the impact of regional ischemia on cardiac vulnerability to defibrillation shocks.
  • To understand the mechanisms behind defibrillation failure in the early stages of ischemia following Left Anterior Descending (LAD) occlusion.

Main Methods:

  • Development of a 3D anatomically accurate, electrophysiologically detailed bidomain model of the ischemic ventricles.
  • Simulation of ventricular pacing and application of monophasic shocks to determine the upper limit of vulnerability (ULV) and vulnerable window (VW).
  • Comparison of ULV and VW in normoxia versus 10 minutes post-LAD occlusion.

Main Results:

  • The ULV remained unchanged 10 minutes post-LAD occlusion, as virtual electrode polarization and post-shock behavior were unaffected by ischemia at high shock strengths.
  • The VW significantly increased from 60 ms in normoxia to 90 ms at 10 minutes post-occlusion.
  • Increased cardiac vulnerability in regional ischemia is linked to slow conduction and dispersion of refractoriness, promoting reentrant circuit formation.

Conclusions:

  • Early regional ischemia does not alter the ULV but significantly expands the VW, increasing susceptibility to defibrillation failure.
  • The findings highlight the complex electrophysiological changes during ischemia that enhance vulnerability to arrhythmias.
  • This study provides crucial insights into defibrillation challenges in ischemic heart disease, guiding future therapeutic strategies.

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