Intramural conduction system gradients and electrogram regularity during ventricular fibrillation

Abstract

Our data are supportive of a novel observation of intramural difference between insulated and non-insulated regions of the His-Purkinje network in canines. In addition, certain areas exhibited periods of regular electrogram characteristics; this was despite the heart remaining in terminal VF. These early canine data merit further study to investigate if specific ablation of the distal conduction system can perturb or extinguish VF.

Purkinje tissue modification and ventricular fibrillation

“…The ideal solution would be to selectively destroy the Purkinje tissue, while sparing the precious myocardium. Furthermore, leveraging selectivity for specific conduction tissue such as insulated versus noninsulated tissue, if possible, would offer an increase in both safety and efficacy …”

“…Further compounding this already complex scenario is the difficulty in constructing a reliable model to test and evaluate hypotheses, which is necessary if we hope to usher these into the clinical realm in a safe and effective manner. Animal studies, where VF was induced for euthanasia, have provided data that suggest the importance of the HPS in the maintenance of VF, with the interesting findings that there are differences in the intramural gradients when comparing the proximal, insulated versus the more distal, noninsulated portions of the HPS . Translation of such findings from the animal to the clinical laboratory remains to be seen, and this is on the account of several reasons.…”

“…Perhaps the most optimal model for study is in patients with left ventricular assist devices, though this could be fraught with ethical consequences. Even in this situation, we must consider the underlying cardiomyopathic substrate, duration of VF, and the implications that this will have on the electrophysiology of the myocardium and HPS …”

Mapping ventricular fibrillation ... another piece from the jigsaw

“…In this issue of the Indian Pacing and Electrophysiology Journal, Jason Tri and coll. report their interesting experience in mapping ventricular fibrillation (VF) in dogs [1]. In this model, they demonstrate some intramural differences in activation rate and organisation, as well as between insulated (proximal) and non-insulated (distal) regions of the His-Purkinje network.…”

“…In this model, they demonstrate some intramural differences in activation rate and organisation, as well as between insulated (proximal) and non-insulated (distal) regions of the His-Purkinje network. In addition, some areas have been shown to exhibit periods of regular electrical activity despite continuing fibrillatory pattern on surface ECG [1].…”