Trigger- vs Substrate-Based Purkinje De-Networking for Ventricular Fibrillation: Insights From a Multicenter Study

Area of Science:

• Electrophysiology
• Cardiology
• Medical Device Technology

Background:

• Purkinje-mediated ventricular fibrillation (VF) can stem from specific fascicular triggers or widespread abnormal Purkinje tissue.
• The effectiveness of trigger-based versus substrate-based de-networking strategies for VF is not well-established.

Purpose of the Study:

• To compare the clinical outcomes of trigger-focused and substrate-based Purkinje de-networking for managing VF.
• To evaluate the efficacy and safety of different ablation approaches for Purkinje-mediated VF.

Main Methods:

• A retrospective multicenter cohort study involving 43 patients undergoing Purkinje-targeted VF ablation with high-power, short-duration radiofrequency energy.
• Patients were categorized into a trigger group (n=19) focusing on culprit fascicles or a substrate group (n=24) targeting all abnormal Purkinje potentials.
• Primary endpoint was recurrence of polymorphic ventricular tachycardia/VF; secondary endpoints included conduction system complications, with a median follow-up of 12.2 months.

Main Results:

• Substrate modification resulted in higher freedom from polymorphic VT/VF (91.7%) compared to trigger-based ablation (63.2%; P=0.026).
• Both strategies significantly reduced arrhythmic burden (P<0.001 for both).
• Conduction complications were more frequent in the substrate group (20.8% new LBBB) versus the trigger group (5.3% posterior fascicular block; P<0.001).

Conclusions:

• Substrate-based de-networking demonstrates superior efficacy in preventing VT/VF recurrence but is associated with increased conduction system injury.
• Trigger-focused ablation may be a suitable initial approach for identifiable triggers, with substrate modification reserved for refractory or non-triggered VF cases.