Utilizing stored implanted cardiac defibrillator electrograms to target localized fascicular denetworking in catheter...

Fascicular substrate modification (FSM) by targeting Purkinje-like potentials (PLPs) with radiofrequency (RF) catheter ablation has been shown to be highly effective in the treatment of ventricular fibrillation (VF). It's unclear if targeting the entire Purkinje network is required to achieve the same result particularly in patients with premature ventricular complex (PVC) triggered VF.

This study aimed to examine the utility of the internal cardiac defibrillator (ICD) electrogram (EGM) to target fascicular substrate in the treatment of VF by catheter ablation.

We analyzed stored EGMs captured in patients presenting with recurrent VF or polymorphic ventricular tachycardia (PMVT). Pacemapping at likely sites for PVC triggers of VF using an analysis of the morphology and relative timing of the stored far- and near-field ICD electrograms of VF triggers was used to identify potential culprit locations. Catheter ablation was performed using high power short duration (HPSD) lesions targeting these specific sites, with a focus on modifying the distal fascicular network.

Of 37 patients in our prospective database, 12 underwent EGM-guided FSM. With a mean follow-up of 12 months, there was a 91.7% freedom from PMVT/VF in patients undergoing EGM-guided FSM using HPSD lesions. There was one instance of left posterior hemiblock but no bundle branch block. There was an increased freedom from ventricular arrhythmia in the EGM-guided group compared to controls, but the difference was not statistically significant (91.7% vs. 76.0%, p = 0.27). There was no significant difference between patients undergoing a targeted Purkinje sparing approach compared to those undergoing substrate modification of the entire left-sided Purkinje network (75.0% vs. 85.5%, p = 0.45).

Stored electrogram-guided ablation allows precise localization and modification of fascicular substrate involved in VF and PMVT. This strategy could potentially enhance the efficiency, effectiveness and safety of Purkinje denetworking by catheter ablation.