What is the clinical evidence from this study?

Study design: Other. Population: Myocardial scar (n=8). Intervention: Pulsed field ablation (PFA) vs. Ungated PFA applications. Primary outcome: Sustained ventricular arrhythmias requiring defibrillation.

January 1, 2023Open Access

Electrophysiology, Pathology, and Imaging of Pulsed Field Ablation of Scarred and Healthy Ventricles in Swine

Key Result

Ventricular pulsed field ablation successfully penetrated myocardial scar, and QRS-gated delivery eliminated sustained ventricular arrhythmias compared to ungated applications (0% vs 2.1%).

Structured PICO

Does QRS-gated pulsed field ablation safely penetrate ventricular scar without inducing arrhythmias in a porcine model?

Population

8 swine (5 with coronary occlusion infarct scar, 1 with radiofrequency ablation iatrogenic scar, 2 healthy controls)

Intervention

Bipolar, biphasic pulsed field ablation (PFA) (2.0 kV) using an 8 Fr focal catheter, delivered over scarred and healthy myocardium

Comparator

Ungated vs QRS-gated PFA applications

Outcome

Ability of ventricular PFA to penetrate scarred tissue, induction of ventricular arrhythmias, and MRI assessment of lesionssurrogate

In a porcine model, pulsed field ablation successfully penetrates ventricular scar tissue, and QRS-gated delivery eliminates the risk of PFA-induced ventricular arrhythmias.

Main Result

Absolute Event Rate: 0% vs 2.1%

Abstract

BACKGROUND: Pulsed field ablation (PFA) has recently been shown to penetrate ischemic scar, but details on its efficacy, risk of arrhythmias, and imaging insights are lacking. In a porcine model of myocardial scar, we studied the ability of ventricular PFA to penetrate scarred tissue, induce ventricular arrhythmias, and assess the influence of QRS gating during pulse delivery. METHODS: Of a total of 6 swine, 5 underwent coronary occlusion and 1 underwent radiofrequency ablation to create infarct scar and iatrogenic scar models, respectively. Two additional swine served as healthy controls. An 8 Fr focal PFA catheter was used to deliver bipolar, biphasic PFA (2.0 kV) lesions guided by electroanatomical mapping, fluoroscopy, and intracardiac echocardiography over both scarred and healthy myocardium. Swine underwent magnetic resonance imaging 2-7 days post-PFA. RESULTS: =0.53). PFA penetration of both infarct and iatrogenic radiofrequency abalation scar was observed in all examined sections. Sustained ventricular arrhythmias requiring defibrillation occurred in 4 of 187 (2.1%) ungated applications, whereas no ventricular arrhythmias occurred during gated PFA applications (0 of 64 0%). Dark-blood late-gadolinium-enhanced sequences allowed for improved endocardial border detection as well as lesion boundaries compared with conventional bright-blood late-gadolinium-enhanced sequences. CONCLUSIONS: PFA penetrates infarct and iatrogenic scar successfully to create deep lesions. Gated delivery eliminates the occurrence of ventricular arrhythmias observed with ungated porcine PFA. Optimized magnetic resonance imaging sequences can be helpful in detecting lesion boundaries.