Impact of cardiac muscle metabolism and calcium load on lesion formation by pulsed-field electroporation in pig ventricles
A Gil Ramirez, J Norup Hertel, T Jespersen, D Linz, S Dalgas Nissen, J HansenAbstract
Background
Catheter pulsed field ablation (PFA) is used increasingly to create cardiac muscle specific lesions to treat arrhythmias. While most current research has focused on optimizing catheter design and energy delivery parameters, less attention has been given to tissue determinants of lesion formation. Evidence suggests that calcium overload and changes in metabolism may enhance PFA-induced cellular injury and lesion development; however, this has not yet been systematically studied.
Purpose
To assess whether increased oxidative metabolism or increased calcium load to tissue enhances PFA lesion formation in the ventricle.
Methods
Twelve female Landrace pigs (~50 kg) received focal left ventricular (LV) PFA lesions using the Cardiofocus CENTAURI PFA-generator (25A, 10 pulse-trains) via a contact-force ablation catheter (ThermoCool SmartTouch Catheter, Biosense Webster). The PFA was performed during calcium infusion (n=3), during isoprenaline and rapid pacing (n=5); or without intervention (n=4). After 1.5 hours, the animals were euthanised, and lesions (depth, width, and transmurality) were assessed using 1% TTC (2,3,5-triphenyltetrazolium chloride).
Results
71 monopolar biphasic PFA lesions were delivered in the LV (5-7 lesions per pig, Figure 1, left). TTC staining showed ellipsoid lesions with a haemorrhagic core surrounded by a sharp demarcated pale non-viable zone (Figure 1, mid). Mean lesion depth was: 7.3, 8.2, and 7.8mm; width: 10.2, 11.4, and 11.4mm; volume: 212.4, 288.7, and 287.1mm3, and transmurality: 53.7%, 57.8%, and 56.2% in the calcium, isoprenaline, and control, respectively (Figure 1, right). None of the interventions changed the size of the lesions significantly (p≥0.5).
Conclusion
Application of focal PFA produced reproducible ventricular lesions that were deep relative to wall thickness and within the upper range reported for ventricular focal PFA lesions. The lesions were not modified by augmented metabolic stress or increased calcium delivery to the tissue