Abstract 4367769: Successful Mapping and Ablation of Incessant Ventricular Fibrillation on Mechanical Circulatory Support.

Background/Introduction: Ventricular fibrillation (VF) storm represents a life-threatening emergency with high mortality. When VF becomes incessant and refractory to antiarrhythmic therapy, catheter ablation is not usually considered. We present a case of successful VF ablation in a patient with incessant, refractory VF requiring mechanical circulatory support. Objective: To report a successful catheter ablation of incessant VF in a patient with ischemic cardiomyopathy on mechanical circulatory support. Methods: N/A Results: A 77-year-old male with ischemic cardiomyopathy (LVEF 35%), multivessel CAD status post PCI, severe aortic stenosis status post TAVR, and prior out-of-hospital cardiac arrest with ICD implantation, presented with VF storm despite amiodarone and lidocaine infusions. Despite deep sedation, intubation, stellate ganglion block, and maximal antiarrhythmic therapy, he developed incessant VF with hemodynamic collapse, requiring emergent VA ECMO. Post-ECMO, VF became incessant over three consecutive days, and unresponsive to defibrillation. VF catheter ablation was performed while on VA ECMO support. Since the patient could not be defibrillated successfully, we decided to map the left ventricle during ongoing VF. We targeted the posterior and mid fascicular area based on high frequency fascicular signals on the border of a basal septal scar using 40-watt lesions for 30 seconds (Images 1 and 2). Following septal “defasciculation”, a single defibrillation at 360 joules successfully converted the patient to atrial-paced, ventricular-sensed rhythm. The QRS duration increased from 108 ms to 156 ms, which recovered the next day. For the first time in three days, the patient remained VF-free. Post-ablation, there was immediate hemodynamic improvement with reduced vasopressor requirements. The patient was decannulated after 48 hours and the antiarrhythmic therapy was rapidly de-escalated. He was discharged home on low dose amiodarone and in normal sinus rhythm. Conclusion: This case demonstrates that targeted catheter ablation can successfully terminate incessant VF refractory to medical and adrenergic suppressive therapies by defasciculation of the septal scar and targeting very high frequency fascicular signals. VA ECMO provided essential circulatory support enabling precise ablation during VF. This potentially expands the role of catheter ablation as a life-saving intervention for incessant refractory VF.