B-PO03-206 TERMINATION OF VENTRICULAR FIBRILLATION DURING CATHETER ABLATION

Abstract

Catheter ablation (CA) targeting Purkinje triggers is an established technique for treating ventricular fibrillation (VF). However, the mechanism of human VF maintenance is not well understood. While 2 previous cases of spontaneous termination of VF after CA have been reported, none have occurred during radiofrequency (RF) application. N/A N/A A 50 year-old man presented to an outside hospital with a STEMI and underwent PCI to the RCA. He developed VF refractory to IV amiodarone, lidocaine and over 10 defibrillation attempts. He was placed on full circulatory support and transferred to our institution. Procainamide and then PO quinidine were also ineffective with persistent VF storm. The VF appeared to be initiated by a PVC with indeterminate V1 morphology with superior axis and dominant S wave, suggestive of moderator band (MB) or left posterior fascicle PVC (Panel A). He was brought to the EP lab, where the same PVC initiated VF, requiring defibrillation. An ablation catheter was positioned at the MB (Panels B, C). 85 s into an episode of VF, RF energy was delivered and in 3.8 s terminated VF to monomorphic VT (MMVT) (Panel D). The MMVT was then mapped to an exit site lateral to the posteromedial papillary muscle. The signal was 65 ms pre-QRS at this site and ablation terminated VT to SR. VF and VT did not recur and circulatory support was weaned. To our knowledge, this case is the first reporting direct termination of VF during delivery of RF energy. Though it is well known that abnormal Purkinje potentials and resultant PVCs may serve as initiators of VF, this case presents direct evidence that the triggering focus may in fact be critical to VF maintenance.