Efficacy and Safety of Strict Voltage-based Substrate Mapping and Radiofrequency Catheter Ablation in Electrical Storms—Review of Substrate-mapping Guided Ablation in Frequent Appropriate Shocks

Background: We investigated the efficacy and safety of strict voltage-based substrate mapping and radiofrequency catheter ablation (SV-substrate-map ablation) in patients with electrical storm. Methods and Results: SV-substrate-map ablation was performed in 15 patients suffering from multiple appropriate shocks (6.0 ± 3.8/day) from implantable cardioverter defibrillators (ICDs). Strict voltage criteria were defined as: non-arrhythmogenic areas, >0.6mV; low voltage areas, >0.1 to ≤0.6 mV; and scar, ≤0.1 mV. Using an electroanatomic mapping system, catheter ablation was performed at every possible arrhythmogenic region inside the low voltage areas. Further, we presented a review of the literature and investigated the published data on substrate-mapping guided ablation for electrical storm. After repeat endocardial ablation procedures in 4 patients and an epicardial approach in one, the targeted ventricular tachycardias (VTs) were successfully ablated, and the electrical storms were completely controlled in all. During a mean follow-up period of 801 ± 409 days, only one VT followed by an appropriate ICD shock was observed. No potential complications occurred during the procedure or follow-up. Our results were comparable or better than that of previous substrate-mapping guided ablation studies. Conclusion: SV-substrate-mapping ablation may be effective and safe for resolving serious clinical situations and prolonging the longevity of ICD devices in patients with electrical storms.