Stereotactic radiosurgery for ablation of ventricular tachycardia in the setting of electrical storm

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Stereotactic body radiotherapy (SBRT) has been reported as a safe and efficient therapy to treat refractory VT despite optimal medical treatment and/or catheter ablation (CA). However data in the setting of ES are lacking. Objectives The aim of this study was to assess the clinical outcomes associated with SBRT in the setting of ES. Methods This retrospective study included patients who underwent SBRT in the setting of ES from March 2019 to March 2021 in one tertiary center (CHU Lille). Target volume was delineated according to a predefined workflow. The efficacy was assessed with the following endpoints: sustained VT recurrence, VT reduced with ATP or ICD shock. Results 17 patients underwent SBRT to treat refractory VT in the setting of ES (Mean age: 67±12.8, 59% presenting ischemic heart disease, mean LVEF: 33.7± 9.7%). After a median follow-up of 7 [5; 16] months, a reduction in VT burden was observed in all patients after a 6-week blanking period. 6 patients presented an increase of the VT burden from week 2 to week 6 following SBRT despite an initial reduction of VT burden. No patient experienced ICD shocks beyond 6 weeks. Conclusion SBRT is efficient in treating recurrent VT in the setting of ES with failure and/or contraindication to CA. One third of patient present a transient increase in VT burden during a 6 weeks blanking period. Therefore, VT tolerance should be integrated as part of an action plan defined upstream to SBRT for each patient.