Case series on stereotactic body radiation therapy in non-ischemic cardiomyopathy patients with recurrent ventricular tachycardia

Introduction: The efficacy of stereotactic body radiation therapy (SBRT) as an alternative treatment for recurrent ventricular tachycardia (VT) is still unclear. This study aimed to report the outcome of SBRT in VT patients with nonischemic cardiomyopathy (NICM). Methods: The determination of the target substrate for radiation was based on the combination of CMR results and electroanatomical mapping merged with the real-time CT scan image. Radiation therapy was performed by Flattening-filter-free (Truebeam) system, and afterward, patients were followed up for 13.5 ± 2.8 months. We analyzed the outcome of death, incidence of recurrent VT, ICD shocks, anti-tachycardia pacing (ATP) sequences, and possible irradiation side-effects. Results: A total of three cases of NICM patients with anteroseptal scar detected by CMR. SBRT was successfully performed in all patients. During the follow-up, we found that VT recurrences occurred in all patients. In one patient, it happened during a 6-week blanking period, while the others happened afterward. Re-hospitalization due to VT only appeared in one patient. Through ICD interrogation, we found that all patients have reduced VT burden and ATP therapies. All of the patients died during the follow-up period. Radiotherapy-related adverse events did not occur in all patients. Conclusions: SBRT therapy reduces the number of VT burden and ATP sequence therapy in NICM patients with VT, which had a failed previous catheter ablation. However, the efficacy and safety aspects, especially in NICM cases, remained unclear.