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

Abstract

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.

Stereotactic Radiotherapy in the Management of Ventricular Tachycardias

“…In 2021, several other groups presented their first experience with SBRT for VTs in small series of patients. [20][21][22][23] The results were similar to the initial studies, with relatively high mortality, reflecting the severity of heart disease in this high-risk population. Other studies showed less optimistic data.…”

Safety and Efficacy of Stereotactic Arrhythmia Radioablation for the Treatment of Ventricular Tachycardia: A Systematic Review

“…In 6 studies, there was a significant reduction (>80%) of VT burden at follow-up. In other studies reduction of VT burden at follow up ranges between 30 and 70% ( 9 , 10 , 16 ), or there was no reduction in one case ( 13 ).…”

“…Three retrospective case series (7)(8)(9), two retrospective (10,11), and five prospective studies (12)(13)(14)(15)(16) were included in our systematic review. The baseline characteristics of the patients included in the analysis are reported in Table 1.…”

Case report: Stereotactic body radiation therapy with 12 Gy for silencing refractory ventricular tachycardia

“…Cardiac SBRT with 25 Gy in one fraction is a new and innovative treatment for patients with refractory VT (Table 2). To date, eight case reports (17-24) and 11 case series (11,12,(25)(26)(27)(28)(29)(30)(31)(32) have been published. Ninety-one patients were treated with a radiation dose of 25 Gy, and one patient was treated with 24 Gy.…”

“…Endothelial vacuolization and disruption of gap junctions on electron microscopy specimens is noted after SBRT as relatively acute effects that occur well before cellular DNA damage–related apoptosis and fibrosis begin ( 27 ). Additionally, severe architectural disruption, inflammatory cell infiltration, fibrin deposition and necrosis in myocardial tissue caused by high-dose irradiation in swine have been reported ( 22 , 30 , 31 ). Notably, irradiation with 16 Gy to the mouse heart induced mitochondrial damage and metabolic alterations of the cardiac tissue and led to structural remodeling, functional injury and fibrotic alterations ( 36 ).…”