Stereotactic Arrhythmia Radioablation (STAR): A Multidisciplinary Narrative Minireview of Preclinical Studies

The aim of this narrative review of the literature was to collect and analyze the results of the published preclinical studies on stereotactic arrhythmia radioablation (STAR) in the treatment of refractory cardiac arrhythmias. A literature search was conducted on PubMed using the following terms: ("stereotactic" OR "SBRT" OR "SABR" OR "radioablation" OR "radiosurgery") AND ("arrhythmia" OR "tachycardia"). Preclinical and pathological reports published in English without time limit, comprising studies of STAR in animal models and histological analyzes of explanted animal and human hearts were included. The analyzed studies confirm that doses lower than 25 Gy seem to produce sub-optimal therapeutic results whereas doses >35 Gy are less safe in terms of radiation-induced toxicity. However, long-term results (>1 year) are still missing and reporting outcomes based on low dose irradiation (≤15 Gy). Finally, STAR proved to be an effective therapy in the analyzed studies despite the irradiation of rather different cardiac targets. Therefore, additional studies are needed to: 1) compare the outcomes of STAR at doses of 25 Gy versus 30 Gy; 2) evaluate the long-term results (>1 year) in animal models irradiated at doses similar to those used in the clinic; 3) define the optimal target.