'Cardiac Radioablation – a Systematic Review′

Abstract Failure of drugs and catheter ablations for the treatment of ventricular arrhythmias is still extremely relevant. Recently, stereotactic body radiotherapy has been introduced to treat therapy refractory patients. In this systematic review (PROSPERO, CRD42019133212), we aimed to summarize electrophysiological and histopathological effects of radioablation in animals, patients, and extracted and perfused hearts. A systematic search was performed in MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Google Scholar, ClinicalTrials.gov and WHO-ICTRP, from inception to September 2019. Identified records were independently screened for eligibility by two reviewers. Risk of bias and methodological quality was assessed using the SYRCLE, the ROBINS-1 or Murad tool and tailored to the different study designs. We included 13 preclinical and 10 clinical publications. Large heterogeneity in study designs prompted a narrative synthesis approach. Baseline, (pre-)procedural details, outcome, target-tissue analyses and safety data were extracted and summarized. In animal studies evaluating electrophysiological parameters, radioablation induced a reduction in voltage/potential amplitude or bidirectional block in target areas in 93.2% of animals. AV-block (1st-3rd degree) was induced in 78.3% of animals and in studies evaluating ventricular arrhythmia inducibility, 75% reduction was achieved. In patients, predominantly ventricular tachycardias were targeted with >85% reduction in arrhythmia episodes during follow-up with an encouraging short-term safety profile. Preclinical and clinical evidence on efficacy and safety of radioablation is limited in both quantity and quality. The results of radioablation for therapy refractory patients with ventricular tachycardia are promising but further research is needed.