Phase I/II Randomized Study of Stereotactic Ablative Radiotherapy (SABR) Versus Standard of Care for Refractory Structural Cardiac Arrhythmias (SABR-HEART)

Phase I: For the Phase I portion, there will be up to 15 patients treated with SABR and followed for 6 months post-treatment to ensure no significant acute grade 3 or 4 toxicity from SABR treatment. Efficacy as defined below will also be assessed. Following this Phase I lead-in, results will be presented to the FDA for review. Only upon favorable analysis by the FDA committee, and with written explicit permission, will the Phase II randomized portion ensue. This is to act as a safety and efficacy safeguard and has is addressed more thoroughly in the Statistical Analysis Plan of this protocol. Phase II: A 1:1 randomized Phase II portion with 25 patients in each arm assigned to SABR or current practice (standard of care; Figure 3). Standard of care is defined as nationally recognized appropriate next treatment strategies for medical and catheter-ablation refractory structural cardiac VT that is assessed and judged appropriate for the patient by his/her treating cardiologist. This includes repeat catheter ablation (intravascular and/or epicardial catheter ablation), placement of left-ventricular assist device (LVAD), heart transplant, or further medical management (e.g. antiarrhythmic drug modulation/continuation). Randomization will be performed through the Clinical Trial Conduct (CTC) website.