Background <p>Stereotactic arrhythmia radioablation (STAR) is an emerging treatment for refractory or recurrent arrhythmias. Compared with conventional stereotactic body radiotherapy (SBRT), STAR involves greater complexity in target delineation, motion management, and organs at risk (OARs) protection, yet it lacks established consensus clinical guidelines, and workflow-specific risk analyses remain limited.</p> Objective <p>To develop a C-arm linear accelerator (LINAC)-based STAR workflow and perform a failure modes and effects analysis (FMEA) with fault tree analysis (FTA), supplemented by an exploratory segment-based anatomical proximity analysis.</p> Methods <p>A multidisciplinary team constructed a process map for C-arm LINAC-based STAR and identified potential failure modes across the workflow. Risks were scored using occurrence, severity, and detectability to calculate risk priority numbers (RPNs), and FTA was used to analyze causal pathways. In a predefined exploratory imaging subgroup of eight patients with ventricular tachycardia and simulation-acquired coronary computed tomography angiography (CCTA), we divided the left ventricle according to the 17-segment model and measured the minimum distances from each segment to adjacent OARs as an anatomical surrogate of exposure likelihood.</p> Results <p>Seventy-nine failure modes were identified, of which 17 were classified as high risk. The highest-risk failure modes were concentrated in target delineation and motion-related steps, including inaccurate multimodal image registration (RPN 432), improper motion evaluation/management (RPN 336), and diagnostic error of arrhythmia substrate definition (RPN 320). In the exploratory imaging subgroup (<i>n</i> = 8), segmental spatial patterns were moderately consistent across patients, with most standard deviations of minimum distance below 2.0&#xa0;cm, although variability remained for several segment-OAR relationships. Segments 4, 5, and 10 were each located within 2&#xa0;cm of both the stomach and esophagus, indicating relatively higher anatomical proximity-related risk.</p> Conclusion <p>In this FMEA of C-arm LINAC-based STAR, the principal high-risk workflow steps were concentrated in substrate definition, image registration, and motion management. The segment-based analysis provides an exploratory anatomical risk-mapping framework for OAR awareness. Further multicenter studies are needed to refine workflow risk prioritization and evaluate the clinical relevance of the segment-based anatomical findings.</p> Clinical trial number <p>Not applicable.</p>