Stereotactic Radioablation for Ventricular Tachycardia in Patients Untreatable by Catheter Ablation: Evidence of Efficacy, Safety, and Impact on Coronary Arteries

Introduction: Ventricular tachycardia (VT) in patients with structural heart disease can be life-threatening and may persist despite antiarrhythmic therapy and catheter ablation. When standard treatments are ineffective or contraindicated, stereotactic arrhythmia radioablation (STAR) has emerged as a non-invasive salvage option. Methods: This prospective, single-center study included 19 patients with structural heart disease and recurrent VT unresponsive to conventional therapy and who were ineligible for ablation. Patients were selected by a multidisciplinary team and underwent cardiac CT and electroanatomic mapping for substrate characterization. STAR was delivered in a single 25Gy fraction using volumetric modulated arc therapy. Primary endpoints included safety (adverse events within 12 months) and efficacy (reduction in VT burden, assessed by ICD-recorded anti-tachycardia pacing [ATP] and shocks). Results: During a median follow-up of 14 months [IQR 9-15], STAR was associated with a significant reduction in ICD therapies, with an average decrease of 81%. Mean ATP interventions/month dropped from 4.5±6.5 to 0.8±2.3 (p=0.029), and total ICD therapies/month decreased from 4.8±7.0 to 0.9±2.5 (p=0.032). Mild pulmonary injury and pericardial effusion occurred in 22.2% of patients. Most cases were asymptomatic; one patient (5.5%) required non-urgent pericardiocentesis. No significant changes in left ventricular function, valvular status, or coronary artery disease progression (assessed by CAD-RADS and PCAT analysis) were observed. One-year mortality was 33.3%; no deaths were directly attributable to STAR. Conclusion: STAR shows promise as a safe, noninvasive option for patients with refractory VT and advanced cardiomyopathy. Larger multicenter studies are needed to confirm long-term outcomes and better define its clinical role.