Stereotactic Arrhythmia Radioablation of Recurrent Ventricular Tachycardia in Structural Heart Disease

BACKGROUND Stereotactic arrhythmia radioablation (STAR) has been proposed to treat refractory ventricular tachycardia (VT) in patients with structural heart disease (SHD). OBJECTIVES The aim of the STAR-VT-2020 (Stereotactic Ablative Radiosurgery of Recurrent Ventricular Tachycardia in Structural Heart Disease) randomized trial was to compare the efficacy of STAR and catheter ablation (CA) after a failure of previous CA. METHODS Patients with VT recurrences were randomized at 2 centers (June 2020 to January 2024) to the STAR or CA group in a 1:1 fashion using a covariate-adaptive algorithm. In the STAR group, the arrhythmogenic substrate was irradiated by a single dose of 25 Gy delivered by a robotic system (CyberKnife). The planning target volume was delineated by coregistering the electroanatomical substrate map (CARTO 3) with the planning computed tomographic scan. In the CA group, CA was performed using substrate modification strategies. The primary endpoint was VT recurrence, while repeated CA was one of the secondary endpoints. RESULTS A total of 22 patients (68% men, mean age 67 ± 11 years, 27% with ischemic cardiomyopathy, mean left ventricular ejection fraction 31% ± 9%, 3.0 ± 1.3 previous CAs) were enrolled (11 in each group) and followed for 28 ± 17 months. The STAR patients exhibited a nonsignificantly higher risk for VT recurrence (HR: 2.5; 95% CI: 0.97-6.6) than those who underwent CA, and a significantly higher risk of repeated CA for VT (HR: 4.0; 95% CI: 1.2-13.8). Throughout the trial, 13 patients died, 3 underwent heart transplantation, and 3 received left ventricular assist devices, with no significant differences between the 2 groups. CONCLUSIONS The STAR-VT-2020 trial suggests a potential clinical benefit of repeated CA over STAR in patients with SHD, despite prior failed CA at specialized centers. Because of the small study cohort of highly selected patients and several methodological limitations, the results of the prematurely terminated trial should be considered exploratory and interpreted strictly as hypothesis generating. Larger trials with optimized design are warranted. (Stereotactic Ablative Radiosurgery of Recurrent Ventricular Tachycardia in Structural Heart Disease; NCT04612140).