Stereotactic Arrhythmia Radiation Therapy Versus Repeat Catheter Ablation for Refractory Ventricular Tachycardia: 3-Year Safety and Efficacy Outcomes

Abstract

Purpose: Stereotactic arrhythmia radiation therapy (STAR) is a noninvasive treatment alternative to repeat catheter ablation (CA) for refractory ventricular tachycardia (VT). However, no studies have directly compared the 2 modalities. This study reports 3-year safety and efficacy outcomes for STAR versus CA in patients with refractory VT at a high-volume center. Methods and Materials: We conducted a retrospective cohort analysis of all patients with recurrent VT who failed medical management with antiarrhythmic medications and failed at least 1 prior CA (or were deemed medically unfit for CA) who were then treated with either STAR or repeat CA between 2015 and 2018 at a single institution. Patients treated with STAR who did not receive prior CA were evaluated on a case-by-case basis and deemed by the treating electrophysiologist to be too high risk to undergo repeat CA (“medically unfit for CA”). Patients were evaluated for serious adverse events (SAEs); freedom from death, shock, or storm (FFDSS); and overall survival. Survival analyses were performed via the Kaplan-Meier method and compared by the log-rank test. Results: Forty-three patients were included: 22 received STAR and 21 received repeat CA. Baseline characteristics were similar; however, generally patients treated with STAR were older (median, 64.5 vs 59 years), had “High Risk” international ventricular tachycardia (I-VT) scores (64% vs 52%), and had higher PAINESD scores (median, 18.5 vs 17). Median follow-up was 3 years. More patients treated with CA (N = 8, 38%) developed 1-year treatment-related SAEs compared with STAR (N = 2, 9%). Median time to any SAE was shorter for patients treated with CA compared with STAR (6 days vs 10 months), and most early CA deaths occurred immediately after SAE. Twelve patients died within 3 years of STAR; 75% (N = 9) were unrelated to VT, and none were from treatment-related SAE. There was no statistically significant difference in FFDSS between patients treated by STAR versus CA (6.9 vs 2.9 months; P = .88). FFDSS for STAR versus CA was 32% versus 27% at 1-year, 27% for both at 2-years, and 18% versus 21% at 3-years. There was no statistically significant difference in overall survival between patients treated with STAR versus CA (28.2 vs 12.2 months; P = .91). Conclusions: At 3-year follow-up, STAR offers comparable VT control with fewer SAEs and longer time to toxicity, supporting its possible role as a noninvasive alternative to repeat CA. These findings warrant further prospective study.