Stereotactic Arrhythmia Radioablation (STAR) for refractory ventricular tachycardia- the initial Australian experience.

Abstract

Background: Stereotactic arrhythmia radioablation (STAR) is a novel, noninvasive technique for the management of refractory ventricular tachycardia (VT).

Objectives: This retrospective study aimed to assess the feasibility, efficacy, and safety of STAR in an Australian cohort.

Methods: From February 2020 to August 2023, 12 patients with drug-refractory VT who had either failed catheter ablation or were unsuitable, were treated with stereotactic ablative radiotherapy (STAR) in two Australian centres. A combination of electrocardiograms, multi-modality imaging and non-invasive/invasive mapping data was used to target the presumed ventricular tachycardia substrate. All treatments (25 Gy in one fraction) were delivered without anaesthesia. Efficacy endpoints were defined as the number of VT episodes, anti-tachycardia pacing (ATP), VT storms and shocks six months before and after treatment (6-week blanking period). Mortality and adverse event data were collected over 12-month follow-up (FU).

Results: In the nine patients who survived the blanking period, a significant reduction (64.5%, P = 0.011) in VT burden and VT storm (71.7%, P = 0.027) was observed over a 6-month FU. However, 66.7% (6/9) of these patients experienced VT recurrence. 3/6 patients with recurrence with ECGs available for review had the same VT morphology as pre-STAR. Over a 12-month FU, five patients died, and three adverse events were recorded (undersensing of defibrillator lead, increased rate of reflux and radiation pneumonitis).

Conclusions: This paper summarises the initial Australian experience treating refractory VT with STAR. It demonstrates that STAR can significantly decrease the VT and VT storm burden over a 6-month FU with an acceptable acute side-effects profile, albeit with a high VT recurrence rate.