ESTRO 2024 - Abstract Book

S1912

Clinical - Mixed sites, palliation

ESTRO 2024

1346

Digital Poster

Impact of cardiac SABR on ventricular tachycardia episodes: single institution experience.

Sophie T Lynch 1 , John Whitaker 2 , George Ntentas 3 , Marina Khan 4 , Rebecca Preston 5 , Aldo Rinaldi 2 , Shahreen Ahmad 1

1 Guy's and St.Thomas' NHS Trust, Clinical Oncology, London, United Kingdom. 2 Guy's and St.Thomas' NHS Trust, Cardiology, London, United Kingdom. 3 Guy's and St.Thomas' NHS Trust, Medical Physics, London, United Kingdom. 4 Guy's and St.Thomas' NHS Trust, Radiotherapy, London, United Kingdom. 5 Guy's and St.Thomas' NHS Trust, Radiology, London, United Kingdom

Purpose/Objective:

Cardiac stereotactic radiotherapy (cSABR), also known as stereotactic arrhythmia ablation (STAR) or cardiac radiosurgery, is an emerging technique for treating refractory cardiac arrhythmias, primarily ventricular tachycardia (VT). cSABR is considered following failure of anti-arrhythmic agents and trans-catheter ablation when indicated. Patients typically have an implantable cardioverter defibrillator device (ICD) which can deliver anti-tachycardia pacing (ATP) and defibrillator ‘shocks’ in order to terminate episodes of VT. We report our experience of the impact of cSABR treatment on ventricular tachycardia frequency in the six months before and after cSABR treatment for the initial cohort of patients treated at our institution.

Material/Methods:

Suitable patients were identified by cardiologists at our institution. Following discussion at the local cardiac electrophysiology multi-disciplinary team (MDT) meeting they were referred to clinical oncology and subsequently discussed at the UK cSABR monthly MDT meeting. Delineation of the target volume was defined on a 4D-CT collaboratively between a clinical oncologist, cardiologist and cardiac radiologist. A combination of substrate information acquired from cross-sectional cardiac imaging: contrast enhanced cardiac computed tomographic (CCT) imaging with late iodine enhancement (LIE) and, in some, cases cardiovascular magnetic resonance (CMR) imaging with late-gadolinium enhancement (LGE) and electrophysiologic information including 12-lead ECG of clinical tachycardia, electro-anatomic mapping data where available and body-surface mapping of tachycardia induced during non-invasive programmed stimulation (NIPS) was used. Patients were treated on a Varian TrueBeam STx Linac with a six degrees of freedom couch (6DoF), using Varian’s respiratory gating (RPM) with abdominal compression as motion management and AlignRT for surface guidance (SGRT). A prospective registry of patients treated with cSABR at our institution is held. Data downloaded from device interrogations was used to assess arrhythmia burden and a comparison made between the 6 months prior to and the 6 months following cSABR treatment. Primary outcomes were: number of appropriate shocks for VT, total time in VT and number of appropriate ATP therapies delivered for VT.

Results: