Abstract Body (Do not enter title and authors here): Background: Patients with left ventricular assist devices (LVADs) may develop ventricular tachycardia (VT) refractory to conventional antiarrhythmic strategies. Catheter ablation is associated with increased procedural risks in this population and may be less effective, especially when critical substrate is epicardial or near the LVAD cannula. Cardiac stereotactic body radiotherapy (SBRT) has emerged as a promising therapy for patients with VT refractory to antiarrhythmic drugs (AADs) and catheter ablation. However, clinical data on SBRT in patients with LVADs remain limited.

Objective: To evaluate the safety and efficacy of cardiac SBRT in managing refractory VT in patients with durable LVAD support.

Methods: We conducted a retrospective review of all patients with existing LVADs who underwent SBRT (25 Gy) for drug- and ablation-refractory VT at our institution. All patients had previously failed conventional therapies. Clinical outcomes, including VT recurrence, implantable cardioverter defibrillator (ICD) therapies, ventricular function, complications, and survival, were assessed over a follow-up period ranging from 3 to 28 months.

Results: Four patients met inclusion criteria (see Table). Three experienced VT recurrence: one within the first month and two within two months post-SBRT. One of these recurrences resulted in an ICD shock. One patient has remained arrhythmia-free for 14 months post-treatment. Importantly, no patients experienced LVAD-related complications attributable to SBRT. Post-treatment echocardiographic assessment revealed no significant changes in left or right ventricular function. Three patients died during follow-up at 3, 17, and 22 months. Only one death was directly attributed to refractory VT; the remaining two were due to hypoxic respiratory failure and septic shock.

Conclusion:
In this small series, cardiac SBRT appeared safe and potentially beneficial for patients with LVADs and refractory VT. Although most patients experienced recurrent VT, SBRT may delay recurrence in selected high-risk individuals. One patient achieved sustained arrhythmia suppression. These findings support further investigation of SBRT as a non-invasive adjunctive therapy in this challenging population.