P1809Noninvasive cardiac radiosurgery: current clinical experience for treatment of refractory arrhythmias

Abstract

Introduction: Noninvasive ablation of cardiac arrhythmias using standard stereotactic radioablation devices has been reported, offering precise targeting of myocardial ablation sites non-invasively with 4-D imaging of anatomic targets using cardiac-specific planning and tracking software, with minimal radiation exposure outside of the treatment target. The procedure is painless and does not require anesthesia. A variety of radiosurgery platforms can be used. Objectives: We report our world-wide experience to date treating ventricular tachycardia (VT) and atrial fibrillation (AF) refractory to antiarrhythmic drugs and/or catheter ablation with noninvasive radioablation. Methods: Patients with VT refractory to antiarrhythmic drugs and catheter ablation, or ineligible for catheter ablation due to medical comorbidities, or drug-refractory symptomatic AF were enrolled. For patients with prior catheter ablation for VT, electroanatomic map(s) and CT, MRI, or PET were used to create an ablation target. In VT patients who had not undergone prior ablation, imaging and 12-lead ECG of VT localized an ablation target. In AF patients, CT was used to delineate atrial anatomy and targets. Planning software was used to design delivery of uniform, transmural ablative energy to the VT targets radioablation was performed with assistance from radiation oncologists and physicists. Patients were monitored with ICD interrogation, ambulatory monitoring, ECG, echo, chest X-ray, and clinical follow up. All patients were treated under approved IDE and IRB approvals. Results: Five patients (VT=4, AF=1) were enrolled. One VT patient was successfully planned, but did not undergo ablation due to inability to deploy a tracking fiducial. Single dose delivered was 25 Gy for all patients. Two patients were treated for scar-based VT, and the one was treated for idiopathic VT originating from the LV summit, inaccessible with endocardial/epicardial ablation, and the AF patient was treated with wide-area circumferential ablation encircling the pulmonary veins. All patients experienced a reduction in arrhythmia burden. One VT patient died (pneumonia), unrelated to treatment. Two patients have an arrhythmia-free survival of >12 months and continued to be followed. The AF patient developed recurrence of arrhythmia between 6-12 months after treatment, and elected to continue a medical rhythm control strategy. No complications were seen. Conclusion: For patients who have arrhythmia refractory to, …