PO-01-026 STEREOTACTIC CARDIAC RADIOTHERAPY FOR RECURRENT VENTRICULAR TACHYCARDIA IN PRESENCE OF WIRELESS LEFT VENTRICULAR ENDOCARDIAL STIMULATION SYSTEM

Abstract

Cardiac stereotactic body radiotherapy (SBRT) is a novel therapy for refractory ventricular tachycardia (VT). However, there remain knowledge gaps due to limited experience. The wireless stimulation endocardial cardiac resynchronization therapy (WiSE CRT) is a promising method of left ventricular (LV) resynchronization using a receiver electrode implanted in LV and a transmitter implanted in the intercostal space that is connected to a subcutaneous battery. The safety of cardiac SBRT in the presence of WiSE CRT has not been reported. We present a case of successful cardiac SBRT for recurrent VT from the LV apex delivered safely in a patient with WiSE CRT. N/A An 83-year-old man had a history of ischemic cardiomyopathy with LV apical infarct, LV ejection fraction 20%, NYHA Class III, underlying left bundle branch block status post CRT-D placement, severe coronary artery disease, paroxysmal atrial fibrillation, chronic kidney disease stage III, hyperlipidemia and orthostatic hypotension. He had initially presented with appropriate defibrillator discharges due to paroxysmal VT. He underwent catheter ablation of VT originating from the LV apex. The procedure was complicated by pericardial effusion requiring emergent pericardiocentesis. He was discharged on amiodarone but this had to be discontinued due to adverse effects. He had recurrence of VT and defibrillator shock and mexiletine was started. He started experiencing worsening heart failure symptoms. CRT-D interrogation revealed recurrent episodes of VT terminated by antitachycardia pacing and LV lead malfunction with high impedance and elevated capture threshold with loss of LV pacing. He underwent WiSE CRT system implant and the transvenous LV lead was turned off. Subsequently he had multiple admissions for VT storm requiring device therapies despite antiarrhythmic medication changes including sotalol and mexiletine. Therefore, he underwent cardiac SBRT targeting the LV apical substrate with 25 Gy dose delivered in a single fraction. SBRT treatment plan was created by contouring the components of the Wise CRT system and limiting dose to them <10 Gy (Figure). He has been weaned off antiarrhythmic drugs and has had no recurrent VT for 2.5 months since SBRT. Wise CRT function and battery status remained stable with no detrimental effects based on device interrogation till 2.5 months post SBRT. With careful treatment planning, cardiac SBRT can be delivered safely in the presence of WiSE CRT.