Stereotactic body radiotherapy for ventricular tachycardia (cardiac radiosurgery)

Abstract

Single-session cardiac stereotactic body radiotherapy, called cardiac radiosurgery (CRS) or radioablation (RA), may offer apotential treatment option for patients with refractory ventricular tachycardia (VT) and electrical storm who are otherwise ineligible for catheter ablation. However, there is only limited clinical experience. We now present the first-in-patient treatment using (CRS/RA) for VT in Germany. A78-year-old male patient with dilated cardiomyopathy and significantly reduced ejection fraction (15%) presented with monomorphic VT refractory to poly-anti-arrhythmic medication and causing multiple implantable cardioverter-defibrillator (ICD) interventions over the course of several weeks, necessitating prolonged treatment on an intensive care unit. Ultra-high-resolution electroanatomical voltage mapping (EVM) revealed are-entry circuit in the cardiac septum inaccessible for catheter ablation. Based on the EVM, CRS/RA with asingle session dose of 25 Gy (83% isodose) was delivered to the VT substrate (8.1 cc) using ac-arm-based high-precision linear accelerator on November 30, 2018. CRS/RA was performed without incident and dysfunction of the ICD was not observed. Following the procedure, asignificant reduction in monomorphic VT from 5.0to 1.6episodes per week and of ICD shock interventions by 81.2% was observed. Besides periprocedural nausea with asingle episode of vomiting, no treatment-associated side effects were noted. Unfortunately, the patient died 57days after CRS/RA due to sepsis-associated cardiac circulatory failure after Clostridium difficile-associated colitis developed during rehabilitation. Histopathologic examination of the heart as part of aclinical autopsy revealed diffuse fibrosis on most sections of the heart without apparent differences between the target area and the posterior cardiac wall serving as acontrol. CRS/RA appears to be apossible treatment option for otherwise untreatable patients suffering from refractory VT and electrical storm. Arelevant reduction in VT incidence and ICD interventions was observed, although long-term outcome and consequences of CRS/RA remain unclear. Clinical trials are strongly warranted and have been initiated.