PO-05-093 STEREOTACTIC RADIOTHERAPY FOR REFRACTORY VENTRICULAR TACHYCARDIA LEADS TO PROLONGATION OF ARRHYTHMIA CYCLE LENGTH

Stereotactic body radiotherapy (SBRT) is a novel treatment for otherwise resistant ventricular tachycardias (VTs). Different mechanisms of SBRT VT suppression were proposed that include radiation-induced fibrosis but also SBRT-triggered increase in myocardial conduction velocities without significant fibrotic changes. The study compared the morphologies and cycle lengths (CLs) inducible VTs during re-do catheter ablation after with before SBRT. We investigated patients underwent (a single session 25 Gy) refractory subsequent electrophysiology / reablation recurrences VTs. All analysed concerning morphology CL. A total 9 (2 women, aged 60 ± 13 years) included. Two had ischemic heart disease, six nonischemic cardiomyopathy, one cardiac fibroma. on chronic amiodarone treatment. mean ejection fraction left ventricle was 35 12%. planning target volume 39 21 ml. Electrophysiology study/reablation performed at interval 8 months (interquartile range: 2-10months) 23 27 distinct SBRT, respectively. Twelve pairs identified identical CL these decreased from 399 98 ms to 472 74 (P = 0.01) Overall, 15/27 (56%) all induced originated irradiated region. Recurrent commonly origin In pairwise comparison, has prolonged This suggests results rather than an velocity.