The aim of the study is to create a model of risk stratification to identify patients with increased risk of occurrence of composite (cardiovascular death or rehospitalization, arrhythmia recurrence) and secondary (inadequate device therapy, all-cause death or rehospitalization, intensification of atrial arrhythmia) endpoints after ablation of ES or sustained VT. Model will be based on additional measurements of N-terminal pro brain natriuretic peptide (NT-proBNP), Galectin-3, suppressor of tumorigenicity 2 (ST2), high sensitive troponin T (hs-TnT), high sensitive C-reactive protein (hs-CRP), iron deficiency to clinical-, electrocardiographic- and echocardiographic assessment.