Predictive Risk Stratification Through T Variability in ICD Patients Without Pacing Indications

Inclusion Criteria: Patient has been prescribed the implantation of an SORIN GROUP OvatioTM DR 6550 / VR 6250 system according to relevant currently-approved guidelines * CHF since \> 3 months and * LVEF \< 35% and * NYHA class II or III OR * Prior Myocardial infarction since more than 4 weeks and * LVEF \< 30% Exclusion Criteria: * Documented spontaneous sustained ventricular tachycardia * Prior implant of any device for ventricular cardiac pacing * Existing indication for permanent ventricular pacing * Myocardial infarction within 4 weeks prior to enrollment * Arrhythmogenic RV-Dysplasia * Brugada syndrome * Long QT syndrome * Performed within 3 months prior to enrollment or scheduled (within 3 months) cardiac revascularization (interventional or surgical) * Any indication for CRT accordingly to the relevant currently-approved ACC/AHA1 or ESC35 guidelines for the implantation of a CRT system. * Excisting or planned administration of amiodarone - initiation of amiodarone therapy during the run of the study will lead to immediate exclusion of the patient * Permanent chronic atrial fibrillation / flutter * Patient is unable to attend the scheduled follow-up visits at the participating centre * Patient is already included in another ongoing clinical study * Patient is unable to understand the objectives of the study * Patient refuses to cooperate * Patient is unable or refuses to provide informed consent * Patient is minor (less than 18-year old) * Patient has life expectancy of less than 1 year * Patient is pregnant.