To Evaluate the Delivery Timing Safety and Efficacy of AntiTachycardia Pacing (BIO|ATP)

Inclusion Criteria: * Patient has an indication for ICD according to the The Japanese Circulation Society (JCS )/ Japanese Heart Rhythm Society (JHRS) 2021 Guideline Focused Update on Non-Pharmacotherapy of Cardiac Arrhythmias * Patient is either planned for de novo ICD implantation or is already implanted with an investigational ICD for 10 days or less. * Patient can be treated with ATP therapy for both VT and VF zone * Patient is willing and able to use the CardioMessenger and accepts the Home Monitoring concept * Patient is willing to visit the hospital in accordance with physician's instruction * Patient is able to understand the nature of the study and to provide written informed consent Exclusion Criteria: * Patient planned for implantation with or already implanted with Cardiac Resynchronization Therapy Defibrillator (CRT-D) device * A patient who is confirmed to have received ICD therapy * A patient who is diagnosed as Idiopathic VF (e.g. Brugada syndrome, Long QT Syndrome, other IVF) * Age \< 18 years * A patient who has impaired mental status * Life expectancy less than 18 months * Participation in another interventional clinical investigation * Pregnant or breastfeeding