A Feasibility Study on Prediction of an ICD Shock by ICD-derived Data

Inclusion Criteria: 1. Age ≧ 18 and ≦ 80 2. Patients have documented spontaneous and sustained ventricular arrhythmias in the last six months prior to the enrollment 3. Patients who are in sinus rhythm, have dual-chamber ICD or CRT-D implanted at least one month before enrollment 4. Patients who are in atrial fibrillation, have single-chamber ICD or CRT-D implanted at least one month before enrollment 5. Patients who are compliant to CareLink follow-up Exclusion Criteria: 1. Patients who are pregnant 2. Patients who are incapable of giving consent to the study 3. Patients who have a life-expectancy of less than 2 years