Although the beneficial effect of ICD treatment has been proven in selected patients, the population assessed in large clinical trials does not reflect the population with ICDs in the real world. The aim of the current thesis is to give better insight in these patients at risk for lifethreatening arrhythmias by studying a large population of patients treated with an ICD, outside the setting of a clinical trial. In part I, the actual need for defibrillator backup during long-term follow-up is evaluated. Chapter 2 describes differences in mortality and the occurrence of ventricular arrhythmia between patients receiving an ICD as primary vs. secondary prevention of SCD. The actual need for device replacement after an event-free first battery service-life is studied in Chapter 3. In part II, an attempt is made to improve risk stratification by evaluating currently available parameters and the additive value of novel parameters. In Chapter 4 all classic baseline variables are combined to construct a clinically applicable mortality risk score in primary prevention ICD recipients with ischemic heart disease. Chapter 5 demonstrates the importance of atrial fibrillation in patients with ICD or CRT-D. Chapter 6 shows that usage of a risk model can predict the risk of non-benefit (death, prior to first ventricular arrhythmia) which might have important clinical consequences. In Chapter 7 the spatial QRS-T angle is evaluated in the prediction of ventricular arrhythmia. Chapter 8 demonstrates the risk of lead failure in smalldiameter defibrillation leads compared with a benchmark cohort.UBL - phd migration 201
