Noninvasive Electrocardiographic Imaging for Individuals at Risk for Apparently Idiopathic Ventricular Fibrillation.

This study aims to evaluate the electrophysiological properties of the heart conduction system in patients with unexplained polymorphic ventricular tachycardia (VT) and/or ventricular fibrillation (VF), in patients with specific genetic mutations regarding sudden cardiac death or sudden cardiac arrest, in their family members and in a control cohort. The electrophysiological properties will be measured with the relatively new technique ECG-Imaging (ECGI). Also a National Dutch registry for patients with unexplained polymorphic VT and/or VF and their family members will be created. By combining the data from the registry and the results of ECGI, The investigators hope to identity risk markers for patients at higher risk for apparently idiopathic ventricular fibrillation, and use these for an adapted flow chart for the 'general'population of patients at risk for unexplained polymorphic VT and/or VF. The investigators aim to be able to identify patients before the first arrhythmic event, and aim for better treatment strategies in the future.