Better Mechanistic Understanding of and Risk Stratification for Ventricular Tachyarrhythmias Through ECGI

Inclusion Criteria: In order to be eligible to participate in this study, a subject must be ≥ 18 years old, have either a history of VTAs or be at risk of VTAs and have one of the following diagnoses: * Ischemic cardiomyopathy * Non-ischemic cardiomyopathy * Non-structural heart disease * Congenital heart disease (with a limitation to CCTGA and situs inversus) Or: a subject must be ≥ 18 years old and have a structurally normal heart with a clinical indication for a cardiac CT. Exclusion Criteria: A potential subject who meets any of the following criteria will be excluded from participation in this study: * A known strong reaction against electrode attachment or contrast agent. * Any serious medical condition, which in the opinion of the investigator, may adversely affect the safety and/or effectiveness of the participant or the study. * Pregnancy, nursing or planning to be pregnant. * The subject has an estimated glomerular filtration rate (eGFR) of \<30mL/min/1.73m2, using the MDRD calculation 14. * Being unable to give informed consent.