The purpose of this study is to evaluate the strategy of implanting an ICD with or without EPS before, during and after ICD-implantation in a randomised controlled trial, using a combined endpoint of major ICD-related adverse events as the primary outcome measure.

Usually, EPS before and during ICD-implantation is performed to allow risk stratification, to test serial antiarrhythmic drugs, to find suitable ablation sites in patients with hemo-dynamically stable monomorphic VTs, to exclude supraventricular tachycardias as a cause of cardiac arrest and to help programming detection rate and enhancement criteria in the ICD. However, routine EPS preceeding ICD-implantation exposes the patient to some risk and the health care system to considerable costs. So the question has been raised, whether such testing is still necessary and costseffective, if the indiaction for ICD-implantation is clear on a clinical ground.The purpose of this study is to evaluate the strategy of implanting an ICD with or without EPS before during and after ICD-implantation in a randomised controlled trial, using a combined endpoint of major ICD-related adverse events as the primary outcome measure (see details under "Endpoints"). The results will be viewed against the extra costs and patients´ quality of life both study arms.Secondary outcomes are considered as differences in decisions between the groups and difference of events in the two groups.

Inclusion Criteria:

• structural heart disease and survived cardiac arrest or hemodynamically unstable VT (bpm > 200/min)

Exclusion Criteria:

• conditions, which make a secondary cause for cardiac arrest probable or are not compatible with a single chamber ICD; co-morbidity, prior ICD PM, or EPS