Early period after myocardial infarction (MI) in patients with an impaired left ventricular function is associated with the highest risk of sudden cardiac death (SCD).Implantable cardioverter-defibrillator (ICD) is a therapeutic option which may save these patients from sudden death due to lethal ventricular arrhythmias.However in DINAMIT and IRIS studies, both incorporating patients with recent MI and reduced left ventricular ejection fraction (LVEF), there was no effect of ICD on all-cause mortality-in fact the benefit from ICD therapy was completely offset by the increased mortality from non-arrhythmic causes.One of the reasons of this problem may be the fact, that almost all important clinical risk factors of SCD, including low LVEF, are associated with the increased risk of death from any causes.As a consequence, patients stratified with these risk factors are under the threat of all-cause but not specifically cardiac or sudden cardiac death.If we are to use ICD in a cost-effective way, we need risk-stratification tests which identify patients whose risk of arrhythmic death considerably exceeds their risk of other modes of death such a group would fully benefit from ICD therapy.Alternatively, tests identifying patients at high risk of non-cardiac death might select those who would not benefit from ICD therapy due to their severe non-cardiac burden.