Despite the implementation of modern therapy for acute myocardial infarction (AMI), the substrate for fatal ventricular tachycardia/fibrillation develops frequently. Primary prevention therapy by implantable cardioverter–defibrillator (ICD) to reduce the risk of sudden cardiac death is recommended in post-MI patients with significant left ventricular (LV) dysfunction. While the benefit of ICD therapy in chronic post-MI patients has been firmly established, the implantation of ICDs in the early post-MI period is not warranted. LV dysfunction has been a major determinant for entry into the primary preventative ICD trials. Currently, numerous risk stratifiers are under investigation in order to improve the efficacy of ICD therapy. More specific selection of patients at risk of preventable cardiac death, based on more than simply ejection fraction, is crucial for the future development of cost-effective prophylactic treatments aimed at closing the gap between scientific evidence and the limited resources of healthcare systems.