(Hellenic Journal of Cardiology) HJC • 301 Hellenic J Cardiol 2013; 54: 301-315 Review Article Review Article Manuscript received: July 26, 2012; Accepted: April 29, 2013. Address: Petros Arsenos 12 Chalkidos-Athinon St. 190 11 Avlonas Attikis, Greece e-mail: arspetr@otenet.gr Key words: Sudden cardiac death, risk stratification strategies, post- myocardial infarction patient, non-invasive screening, electrophysiological testing, heart rate dynamics. Arrhythmic Sudden Cardiac Death: Substrate, Mechanisms and Current Risk Stratification Strategies for the Post-Myocardial Infarction Patient Petros Arsenos 1 , KonstAntinos GAtzoulis 1 , Polychronis DilAveris 1 , GeorGe MAnis 2 , DiMitrios tsiAchris 1 , stefAnos ArchontAKis 1 , APostolis h. vouliotis 1 , sKevos siDeris 1 , christoDoulos stefAnADis 1 1 Electrophysiology Laboratory & First Department of Cardiology, Medical School, National and Kapodistrian University of Athens, Athens, 2 Department of Computer Science, University of Ioannina, Ioannina, Greece F or practical reasons, and to over- come potential ambiguities in the existing previous definitions, it was proposed that the term “sudden car- diac death” (SCD) should signify a natu- ral death from cardiac causes, heralded by an abrupt loss of consciousness within one hour of the onset of acute symptoms. 1 Be- cause fatal ventricular tachycardia and fi- brillation (VT/VF) do cause SCD, this en- tity has emerged as a tachyarrhythmia sur- rogate and is used as a classification end- point in relevant clinical studies. 2 How- ever, many other pathophysiological con- ditions that evolve rapidly can also lead to unexpected death, and in fact the clini- cal diagnosis of SCD is not synonymous with VT/VF in every case. 3 Additionally, recent studies of patients with implant- ed cardiac defibrillators (ICDs) indicate that many of the deaths defined as sudden were not due to tachyarrhythmia. 4 There- fore, the following limitation should be taken into consideration: although SCD usually comes as a consequence of malig- nant tachyarrhythmia, this is not always the rule. This article presents, in a com- prehensive way, the issue of SCD of ar- rhythmic aetiology in patients suffering from coronary artery disease (CAD). The potential arrhythmogenic substrate, the mechanisms for arrhythmia initiation and current strategies for SCD risk stratifica- tion are described, with emphasis on their clinical applicability. Epidemiology of coronary artery disease and SCD The annual incidence of SCD in Europe and North America is estimated to be ap- proximately 1 episode per 1000 persons. 5 SCD is significantly associated with CAD and almost 50% of deaths occurring in myocardial infarction (MI) survivors are of sudden origin. 5,6 The risk of arrhythmic death in post-MI survivors has a tempo- ral trend, with the highest death rate ob- served in the first 6 months after MI and remaining high for the next 2 years. 7 Prevention of SCD Previous studies established the role of the ICD for protection against ventricu- lar tachyarrhythmias, 8-10 and the current guidelines recommend the ICD for the primary prevention of SCD in post-MI pa-