Abstract :Fragmented QRS complexes (fQRS) on a 12-lead ECG are a marker of depolarization abnormality. FQRS represents conduction delay from inhomogeneous activation of the ventricles due to myocardial scar. It has a high predictive value for myocardial scar and mortality in Coronary Arterial Disease. However, fQRS is a nonspecific finding and its diagnostic prognostic should only be interpreted in the presence of pertinent clinical evidence and type of myocardial involvement (structural vs. structurally normal heart).The purpose of this review is to discuss the potential utility of tests to detect depolarization abnormalities of the heart for the risk stratification of mortality and sudden cardiac death with main emphasis on fQRS.