Fragmented QRS: a predictor of mortality and sudden cardiac death

Several invasive and noninvasive tests for risk stratification of sudden cardiac death have been studied, mostly in the context of structural heart disease such as coronary artery disease (CAD), cardiomyopathy, and heart failure. Tests such as MTWA (repolarization abnormality) and SAECG (depolarization abnormality) have high negative predictive values but a low positive predictive value in patients with myocardial infarction or cardiomyopathy. Recently, we described the presence of a fragmented QRS complexes (fQRS) on a routine 12-lead electrocardiogram as another marker of depolarization abnormality. fQRS represents conduction delay caused by myocardial scar in patients with CAD. However, fQRS is not specific for CAD and is also encountered in other myocardial diseases such as cardiomyopathy and congenital heart disease. fQRS is associated with increased mortality and arrhythmic events in patients with CAD. fQRS has also been defined as a marker of arrhythmogenic right ventricular dysplasia/cardiomyopathy and Brugada syndrome. In Brugada syndrome, the presence of fQRS predicts episodes of ventricular fibrillation during follow-up. Therefore, the utility of fQRS in risk stratification of sudden cardiac death needs to be explored further, especially in nonischemic cardiomyopathy and heart failure.