Fragmented QRS on surface electrocardiogram is not a reliable predictor of myocardial scar, angiographic coronary disease or long term adverse outcomes

Up to a quarter of all myocardial infarctions go unrecognized (1,2). Currently, the identification of Q waves on more than two contiguous leads seems to be the best tool we have on electrocardiography to detect prior myocardial infarctions (3). However, Q waves can disappear over time in 25-60% of patients and autopsy studies have failed to show consistent correlation between transmurality of infarct and Q waves (4,5). Additionally, magnetic resonance imaging (MRI) studies have shown that Q waves have low sensitivity for prediction of overall location of scars (6). Thus, there is an unmet need for better and readily available tools to detect prior myocardial injury in daily practice. Alterations in QRS morphology, rsR and its variants called fragmented QRS (fQRS) have been shown to occur on surface electrocardiogram (EKG) by studies many years ago (7,8). More recently, fQRS was demonstrated to have high sensitivity and specificity to detect myocardial scar on single-photon emission computed tomography (SPECT) perfusion imaging (4). However, despite recent retrospective studies demonstrating that the presence of fQRS in patients with ischemic cardiomyopathy is a reliable marker of infarct size, the evidence is conflicting regarding the utility of fQRS as one group in a more recent study has refuted an association of fQRS with SPECT scar (2,9). Given this conflicting evidence on fQRS and lack of angiographic correlation to SPECT in prior studies, we aimed to study our patient population undergoing SPECT and coronary angiography (CA) for further defining if fQRS has the capability of predicting SPECT scar and correlate it to CA (10). We further also aimed to study the impact of fQRS on outcomes in these patients over a long term follow-up period of 5 years