The fragmented QRS: does it really indicate a ventricular abnormality?

Notching of R and S waves in the QRS complex can result from myocardial infarction. As defined in recent studies, the 'fragmented QRS' (fQRS) showed high sensitivity and specificity for the presence of myocardial scar as imaged by myocardial perfusion scanning in participants studied for ischemic heart disease. The present study attempted to determine the significance of the fQRS in electrocardiograms of patients who had myocardial imaging for a variety of reasons by a variety of methods.

From a series of electrocardiograms, 218 patients were found with fQRS without abnormal Q waves, but with myocardial imaging by myocardial perfusion scanning or echocardiography. Another 214 patients without fQRS but having had one of these imaging methods were also studied. An additional 106 patients with or without fQRS were selected for having undergone cardiac magnetic resonance imaging with studies for late gadolinium enhancement.

Myocardial perfusion scanning, echocardiography, or magnetic resonance imaging revealed a ventricular myocardial abnormality in 52.6% of patients with fQRS and in 29.7% without fQRS (P < 0.0001). Ischemic heart disease was present in only 27% of patients showing fQRS. An electrocardiographic point score system was devised that helped to differentiate tracings having an fQRS with a ventricular abnormality from those without the latter.

The utility of fQRS varies with the incidence of ventricular disease in the population studied. This electrocardiographic sign is commonly associated with ventricular abnormalities with and without demonstrable myocardial scar, but also occurs in the absence of clinical heart disease.