Fragmented QRS frequency in patients with cardiac syndrome X

Cardiac syndrome X (CSX) is characterised by typical exertional chest pain, a positive response to exercise testing, and a normal coronary angiography. The relationship of CSX with myocardial fibrosis and ischemia has been clearly demonstrated in previous studies. In addition, fragmented QRS (fQRS) has been reported in the literature as an indicator of myocardial fibrosis. The aim of this study was to investigate the frequency of fQRS in patients with CSX.

This prospective case-control study included 37 patients (CSX group) with typical complaints of angina, ischemia on an exercise test, and normal coronary arteries as detected by angiography and 47 patients (control group) with normal coronary arteries. Echocardiographic examinations were performed according to the recommendations of the American Society of Echocardiography. Continuous variables were expressed as mean±standard deviation (SD), and the qualitative variables were expressed as a percentage or ratio. Data were compared statistically with Shapiro-Wilk test, Student's t-test, Mann-Whitney U, chi-square and Fisher exact test.

There was no significant difference between the CRX and control groups with respect to basic characteristics such as age and sex. fQRS and the frequency of its presentation with stable angina pectoris at the clinic were significantly higher in the CSX group than in the control group (p values: 0.001 and <0.001, respectively).

A close follow-up would be useful in CSX patients in whom fQRS is detected in an electrocardiogram (ECG) because of the association between fQRS and poor prognosis with respect to the prevention of late complications. We believe that the presence of fQRS in the ECG aids in the diagnosis of CSX in clinical practice and in the recognition of this group of patients.