Author + information
In previous studies, fragmented QRS (f-QRS) in electrocardiography (ECG) has been shown to be associated with regional myocardial scar. Excluding most risk factors for cardiac diastolic dysfunction, in this study, we sought to evaluate the effect of fragmented QRS on diastolic parameters using the methods of conventional Doppler and tissue Doppler in patients with normal systolic function who have noncritical stenosis demonstrated in the coronary angiography.
This study includes 60 patients with f-QRS in the surface ECG and 40 control patients with similar demographic characteristics without f-QRS in the surface ECG. Demographic characteristics were: prediagnosis of coronary artery disease; several indications, such as ischemic signs in treadmill test / myocardial perfusion scintigraphy with angina symptoms or noncoronary causes (before aortic aneurysm, peripheral arterial disease surgery) for coronary angiography to be performed; normal systolic function; noncritical stenosis, with the ratio of lesion diameter to vessel diameter <50%, and lesion area to vessel area <70%. Diastolic parameters were compared between the two groups using the methods of conventional Doppler and tissue Doppler. Fragmented QRS was defined as the presence of a second R (R’) wave, the notching of R or S wave, or the fragmentation of R wave (more than one R’) in at least two consecutive leads compatible with epicardial coronary arteries. Patients with a history of myocardial infarction, pathological Q waves, typical bundle branch block, incomplete right bundle branch block, or pacemaker rhythm in the ECG were excluded from the study.
Compared with conventional echocardiography, regional tissue Doppler parameters revealed significant differences in patients with f-QRS. Em (tissue Doppler early diastolic velocity) and Em/Am (the ratio of early and late diastolic velocities) from tissue Doppler echocardiography parameters were found to be lower in patients with f-QRS compared with the control group (p<0.05).
According to the results of our study, the presence of f-QRS in the surface ECG is associated with the deterioration of left ventricular diastolic function, both regionally and globally, and this deterioration is more evident at tissue level. In conclusion, fragmented QRS in the surface ECG can be an early predictor of diastolic dysfunction.