Relationship between QRS characteristics and delayed-enhancement cardiac magnetic resonance in patients with ischemic cardiomyopathy

•QRS fragmentation was related to left ventricular size, systolic function, and fibrosis.•Q waves were related to fibrosis and left ventricular function.•QRS duration was related to left ventricular size and systolic function.•Forty percent of patients with normal QRS had evidence of fibrosis.

BackgroundWe explored the relationship between QRS characteristics and myocardial phenotype by delayed-enhancement cardiac magnetic resonance (DE-CMR) in patients with coronary heart disease (CHD).Methods and resultsEighty five consecutive patients with CHD that were referred for DE-CMR evaluation constituted the study population. Of a total of 1445 left ventricular (LV) segments evaluated, 346 (23.9%) segments had fibrosis.Compared to patients without pathological Q waves, patients with pathological Q waves showed a higher number of segments with fibrosis (5.9 ± 3.1 vs. 2.7 ± 2.8, p < 0.001), and lower left ventricular ejection fraction (LVEF) (42.9 ± 13.6% vs. 51.8 ± 18.3, p = 0.01); whereas no significant differences were observed regarding LV size.When discriminated in according to the QRS duration tertiles, no significant differences were observed regarding the number of segments with fibrosis (p = 0.34), whereas the highest QRS tertile was related to the presence of a low LVEF (p = 0.005) and larger LV size (p = 0.01). QRS fragmentation (fQRS), defined as the presence of an R′ or notching in the nadir of the R wave or the S wave, or the presence of >1 R′ in 2 contiguous leads, was significantly related to LV size (LV end diastolic volume 153.6 ± 81.6 ml, vs. 111.5 ± 41.4 ml, p = 0.003), function (LVEF 43.2 ± 15.9% vs. 53.6 ± 16.3%, p = 0.005), and extent of fibrosis (5.1 ± 3.4 segments vs. 3.2 ± 3.1 segments, p = 0.01).ConclusionsIn the present study, fQRS was the only QRS-derived variable systematically and more closely related to LV size, LV systolic function, and to the presence and extent of fibrosis.