Fragmented QRS complex is independently associated with coronary microvascular function in asymptomatic patients with diabetes mellitus

Aim: We aimed to investigate the relation between fragmented QRS (fQRS), coronary flow reserve (CFR), and cardiac dysfunction in asymptomatic patients with type 2 diabetes mellitus (DM). Subjects and Methods: Prospectively, 129 participants with DM (83 males; mean age: 49 ± 12 years). Surface electrocardiograms of all participates were analyzed for the presence of fQRS. Furthermore, individuals were evaluated for CFR, using transthoracic echocardiography with adenosine (0.14 μg/kg). They underwent both conventional and tissue Doppler imaging to evaluate cardiac functions. Lipid profile and fasting blood glucose were obtained. Results: CFR <2.0 was found in 74 (57%), while fQRS was detected in 80 (62%). Individuals with reduced CFR had a higher prevalence of fQRS compared with those with preserve CFR (96% vs. 16%, P < 0.001). Patients with fQRS had a lower CFR compared with those without fQRS (1.6 ± 0.3 vs. 2.7 ± 0.5, P < 0.001). The number of fQRS was inversely correlated with CFR (P < 0.001), S' wave (P < 0.01), and positively correlated with E/e' (P < 0.01), left atrial volume index (P < 0.02), triglycerides/high-density lipoprotein-cholesterol ratio (P < 0.01), and fasting blood sugar (P < 0.05). In addition, reduced CFR was closely correlated with increased E/e' ratio (P < 0.01) and lower S-wave (P < 0.03). On multivariate analysis, fQRS and CFR were independently associated (P < 0.001). ROC revealed that the number of QRS ≥3 was the optimal number (area under the curve = 0.92) to predict microvascular dysfunction. Conclusions: fQRS in asymptomatic patents with DM is associated with subclinical microvascular and left ventricular diastolic dysfunction. These findings revealed that the fQRS in the surface electrocardiography could be considered a simple marker for microvascular dysfunction in patients with DM.