The effect of insulin resistance on ventricular repolarization values in obese children and adolescents

The Aim: Obesity with increasing frequency is an important health problem, because of its increasing effect on the morbidity and mortality. Coronary hearth disease is World's leading cause of death and obesity is one of tehe causes of coranary heart diseases. Obesity can increase the risk of arrhythmia by predisposing to cardiovascular diseases, abnormalities of ventricular repolarization may increase the sensitivity of the heart to ventricular arrhythmias, leading to sudden cardiac death. It is not known whether insulin resistance contributes to these abnormalities. Our study aims to investigate whether insulin resistance has an effect on cardiac conduction system in obese patients. Materials and Methods: 50 obese and 47 healthy children and adolescents between the ages of 6 and 18 and whose BMI was above the 95th percentile were included in the study. After physical examination and anthropometric measurements of all cases, biochemical tests were performed, ECG was performed, ECG waves and intervals were measured manually by magnifying with TorQ 150 mm Digital Caliper LCD device. Results: Of the obese group, 19 were male (38%), 31 were female (62%) and 27 were child (54%), 23 were adolescent (46%) and their ages were 11.3 ± 3.5 years. these characteristics were similar when compared, but the FBS (p = 0.05), insulin (p = 0.001), HOMA-IR (p = 0.005), HbA1c (p <0.001), triglyceride (p <0.001) and ECG parameters; QTc (p = 0.001) ), QTd (p <0.001), QTdc (p <0.001), JTc (p <0.001), Tpe (p <0.001), Tpe / QTort (p <0.001), Tpe / QTc (p <0.001), Tpe / JT (p <0.001) and Tpe / JTc (p <0.001) were significantly different. Twenty-five (50%) of the obese patients had insulin resistance, compared to those without insulin resistance FBG (p = 0.016), insulin (p = 0.005), HOMA-IR (p = 0.013), triglyceride (p <0.001) and only JTc was statistically different in the ECG (321.7 ± 17.7 vs. 332.3 ± 16.5 ms, p = 0.033). In patients with Insulin resistance, JTc correlated with cholesterol (p = 0.008), QTc (p <0.001), JT (p = 0.015), cholesterol / HDL (p = 0.048), QRS duration (p = 0.016), Tpe (p = 0.006), Tpe / QT average ( p = 0.003), Tpe / QTc (p <0.001), Tpe / JT (p <0.001) and Tpe / JTc (p <0.001). JT (p <0.001) and QTc (p <0.001) had the greatest effect on JTc duration. The 327 ms cut-off value of JTc indicates insulin resistance in obese subjects (AUC: 0.66, 95% CI (0.51-0.81), p = 0.044) (sensitivity 60%, specificity 60%) Conclusion: Obesity causes ventricular repolarization abnormalities. Insulin resistance associated with obesity increases this risk even further. JTc, an ECG parameter, may be helpful in assessing ventricular repolarization abnormalities and arrhythmia risk in such patients.