title: The Effect of Glucose Variability on QTc Duration and Dispersion in Patients with Type 2 Diabetes Mellitus.
abstract: OBJECTIVE
  Glycemic variability (GV) is a new term with the episodes of hyper and hypoglycemia in diabetic patients. Both prolonged QT interval and QTd are potential risk factors for malignant ventricular arrhythmias affecting the mortality of different groups of patients including diabetes mellitus. In this study, we aimed to evaluate if the glucose variability increasing the QTc interval and QTc dispersion in type 2 diabetes mellitus.
  
  
  METHODS
  We included 275 consecutive patients with type 2 diabetes. We quantified the GV with standard deviation (SD) and coefficient of variation (CV) from 7 point glucose measures. We investigated the relationship of GV parameters with QT parameters.
  
  
  RESULTS
  The prevalence of prolonged QTc duration was 21%, no patients have prolonged QTc dispersion (> 80 ms). SD of the patients with prolonged QTc duration was significantly higher than the others (45.14 ±24.45 vs. 37.78 ±9.03 p<0.05). There was also a significant relationship between SD and QTc dispersion (r: 0.164; p: 0.007). There were no relationship between the QT parameters and microvascular diabetic complications. SD and HbA1c levels were significantly higher on the patients having peripheral neuropathy (p<0.005).
  
  
  CONCLUSIONS
  The result of this study demonstratess that increased glycemic variability is associated with prolonged QTc duration and QTc dispersion. It is important to focus on targeting optimal glycemic control with GV as an additional goal point along with the traditional following parameters such as fasting-postprandial blood glucose and HbA1c.
authors.affiliation: Yasar Sertbas, MD. Doctor, Department of Internal Medicine, Fatih Sultan Mehmet Education and Research Hospital, Istanbul, Turkey.
authors.forename: Yasar
authors.initials: Y
authors.lastname: Sertbas
authors.affiliation: Ali Ozdemir, MD. Associate Professor, Department of Internal Medicine, Fatih Sultan Mehmet Education and Research Hospital, Istanbul, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Ozdemir
authors.affiliation: Meltem Sertbas, MD. Doctor, Department of Internal Medicine, Fatih Sultan Mehmet Education and Research Hospital, Istanbul, Turkey.
authors.forename: Meltem
authors.initials: M
authors.lastname: Sertbas
authors.affiliation: Akin Dayan, MD, Doctor, Department of Family Medicine, Haydarpasa Numune Education and Research Hospital, Istanbul, Turkey.
authors.forename: Akin
authors.initials: A
authors.lastname: Dayan
authors.affiliation: Seda Sancak, MD. Associate Professor, Department of Endocrinology, Fatih Sultan Mehmet Education and Research Hospital, Istanbul, Turkey.
authors.forename: Seda
authors.initials: S
authors.lastname: Sancak
authors.affiliation: Cihangir Uyan, MD. Professor, Department of Cardiology, Fatih Sultan Mehmet Education and Research Hospital, Istanbul, Turkey.
authors.forename: Cihangir
authors.initials: C
authors.lastname: Uyan
keywords: Glucose variability; QT duration; QTc dispersion