Incidence of QTc Prolongation in Type 2 Diabetes Mellitus and it´s Relation to Cardiac Autonomic Neuropathy

Taha O. Mahwi, Rasool M. Hasan, Hero I. Faraj


Recently there has been growing interest in the relationship between diabetes and QTc. Prevalence of prolonged QTc interval is higher in people with type 2 diabetes as compared to non-diabetic subjects, especially in the presence of autonomic neuropathy. QTc prolongation in diabetic autonomic impairment has been reported by numerous authors and also has been reported to lead to sudden death.
Objective: The main aim of this study is to estimate the incidence of QTc prolongation in type 2 diabetes mellitus and its relationship to cardiac autonomic neuropathy.
Methods: From January 2009 to September 2009, we enrolled 150 type 2 diabetic patients attending the Sulaimani diabetic centre. We also enrolled 100 non diabetic control groups.
Both group underwent measurement of QT interval, subsequently QTc estimated according to Bazett equation. We also performed 5 cardiovascular autonomic tests including resting heart rate measurement, heart rate variation with inspiration and expiration, valsalva maneuver, blood pressure response to handgrip and standing.
Results: Among the 150 cases 13 were found to have prolonged QTc (8.7%), 11 were females 2 were males (p value 0.041). No one in the control group showed prolonged QTc. Regarding cardiac autonomic neuropathy (CAN), 106 cases had CAN 35, 40 and 31 for early, definite and severe cases, respectively. There was significant correlation between QTc & CAN (p value 0.000) QTc prolongation was significantly related with increasing age (p value 0.010) and female gender (p value 0.041) but no relationship was found with duration of DM (p value 0.520).
Sensitivity of prolonged QTc for detection of CAN was 20%, with specificity and positive predictive value of 98.7% and 92.3%, respectively.
Conclusions: We realized that QTc prolongation occur in cardiac autonomic neuropathy due to DM and it´s highly specific for CAN but insensitive. It is significantly correlated with age & gender but no relation found with duration of DM.


QTc Prolongation, Cardiac Autonomic Neuropathy, Diabetes Mellitus.

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