The clinical utility of QT interval assessment in diabetes

A prolonged (QT) interval is considered an indicator of an increased risk o f malignant ventricular arrhythmias and/or sudden death. It has been propos ed that autonomic neuropathy in diabetes is related to QT interval prolonga tion and higher mortality rates. More recently, the inter-lead difference i n QT interval duration has been referred to as QT interval dispersion, whic h has proven to be predictive of ventricular arrhythmias and mortality in d ifferent groups of patients. QT interval duration and dispersion are signif icantly related, but are not concordant in a substantial number of cases in identifying patients at risk, The prevalence of QT prolongation in Type 1 and Type 2 diabetic (T1 and T2DM) patients is higher than 20%, Several stud ies in T1 and T2DM patients have confirmed the independent relation between prolonged QT interval duration and increased QT interval dispersion and ch ronic ischemic heart disease. It has been consistently shown that autonomic neuropathy is related to QT interval duration, while more controversies ex ist on the association with QT interval dispersion. In recent years 5 studi es have been published which confirm the value of QT interval as a predicto r of total mortality in diabetic as well as in non-diabetic subjects. Surpr isingly, no data exist on the relation between the risk of sudden death and QT interval prolongation in diabetic patients. As corrected QT interval is significantly related to mortality, it could be used to stratify the death risk in diabetic patients, particularly those who are candidates for surge ry or kidney and/or pancreas transplantation. We still do not know why QT i nterval is prolonged and how this abnormality leads to death: however, a si mple, low-cost measurement, which is easily obtainable without the need of the patient's compliance, could help select patients who need second level diagnostic procedures and strict observation. (C) 2000, Editrice Kurtis.