The relation between QTc interval prolongation and diabetic complications. The EURODIAB IDDM Complication Study Group

Abstract

The QT interval reflects the total duration of ventricular myocardial depolarization and repolarization: a prolonged QT interval is associated with sudden death and poor survival in apparently healthy subjects [1]. The relation of QT interval prolongation with diabetes complications, poor survival prognosis and sudden death has recently received considerable interest. It has been postulated that QT prolongation accounts for higher mortality in people with diabetes and its complications as the prevalence of QT interval prolongation is higher among patients with Type I (insulin-dependent) diabetes mellitus [2], ischaemic heart disease (IHD) [3±7], end stage renal disease [8] and autonomic neuropathy [2, 9±12].Data on QT interval in diabetic patients are, however, mainly derived from small, selected samples [9±15]. In particular, the prevalence of QT interval prolongation and its relation with cardiac autonomic neuropathy has been evaluated in only one cross-sec- Diabetologia (1999) Summary The prevalence of QT interval prolongation is higher in people with diabetes and its complications. Sudden death has been reported as a common cause of death in insulin-dependent diabetic patients affected by autonomic neuropathy. It has been postulated that QT prolongation predisposes to cardiac arrhythmias and sudden death. In this analysis the prevalence of QT interval prolongation and its relation with diabetic complications were evaluated in the EURODIAB IDDM Complications Study (3250 insulin-dependent diabetic patients attending 31 centres in 16 European countries). Five consecutive RR and QT intervals were measured with a ruler on the V5 lead of the resting ECG tracing and the QT interval corrected for the previous cardiac cycle length was calculated according to the Bazett's formula. The prevalence of an abnormally prolonged corrected QT was 16 % in the whole population, 11 % in males and 21 % in females (p < 0.001). The mean corrected QT was 0.412 s in males and 0.422 s in females (p < 0.001). Corrected QT duration was independently associated with age, HbA 1 c and blood pressure. Corrected QT was also correlated with ischaemic heart disease and nephropathy but this relation appeared to be stronger in males than in females. Male patients with neuropathy or impaired heart rate variability or both showed a higher mean adjusted corrected QT compared with male patients without this complication. The relation between corrected QT prolongation and autonomic neuropathy was not observed among females. In conclusion we have shown that corrected QT in insulin-dependent diabetic female patients is longer than in male patients, even in the absence of diabetic complications known to increase the risk of corrected QT prolongation. [Diabetologia (1999) 42: 68±75]

QTc interval and resting heart rate as long-term predictors of mortality in type 1 and type 2 diabetes mellitus: a 23-year follow-up

“…To our knowledge, this is the first study to prospectively assess the role of QT c and rHR in both types of diabetes within the same study framework. Its findings confirm the prognostic value of QT c as an independent risk factor for all-cause mortality in type 1 diabetes [5,[28][29][30]. In addition to the results of Rossing et al [5], the present…”

“…The HR for overall mortality found in the present analysis was comparable to that in Rossing's report [5], but tended to be lower than the risk ratio found in subjects with overt nephropathy [28] (1.10 and 1.47 per 10 ms, respectively). Earlier reports have suggested that the association between QT c and cardiovascular disease was stronger in male than in female subjects with type 1 diabetes [30]. The present study had slightly more female subjects in the group with type 1 diabetes, thereby potentially underestimating the prognostic value of QT c for this patient group.…”

“…In subjects with type 1 diabetes an increased prevalence of prolonged QT c has been reported before [30,36], in particular in subjects with autonomic neuropathy [36][37][38]. This may indicate that increased QT c relates to diabetic autonomic neuropathy [39].…”

“…In type 2 diabetes hyperglycaemia is often associated with a pro-inflammatory state including obesity, dyslipidaemia and hypertension, thereby promoting the development of atherosclerosis [41]. Interestingly, impaired myocardial oxygen supply has also been shown to influence QT interval [28,30]. As has been pointed out before [6,10], QT c is possibly a composite marker, reflecting abnormal ventricular repolarisation due to ischaemia, fibrosis, left ventricular hypertrophy and dilatation, autonomic neuropathy, and vascular damage, conditions frequently present in diabetic myocardium.…”

Multivariate associates of QT interval parameters in diabetic patients with arterial hypertension: importance of left ventricular mass and geometric patterns

“…13 In patients with arterial hypertension, QT interval parameters have mainly been associated with left ventricular mass (LVM), [14][15][16][17][18] although a recent report suggested that they are no better than simple electrocardiographic voltage criteria for detection of left ventricular hypertrophy (LVH). 19 In diabetic patients, QT parameters have been correlated not only with the presence of cardiac dysautonomia, 20 coronary artery disease, 21 diabetic degenerative complications 22 and microalbuminuria, 23 but also with the presence of arterial hypertension and LVH. 24 In view of these reports, we investigated in a cross-sectional design study the relationships between five QT interval parameters (maximal QT and QT c duration, and QT, QT c and number of leads-adjusted QT interval dispersion) and several clinical, electrocardiographic and 2D echocardiographic variables, with particular attention to their associations with LVM and geometric patterns, since they constitute important prognostic factors in patients with arterial hypertension.…”