QT and QTc dispersion are accurate predictors of cardiac death in newly diagnosed non-insulin dependent diabetes: cohort study

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

“…In addition to findings of previous reports, we also observed a relation between elevated rHR and both cardiac mortality and mortality due to ischaemic heart disease. On the other hand, the present analysis did not confirm an association between QT c and any of the endpoints in type 2 diabetes as has been reported previously [6,7,9,10,35]. Given previous hypotheses that prolongation of QT c as a marker of cardiac autonomic neuropathy could be of greater importance in type 1 than in type 2 diabetes [5], our findings on this count are intriguing, and it can only be speculated on the underlying mechanisms.…”

“…Compared with previous publications reporting an association of QT c with mortality in type 2 diabetes [9,10,35], subjects with type 2 diabetes were substantially younger in the present study. It should also be noted that some earlier reports revealing an association between QT c and mortality were cross-sectional [35] or based on a case-control design [9] and in the case of prospective trials [6,7,10] had a considerably shorter follow-up. 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. Although the models used in this analysis were adjusted for the preexistence of coronary heart disease, we could not fully rule out a potential interference due to silent heart disease in subjects with diabetes, since invasive cardiac procedures were not performed.…”

“…However, the association between QT c and cardiovascular mortality in type 2 diabetes is controversial. Some reports suggest that QT c correlates with an increase in cardiovascular mortality [6][7][8][9]. Others have indicated that QT dispersion might more accurately predict cardiovascular mortality in this patient group [10][11][12].…”

Exercise blood pressure correlates with the maximum heart rate corrected QT interval in hypertension

“…6 The maximum QT c interval (QT c max), like QT dispersion is also a potent predictor of (sudden) cardiac death. [7][8][9][10] A large population study 8 involving nearly 3500 subjects aged 30-60 years followed up over a period of 11 years suggested that subjects with a QT c max у 430 ms (vs Ͻ 360 ms) had three times the risk of suffering cardiac death.…”