Serum glucose and insulin are associated with QTc and RR intervals in nondiabetic elderly

Abstract

Aims: To study whether nondiabetic persons with impaired fasting serum glucose and hyperinsulinemia have QTc/QT interval prolongation and RR interval shortening in the electrocardiogram (ECG), and whether these were associated with an increased risk of sudden cardiac death. Methods: This study consisted of two analyses. First, a cross-sectional analysis was used as part of the population-based Rotterdam Study including 1050 men and 1520 women (R55 years) without diabetes mellitus. Participants in round 3 of the Rotterdam Study for whom an ECG and fasting serum glucose and fasting insulin measurements were available were eligible for the study. Participants using digoxin or QTc-prolonging drugs and participants with left ventricular hypertrophy and left and right bundle branch block were excluded. The endpoints of the study were the lengths of the QTc, QT, and RR intervals. The associations were examined by means of linear regression analysis. Secondly, in all 6020 participants of the Rotterdam Study with an ECG, the associations between the QTc, QT, and RR intervals and sudden cardiac death were examined by means of Cox regression analysis. Results: Overall, there was a significant association between impaired fasting serum glucose and the QTc interval with an increase of 2.6 ms (95% confidence interval (CI): 0.3; 5.0) in those with fasting glucose O6 mmol/l. Hyperinsulinemia was also associated with QTc prolongation (3.0 ms (0.8; 5.3)) in those with fasting insulin R100 pmol/l. Impaired fasting glucose (IFG) and hyperinsulinemia were significantly associated with a decrease of the RR interval (K33.7 ms (K48.8; K18.6) and K44.4 ms (K58.7; K30.0) respectively). Participants in the fourth quartile of the QTc and QT intervals had a significantly increased risk of sudden cardiac death compared to participants in the first quartile (hazard ratio (HR) 2.87 (95% CI: 2.02-4.06); HR 3.05 (1.99-4.67) respectively). Furthermore, there was a significant inverse association between the fourth quartile of the RR interval compared to the first quartile and the risk of sudden cardiac death )).Conclusion: In this population-based study, we demonstrated that IFG and hyperinsulinemia are associated with a significantly increased QTc interval and with significant shortening of the RR interval, the latter probably due to an increased sympathetic activity. In addition, we demonstrated that both a prolonged QTc interval and a shortened RR interval are associated with an increased risk of sudden cardiac death.

KCNQ1 Long QT Syndrome Patients Have Hyperinsulinemia and Symptomatic Hypoglycemia

“…The insulin-induced hypokalemia will also decrease the repolarization reserve by a reduction of the rapid delayed rectifier current I Kr (36), thus further increasing the risk of cardiac arrhythmia and cardiac arrest (34). Furthermore, in a population-based study of 2,570 elderly people without diabetes it was demonstrated that hyperinsulinemia was associated with significantly increased QT interval and increased risk of sudden death (37). In addition, a recent study revealed that QT prolongation and hypokalemia were common in diabetic patients with severe hypoglycemia, which increased their risk of fatal arrhythmia and death (38).…”

Hyperglycemia Is Associated With Corrected QT Prolongation and Mortality in Acutely Ill Patients

“…26 Importantly, it has also been shown that a prolonged QTc interval is associated with increased risk for sudden cardiac death in these ambulatory populations. 27 A postulated mechanism underlying the glucose-QTc interval relationship is parasympathetic tone, namely heart rate variability. 26 …”

QT Interval Shortening After Bariatric Surgery Depends on the Applied Heart Rate Correction Equation

“…Insulin may play a particular role in this context, since bariatric surgery has been shown to rapidly reduce circulating insulin levels [24]. Moreover, several previous cross-sectional studies have revealed an independent association between circulating insulin levels and QTc interval length [25,26]. Interventional studies, however, have revealed a less consistent picture where intravenous insulin infusion acutely increased QTc interval length in normal weight [27] but not in obese subjects [28] under euglycemic conditions.…”