QTc Prolongation in Pediatric Patients with Diabetic Ketoacidosis

The role of mitochondrial dysfunction in the association between trace metals and QTc prolongation in the aged population

This study delves into the relationship between environmental metal exposure and QT interval corrected for heart rate (QTc) prolongation, a critical marker for cardiovascular risk in the elderly. Although the interplay between metal exposure and QTc prolongation is important for predicting sudden cardiac death, it remains underexplored. Our analysis of 6478 participants from the Shenzhen aging-related disorder cohort involved measuring urinary concentrations of 22 trace metals and using mitochondrial DNA copy number (mtDNA-CN) as an indicator of mitochondrial dysfunction. Utilizing Bayesian kernel machine regression, and structural equation modeling, we assessed the effects of mixed trace metals on QTc prolongation. Our findings indicated a direct association between certain metals (Sb, Cu, Zn) and a 7 % increase in QTc prolongation risk, while Li, V, and Rb were associated with a 5 % reduction in risk. Elevated levels of V, Ti, and Cr corresponded to higher mtDNA-CN. Notably, restricted cubic splines revealed a U-shaped, nonlinear relationship between mtDNA-CN and QTc prolongation. After adjusting for metal exposure, an inverse correlation was observed between mtDNA-CN and QTc prolongation, suggesting mitochondrial dysfunction as a partial mediator.

Cardiometabolic risk factors and electrocardiogram results in type 2 diabetes patients with or without non-infected foot ulcers: A comparative study

BACKGROUND: Numerous investigations have demonstrated that type-2 diabetes (T2D) causes electrocardiographic alterations, whether or not there are microvascular or macrovascular problems.

AIM: With respect to glycemic control and the accompanying cardio-metabolic risk factors, the goal of this study was to demonstrate the variations in electrocardiogram records between T2D patients with non-infected diabetic foot ulcers (DFUs) and those without ulcers.

METHODS: This study was performed in the Shar Teaching Hospital in the Sulaimani Governorate-Iraq from July 2018 to June 2019. 167 participants were grouped into Group I (T2D, n=72); Group II (T2D with non-infected diabetic foot ulcers, n=65) and Group III (healthy subjects, n= 30). Blood pressure, electrocardiography, and anthropometric measurements were taken. Fasting serum glucose and lipid profiles were assessed as part of laboratory tests.

RESULTS: Group II patients significantly differed from Group I by having lower diastolic blood pressure, a higher pulse pressure index, and a higher fasting serum glucose. The Group I patients had a significantly higher heart rate, a shortening of TQ-interval and widening of QRS dispersion. Group II patients had a significantly shorter TQ-interval compared with the corresponding value of Group I patients (523.6±136.4ms versus 579.2±110.0ms, respectively). These changes in the electrocardiograms are not related to the cardiometabolic risk factors.

CONCLUSION: In the non-infected diabetic foot, the TQ-interval, a measure of ventricular repolarization impairment, is much shorter and is linked to a broad pulse pressure. According to this finding, the electrocardiographic abnormalities are a result of cardiovascular autonomic dysfunction.

Heart rate-corrected QT interval: A novel diagnostic biomarker for diabetic peripheral neuropathy

AIMS/INTRODUCTION

To explore the relationship between heart rate-corrected QT (QTc) interval and diabetic peripheral neuropathy (DPN), and whether QTc interval has diagnostic utility for DPN beyond nerve conduction velocity.

MATERIALS AND METHODS

A total of 965 patients with diabetes, including 473 patients with DPN and 492 patients without DPN, underwent standard 12-lead electrocardiography and detailed assessments of peripheral neuropathy.

RESULTS

Patients with DPN had longer QTc intervals than those without. Among participants, from the first to fourth quartile of QTc interval, the proportion of patients with DPN appreciably increased and the nerve conduction velocity obviously decreased (P for trend <0.001). The univariate and multivariate analyses showed that prolonged QTc interval was closely associated with increased risk of DPN (univariable odds ratio 1.112, 95% confidence interval 1.097-1.127, P < 0.001; multivariable odds ratio 1.118, 95% confidence interval 1.099-1.137, P < 0.001). Receiver operating characteristic analysis for the diagnosis of DPN showed a greater area under the curve for QTc interval of 0.894 than the median nerve motor conduction velocity of 0.691, median nerve sensory conduction velocity of 0.664 and peroneal nerve motor conduction velocity of 0.692. The optimal cut-off point of QTc interval for DPN was 428.5 ms with sensitivity of 0.715 and specificity of 0.920 (P < 0.001). The combination of QTc interval and nerve conduction testing increased the area under the curve for the diagnosis of DPN (from 0.736 to 0.916; P < 0.001).

CONCLUSIONS

QTc interval with 428.5 ms has more reliable diagnostic utility for DPN than nerve conduction velocity, and prolonged QTc interval is closely associated with an increased risk of DPN.

Autonomic cardiac regulation during spontaneous nocturnal hypoglycemia in children with type 1 diabetes

BACKGROUND

Hypoglycemia is the most common complication in insulin treated diabetes. Though mostly mild, it can be fatal in rare cases: It is hypothesized that hypoglycemia related QTc prolongation contributes to cardiac arrhythmia.

OBJECTIVE

To evaluate influence of nocturnal hypoglycemia on QTc and heart rate variability (HRV) in children with T1D.

METHODS

Children and adolescents with T1D for at least 6 months participated in an observational study using continuous glucose monitoring (CGM) and Holter electrocardiogram for five consecutive nights. Mean QTc was calculated for episodes of nocturnal hypoglycemia (<3.7 mmol/L) and compared to periods of the same duration preceding hypoglycemia. HRV (RMSSD, low and high frequency power LF and HF) was analyzed for different 15 min intervals: before hypoglycemia, onset of hypoglycemia, before/after nadir, end of hypoglycemia and after hypoglycemia.

RESULTS

Mean QTc during hypoglycemia was significantly longer compared to euglycemia (412 ± 15 vs. 405 ± 18 ms, p = 0.005). HRV changed significantly: RMSSD (from 88 ± 57 to 73 ± 43 ms) and HF (from 54 ± 17 to 47 ± 17nu) decreased from before hypoglycemia to after nadir, while heart rate (from 69 ± 9 to 72 ± 12 bpm) and LF (from 44 ± 17 to 52 ± 21 nu) increased (p = 0.04).

CONCLUSION

A QTc lengthening effect of nocturnal hypoglycemia in children with T1D was documented. HRV changes occurred even before detection of nocturnal hypoglycemia by CGM, which may be useful for hypoglycemia prediction.

Ventricular tachycardia in an adolescent with severe diabetic ketoacidosis

Diabetic ketoacidosis (DKA) occurs frequently among children and adolescents with type 1 diabetes. Although a number of complications may occur during episodes of DKA, significant cardiac arrhythmias are uncommon. We present the case of an adolescent who presented with severe DKA and wide complex tachycardia that was unresponsive to multiple doses of adenosine and ultimately required synchronized cardioversion. This case reminds the clinician of the importance of cardiac monitoring in children with DKA, particularly in the setting of hyperkalemia.