Electrocardiographic changes in children with diabetic ketoacidosis and ketosis

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.

Effect of the ketogenic diet in excitable tissues

In the past decade, ketogenic diet (KD) has gained some popularity as a potential treatment for a wide range of diseases, including neurological and metabolic disorders, thanks to a beneficial role mainly related to its anti-inflammatory properties. The high-fat and carbohydrate-restricted regimen causes changes in the metabolism, leading, through the β-oxidation of fatty acids, to the hepatic production of ketone bodies (KBs), which are used by many extrahepatic tissues as energy fuels. Once synthetized, KBs are delivered through the systemic circulation to all the tissues of the organism, where they play pleiotropic roles acting directly and indirectly on various targets, and among them ion channels and neurotransmitters. Moreover, they can operate as signaling metabolites and epigenetic modulators. Therefore, it is inappropriate to consider that the KD regimen can improve the patients' clinical condition simply by means of specific and localized effects; rather, it is more correct to think that KBs affect the organism as a whole. In this review, we tried to summarize the recent knowledge of the effects of KBs on various tissues, with a particular attention on the excitable ones, namely the nervous system, heart, and muscles.

QTc Prolongation in Pediatric Patients with Diabetic Ketoacidosis

OBJECTIVE

To investigate the association between diabetic ketoacidosis (DKA) and prolonged QTc interval and to assess for correlation between DKA severity and QTc prolongation.

STUDY DESIGN

Retrospective observational study in a pediatric hospital. Patients admitted with DKA diagnosed by laboratory criteria and an electrocardiogram (ECG) performed during a period of acidosis were identified using Looking Glass Clinical Analytics. Data including age, sex, pH, electrolytes, anion gap, and ECG variables were collected. Patients were excluded if they had a prior diagnosis of prolonged QTc or were taking QTc prolonging medications. Severity of DKA was classified as mild (pH 7.24-7.3), moderate (pH 7-7.24), or severe (pH <7). ECGs were read by a pediatric electrophysiologist and QTc interval was manually calculated utilizing the Bazett formula.

RESULTS

Ninety-six patients were included (mean age 15.2 ± 4.2 years, pH 7.12 ± 0.12, bicarbonate 8.6 ± 3.7 mmol/L, potassium 5.3 ± 1.1 mEq/L). Mean QTc interval for all patients in DKA was 454 ± 32 msec. Mean QTc in the mild group was 441 ± 22 msec, moderate group 460 ± 36 msec, and severe group 461 ± 34 msec. There was a significant difference in QTc interval across DKA severity groups (P = .05). There was a significant association between higher anion gaps and greater QTc intervals (r = 0.21, P = .04).

CONCLUSIONS

Thirty-one percent of pediatric patients with DKA demonstrated QTc prolongation on ECG. Severity of DKA and worsening acidosis were associated with increased prolongation of the QTc. Further study is required to evaluate the clinical impact of these findings.

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.

The ketogenic diet and the QT interval

Long QT syndrome is a disorder of ventricular myocardial repolarization associated with an increased risk of life-threatening cardiac arrhythmias and sudden cardiac death. This report highlights a case of QT prolongation with torsades de pointes in a patient with baseline congenital long QT syndrome, believed to be precipitated by metabolic changes associated with the "ketogenic diet."