Evaluation of electrocardiographic parameters for early diagnosis of autonomic dysfunction in children and adolescents with type-1 diabetes mellitus

Ventricular depolarization and repolarization variability in children with type 1 diabetes mellitus

BACKGROUND

Arrhythmias can be seen as a sign of cardiac autonomic neuropathy in type 1 diabetes mellitus. We aimed to evaluate pulmonary artery pressure, ventricular depolarization and repolarization variability in children with type 1 diabetes mellitus.

METHODS

We investigated 78 children with type 1 diabetes mellitus (mean age 11.6 ± 3.6 years) and 68 age-gender matched healthy children as control group. All type 1 diabetes mellitus patients were divided into three subgroups according to glycated hemoglobin (HbA1c) levels and the duration of disease. Electrocardiogram and transthoracic echocardiograms were performed on both groups.

RESULTS

In patients with type 1 diabetes mellitus, there was an elongation in P, Pd, PR, QTc, QTd, QTcd, JT, JTc, JTd, Tp-Te and Tp-Te/QT, Tp-Te/QTc, Tp-Te/JT, Tp-Te/JTc ratios were higher (P < 0.05). In patients with type 1 diabetes mellitus, pulmonary artery pressure was higher than control group (P = 0.001). Prolongation of QTc, thickness of left ventricle end-diastolic diameter and left ventricle posterior wall diameter were higher in the HbA1c ≥9% subgroup. When adjusted for age there was no significant correlation between left ventricle parameters and HbA1c.

CONCLUSIONS

Atrial conduction delay and impairment of ventricular repolarization were significantly high and there was a predisposition for the development of pulmonary artery hypertension in children with type 1 diabetes mellitus. Poor glycemic control was not a risk factor for propensity of left ventricle hypertrophy and left ventricle dysfunction.

Electrocardiographic data of children with type 1 diabetes mellitus

BACKGROUND

Adult patients diagnosed with type 1 diabetes mellitus are at risk for ventricular arrhythmias and sudden cardiac death.

AIM

The objective of our study is to evaluate the electrocardiographic data of children diagnosed with type 1 diabetes mellitus and to determine the possibility of arrhythmia in order to prevent sudden death.

METHODS

Electrocardiographic data of 60 patients diagnosed with type 1 diabetes mellitus and 86 controls, who were compatible with the patient group in terms of age and gender, were compared.

RESULTS

The duration of diabetes in our patients with type 1 diabetes mellitus was 5.23 ± 1.76 years, and the haemoglobin A1c levels were 9.63% ± 1.75%. The heart rate, QRS, QT maximum, QT dispersion, QTc minimum, QTc maximum, QTc dispersion, Tp-e maximum, Tp-e maximum/QTc maximum and the JTc were significantly higher compared to the control group. There was no significant correlation between the duration of type 1 diabetes mellitus and HbA1c levels and the electrocardiographic data.

CONCLUSION

We attributed the lack of a significant correlation between the duration of type 1 diabetes mellitus and the haemoglobin A1c levels and the electrocardiographic data to the fact that the duration of diabetes was short, since our patients were children. We believe that patients with type 1 diabetes mellitus should be followed up closely in terms of sudden death, as they have electrocardiographic changes that may cause arrhythmias compared to the control group. However, more studies with longer follow-up periods are necessary to support our data.

Electrocardiography Findings in Children with Febrile Convulsion

Febrile convulsion (FC) is a seizure associated with body temperature that leads to electrocardiography changes. This article aimed to study electrocardiographic changes in children with FC as compared with healthy children. In this case–control study, 90 children aged 6 to 60 months were matched with equal healthy ones in “Ali Ebne Abi Talib” hospital in Zahedan, Iran. FC was confirmed by a neurologist based on its definition by the International League Against Epilepsy. Electrocardiogram (ECG) was captured by a pediatric cardiologist. Data were analyzed using SPSS 19. Sex distribution in groups was similar (p = 0.232). QT correction (QTc) was normal in 97.8 and 76.7% of controls and FC children, respectively (p < 0.001). QT dispersion (QTd) was normal in all controls when it was prolonged in 0.6% of children (p< 0.316). Calculated QT (QTcd) prolonged in controls and FC of 4.4 and 27.8% of children, respectively (p < 0.001). RR interval (p = 0.001), heart rate (p< 0.001), S in V1 (p = 0.004), R in aVL (p = 0.007), S in V3(p< 0.001), left ventricular mass (LVM) (p< 0.001), QTd (p< 0.001), QTc max (p< 0.001), and QTcd (p< 0.001) were significant. Means of LVM were 46.00 ± 1.86, 47.22 ± 2.24, and 51.45 ± 2.41 for age groups of <12, 12–24, and >24 months, respectively (p < 0.001). We conclude that QTd, QTc, and QTcd were higher in FC compared with those of healthy children. The rate of FC in children with higher level of QTcd increased compared with controls.

The relationship between QT interval indices with cardiac autonomic neuropathy in diabetic patients: a case control study

BACKGROUND

Long QT interval (QT) and abnormal QT dispersion (QTd) are associated with sudden death. The relationship between cardiac autonomic neuropathy (CAN) and QT indices in type 2 diabetic patients were investigated.

METHODS

Totally 130 diabetic subjects (mean age 50.87 ± 13.9 years) were included (70 individuals with and 60 individuals without CAN). All participants had sinus cardiac rhythm. The patients who had diseases or take drugs that cause orthostatic hypotension (OH), cardiac arrhythmia and QT prolongation were excluded. After interview and examination, standard and continuous ECG was taken in supine position with deep breathing and standing up position. CAN diagnosis was based on Ewing's tests. QT, QT corrected (QTc), minimum QT (QT min), maximum QT (QT max) and mean ± SD of QT (QT mean) and QTd were assessed from standard ECG. QTc was calculated by Bazett's formula from V2 lead. QTc > 440 ms in men and QTc > 460 ms in women and QTd > 80 ms were considered abnormal.

RESULTS

In patients with CAN, 21.5% were symptomatic. The prevalence of abnormal QTc and QTd was 11.3% and 28.7%, respectively. There was no significant difference between the patients with or without CAN in terms of long QTc and abnormal QTd. However, the mean ± SD of QT max, QT mean and QTd was higher in the patients with CAN (P value < 0.03). The used cut points for QTc and QTd have high specificity (79% for both) and low sensitivity (30% and 37%, respectively). To use QTc and QTd as screening test for CAN in T2DM patients, the cutoff points 380 and 550 ms are suggested, respectively.

CONCLUSION

The prevalence of asymptomatic CAN was 3.7 times that of symptomatic CAN. In patients with CAN the QT max, QT mean and QTd were higher than those without CAN. There was no association between CAN and long QTc and abnormal QTd.

Early changes in myocyte contractility and cardiac function in streptozotocin-induced type 1 diabetes in rats

Diabetes can elicit direct deleterious effects on the myocardium, independent of coronary artery disease or hypertension. These cardiac disturbances are termed diabetic cardiomyopathy showing increased risk of heart failure with or without reduced ejection fraction. Presently, there is no specific treatment for this type of cardiomyopathy and in the case of type I diabetes, it may start in early childhood independent of glycemic control. We hypothesized that alterations in isolated myocyte contractility and cardiac function are present in the early stages of experimental diabetes in rats before overt changes in myocardium structure occur. Diabetes was induced by single-dose injection of streptozotocin (STZ) in rats with data collected from control and diabetic animals 3 weeks after injection. Left ventricle myocyte contractility was measured by single-cell length variation under electrical stimulation. Cardiac function and morphology were studied by high-resolution echocardiography with pulsed-wave tissue Doppler imaging (TDI) measurements and three-lead surface electrocardiogram. Triglycerides, cholesterol and liver enzyme levels were measured from plasma samples obtained from both groups. Myocardial collagen content and perivascular fibrosis of atria and ventricle were studied by histological analysis after picrosirius red staining. Diabetes resulted in altered contractility of isolated cardiac myocytes with increased contraction and relaxation time intervals. Echocardiography showed left atrium dilation, increased end-diastolic LV and posterior wall thickness, with reduced longitudinal systolic peak velocity (S’) of the septum mitral annulus at the apical four-chamber view obtained by TDI. Triglycerides, aspartate aminotransferase and alkaline phosphatase were elevated in diabetic animals. Intertitial collagen content was higher in atria of both groups and did not differ among control and diabetic animals. Perivascular intramyocardial arterioles collagen did not differ between groups. These results suggest that alterations in cardiac function are present in the early phase in this model of diabetes type 1 and occur before overt changes in myocardium structure appear as evaluated by intersticial collagen deposition and perivascular fibrosis of intramyocardial arterioles.

Evaluation of Electrocardiographic Ventricular Depolarization and Repolarization Variables in Type 1 Diabetes Mellitus

Background

The risk of cardiovascular events and sudden death increases with type 1 diabetes mellitus (T1DM).

Objective

To evaluate electrocardiographic markers of arrhythmias in T1DM patients.

Methods

Electrocardiographic parameters reflecting ventricular depolarization and repolarization, namely, QT, QTc, QTd, QTdc, Tp-e, JT, and JTc intervals and Tp-e/QT and Tp-e/QTc ratios, of 46 patients diagnosed with T1DM were retrospectively analyzed and compared with 46 healthy age-, sex-, and body mass-matched controls. Correlations between T1DM duration, hemoglobin A1c (HbA1c), and ventricular repolarization variables were analyzed. P values lower than 0.05 were considered statistically significant.

Results

Diabetes duration was 16.6 ± 7.1 years, and HbA1c was 10.81% ± 3.27% in the T1DM group. In comparison with the control group, heart rate, QTc, QTd, QTdc, Tp-e and JTc intervals, Tp-e/QT ratio (p < 0.001), and Tp-e/QTc ratio (p = 0.007) were significantly higher in T1DM patients. T1DM duration and HbA1c levels were significantly correlated with QTc, QTd, QTdc, Tp-e, and JTc intervals and Tp-e/QT and Tp-e/QTc ratios.

Conclusions

In T1DM patients, potential electrocardiographic repolarization predictors were significantly increased in correlation with disease duration and HbA1c levels. These findings may contribute to the understanding of sudden cardiac death in patients with T1DM.

Electrocardiographic changes in children with diabetic ketoacidosis and ketosis

Aim

We aimed to study electrocardiographic changes in children with diabetic ketoacidosis and ketosis and to evaluate the relation of the changes with serum electrolyte levels and ketosis.

Material and Methods

This study was performed in Istanbul Medical Faculty, Pediatric Emergency and Intensive Care Department between May 2008 and May 2009. The electrocardiographic parameters and QT length of children with diabetic ketoacidosis and ketosis were evaluated at diagnosis and after the treatment.

Results

Forty patients were included in the study; 16 (40%) were diagnosed as having diabetic ketosis and 24 (60%) had diabetic ketoacidosis. Twenty-four (60%) patients were male and 16 (40%) were female and the mean age was 9.21±4.71 years (range, 1-16 years). Twelve (30%) cases of diabetic ketoacidosis were mild, three (7.5%) were moderate, and nine (22.5%) were severe. One patient had premature ventricular beats, and four had ST depression. The electrocardiographic parameters were all normal beyond the QTC length prolongation. The mean QTC length was 447±45 ms (380-560 ms) at diagnosis and 418±32 ms (350-500 ms) after treatment. The change in the QTC length was statistically significant. None of the patients had significant electrolyte disturbance and the prolongation of QTc length was not correlated with serum electrolyte levels. The prolongation of QTc length was statistically correlated with anion gap (r=0.33, p=0.03).

Conclusions

In our study, we showed QTc length prolongation and the importance of performing electrocardiography during the diagnosis of diabetic ketoacidosis and ketosis. We also demonstrated that ketosis was responsible for the prolongation of QTc length.

Electrocardiography-Derived Predictors for Therapeutic Response to Treatment in Children with Postural Tachycardia Syndrome

OBJECTIVE

To explore whether electrocardiography (ECG) variables could be used to predict responses to physical treatment in children with postural tachycardia syndrome (POTS).

STUDY DESIGN

Forty children with POTS and 32 healthy controls were enrolled in this study. General information and hemodynamic and supine ECG variables, including QT interval dispersion (QTd), were collected. The children with POTS received physical treatment and 3 months of follow-up. A receiver-operating characteristic curve was used to evaluate the value of ECG variables for predicting the effectiveness of physical treatment.

RESULTS

Compared with the healthy children, the children with POTS had longer baseline QTd and heart rate (HR)-corrected QTd (QTcd), but shorter minimum QT intervals (QTmin) and minimum HR-corrected QT intervals (P < .05). In children with POTS, responders to physical treatment had a longer baseline time between QRS complexes (RR) interval of minimum QT interval and a longer QTcd compared with nonresponders. A longer QTcd was a significant risk factor for the presence of POTS (OR, 1.022; P = .02) and for undesirable responses to physical treatment in children with POTS (OR, 1.044; P = .03). Baseline QTcd was positively correlated with the HR elevation from supine to upright seen in children with POTS (r = 0.348; P = .003). Receiver operating characteristic curve analysis demonstrated an area under the curve of 0.73, and using 43.0 msec as a cutoff of QTcd yielded a sensitivity of 90% and a specificity of 60%.

CONCLUSION

QTcd might be useful for predicting the effectiveness of physical treatment for POTS in children.