Cardiac autonomic function in children with type 1 diabetes

Evaluation of cardiac autonomic dysfunctions in children with type 1 diabetes mellitus

BACKGROUND

Cardiovascular autonomic neuropathy (CAN) is a serious complication of diabetes, impacting the autonomic nerves that regulate the heart and blood vessels. Timely recognition and treatment of CAN are crucial in averting the onset of cardiovascular complications. Both clinically apparent autonomic neuropathy and subclinical autonomic neuropathy, particularly CAN pose a significant risk of morbidity and mortality in children with type 1 diabetes mellitus (T1DM). Notably, CAN can progress silently before manifesting clinically. In our study, we assessed patients with poor metabolic control, without symptoms, following the ISPAD 2022 guideline. The objective is is to determine which parameters we can use to diagnose CAN in the subclinical period.

METHODS

Our study is a cross-sectional case-control study that includes 30 children diagnosed with T1DM exhibiting poor metabolic control (average HbA1c > 8.5% for at least 1 year) according to the ISPAD 2022 Consensus Guide. These patients, who are under the care of the pediatric diabetes clinic, underwent evaluation through four noninvasive autonomic tests: echocardiography, 24-h Holter ECG for heart rate variability (HRV), cardiopulmonary exercise test, and tilt table test.

RESULTS

The average age of the patients was 13.73 ± 1.96 years, the average diabetes duration was 8 ± 3.66 years, and the 1-year average HbA1c value was 11.34 ± 21%. In our asymptomatic and poorly metabolically controlled patient group, we found a decrease in HRV values, the presence of postural hypotension with the tilt table test, and a decrease in ventricular diastolic functions that are consistent with the presence of CAN. Despite CAN, the systolic functions of the ventricles were preserved, and the dimensions of the cardiac chambers and cardiopulmonary exercise test were normal.

CONCLUSIONS

CAN is a common complication of T1DM, often associated with the patient's age and poor glycemic control. HRV, active orthostatic tests, and the evaluation of diastolic dysfunctions play significant roles in the comprehensive assessment of CAN. These diagnostic measures are valuable tools in identifying autonomic dysfunction at an early stage, allowing for timely intervention and management to mitigate the impact of cardiovascular complications associated with T1DM.

Lower left atrial function in young individuals with type 1 diabetes mellitus compared to healthy controls: an echocardiographic study

In adulthood, individuals with type 1 diabetes mellitus may develop a condition of heart failure with preserved ejection fraction. However, subclinical changes to the heart in diabetes are likely to occur prior to the clinical presentation. This cross-sectional study aimed to compare left atrial function by echocardiography between 43 individuals with type 1 diabetes and 43 healthy controls, aged 10-30 years. All participants underwent echocardiography and 2D speckle tracking measurements for left atrial phase function parameters. Physical capacity was assessed by exercise test on a bicycle. Results showed that participants with type 1 diabetes had significantly lower left atrial function parameters than healthy controls (p < 0.05). There was a significant negative correlation between HbA1c means and reservoir and conduit strain (p < 0.05) and individuals with BMI < 30 showed a lower left atrial stiffness (p < 0.05). Individuals with type 1 diabetes and a higher physical capacity did not differ from their healthy peers. Results indicate that lower HbA1c levels, BMI < 30 and a higher physical capacity are favourable in terms of left atrial function in children and young adults with type 1 diabetes mellitus. Left atrial strain by echocardiography might become a new important tool in assessing heart function in T1DM.

Screening for Gastric Sensory Motor Abnormalities in Pediatric Patients With Type 1 Diabetes

OBJECTIVE

To determine the frequency of gastric sensory motor symptoms in youth with type 1 diabetes.

METHODS

A prospective cross-sectional study was performed to evaluate symptoms of delayed gastric emptying in participants with type 1 diabetes, aged 12 to 25 years, using the Gastroparesis Cardinal Symptom Index (GCSI) questionnaire. In addition, a 5-year (January 2015 to December 2019), a retrospective study was completed on all gastric emptying scans performed in youth at our institution.

RESULTS

A total of 359 participants (mean age, 17.7 ± 3.33 years) with type 1 diabetes completed the GCSI questionnaire. Compared with nonresponders, responders were more likely to be non-Hispanic White (90% vs 86%; P =.003) and female patients (58% vs 44%; P <.0001), with a lower HbA1c (8.1 ± 1.8 vs 9.0 ± 2.1; P <.0001). At least 1 gastrointestinal symptom was reported in 270 (75%) of responders, of which nausea was the most common (71%). A GCSI score of ≥1.9 suggestive of more severe gastrointestinal symptoms was reported in 17% of responders. Participants with scores ≥1.9 were older (19.1 ± 3.0 vs 17.8 ± 3.3 years; P =.01). In the retrospective study, 778 underwent gastric emptying scan, 29 participants had type 1 diabetes and 11 (38%) showed delayed gastric emptying.

CONCLUSION

Gastrointestinal symptoms related to gastric sensory motor abnormalities are seen in youth and young adults with type 1 diabetes. In particular, for those with higher GCSI scores, earlier recognition and referral may be warranted.

A Review on Autonomic Functional Assessment in Diabetic Patients

In today's world, science has progressed significantly, yet most people are still unaware of diabetes. Lack of obesity, physical work, and lifestyle changes are the main factors. Diabetes is becoming more common all around the globe. Type 2 diabetes may go unnoticed for years, resulting in serious consequences and high healthcare expenses. The goal of this study is to look at a wide range of studies in which the autonomic function of diabetic people has been studied with the help of various autonomic function tests (AFTs). AFT is a non-invasive approach to assessing patients for testing sympathetic and parasympathetic responses to stimuli. AFT findings give us comprehensive knowledge of the autonomic physiology reactions in normal and in autonomic diseases like diabetes. This review will concentrate on AFTs that are scientifically valid, trustworthy, and clinically beneficial, according to experts.

Comprehensive cardiac evaluation to maximal exercise in a contemporary population of prepubertal children

BACKGROUND

Heart rate (HR) is a biomarker used to measure physiological function, health status and cardiovascular autonomic function. The purpose of this study was to determine sex- and age-specific reference values for cardiac autonomic function at rest, during maximal exercise and the recovery phase in prepubertal children.

METHODS

Five hundred and twelve healthy children 7-11 years of age performed a Léger test. A heart RR-interval monitor recorded the heart data and a specific software analysed the cardiac autonomic response through HR and HR variability (HRV). It analysed HR before the test (resting HR, RHR), during the test (HR_peak) and HR recovery (HRR) in the first minute (HRR1) and the fifth minute (HRR5). The values are mean ± SD.

RESULTS

Collectively, 91.2% of girls and 92.3% of boys were within the recommended ranges regarding RHR. The average HR_peak was 199 ± 10.83 b.p.m. and 96.8% of girls and 95.3% of boys were within the minimum threshold value recommended (180 b.p.m.). Boys showed lower values of RHR than girls (p < 0.001) and larger values of HRR 1 and HRR5 (p < 0.001).

CONCLUSIONS

This study comprehensively provides a reference set of data for the most important HR variables that can be obtained during exercise testing in prepubertal children regarding age and sex and in a field setting.

IMPACT

This is the first study to provide reference values of autonomic cardiac function at rest, during maximal exercise and during the recovery period in prepubertal children aged 7-11 years. Despite the early age of participants, cardiorespiratory fitness, RHR and HRR are different according to sex. Aerobic performance and HR_peak have a negative correlation with body mass index and cardiometabolic risk.

The Potential of Current Noninvasive Wearable Technology for the Monitoring of Physiological Signals in the Management of Type 1 Diabetes: Literature Survey

Background

Monitoring glucose and other parameters in persons with type 1 diabetes (T1D) can enhance acute glycemic management and the diagnosis of long-term complications of the disease. For most persons living with T1D, the determination of insulin delivery is based on a single measured parameter—glucose. To date, wearable sensors exist that enable the seamless, noninvasive, and low-cost monitoring of multiple physiological parameters.

Objective

The objective of this literature survey is to explore whether some of the physiological parameters that can be monitored with noninvasive, wearable sensors may be used to enhance T1D management.

Methods

A list of physiological parameters, which can be monitored by using wearable sensors available in 2020, was compiled by a thorough review of the devices available in the market. A literature survey was performed using search terms related to T1D combined with the identified physiological parameters. The selected publications were restricted to human studies, which had at least their abstracts available. The PubMed and Scopus databases were interrogated. In total, 77 articles were retained and analyzed based on the following two axes: the reported relations between these parameters and T1D, which were found by comparing persons with T1D and healthy control participants, and the potential areas for T1D enhancement via the further analysis of the found relationships in studies working within T1D cohorts.

Results

On the basis of our search methodology, 626 articles were returned, and after applying our exclusion criteria, 77 (12.3%) articles were retained. Physiological parameters with potential for monitoring by using noninvasive wearable devices in persons with T1D included those related to cardiac autonomic function, cardiorespiratory control balance and fitness, sudomotor function, and skin temperature. Cardiac autonomic function measures, particularly the indices of heart rate and heart rate variability, have been shown to be valuable in diagnosing and monitoring cardiac autonomic neuropathy and, potentially, predicting and detecting hypoglycemia. All identified physiological parameters were shown to be associated with some aspects of diabetes complications, such as retinopathy, neuropathy, and nephropathy, as well as macrovascular disease, with capacity for early risk prediction. However, although they can be monitored by available wearable sensors, most studies have yet to adopt them, as opposed to using more conventional devices.

Conclusions

Wearable sensors have the potential to augment T1D sensing with additional, informative biomarkers, which can be monitored noninvasively, seamlessly, and continuously. However, significant challenges associated with measurement accuracy, removal of noise and motion artifacts, and smart decision-making exist. Consequently, research should focus on harvesting the information hidden in the complex data generated by wearable sensors and on developing models and smart decision strategies to optimize the incorporation of these novel inputs into T1D interventions.

A systematic review of the prevalence, risk factors and screening tools for autonomic and diabetic peripheral neuropathy in children, adolescents and young adults with type 1 diabetes

AIMS

We aimed to estimate the prevalence of Diabetic peripheral neuropathy (DPN) and Cardiac autonomic neuropathy (CAN) in youth with type 1 diabetes; identify key risk factors; identify the most useful tests for the diagnostic evaluation of DPN and CAN; identify key treatment options for DPN and CAN.

METHODS

A systematic search was performed including studies published in the last 15 years. PICO framework was used in the selection process and evidence was assessed using the GRADE system.

RESULTS

A total of 758 studies were identified and a final number of 49 studies were included in this systematic review. According to moderate-high level quality studies, the prevalence of probable DPN, ranged between 13.5 and 62%; subclinical DPN between 22 and 88%; confirmed DPN between 2.6 and 11%. The Michigan Neuropathy Screening Instrument was the tool with higher sensitivity and specificity for detecting DPN, which needs to be confirmed by nerve conduction velocity. The prevalence of CAN was 4-39%. Specific treatment options for DPN or CAN in patients younger than 25 years are not available. Key risk factors for DPN and CAN are hyperglycemia/HbA1c, age, diabetes duration, the presence of other microvascular complications, waist/height ratio, lipid profile and blood pressure. For CAN, additional risk factors were cigarette smoking, BMI and total daily insulin.

CONCLUSIONS

Prevalence of neuropathy in youth with type 1 diabetes varies depending on different screening methods and characteristics of the study populations. However, the assessed studies confirmed a relatively high prevalence of subclinical neuropathy, reiterating the importance of early identification of risk factors to prevent this complication.

Heart Rate Variability Analysis to Evaluate Autonomic Nervous System Maturation in Neonates: An Expert Opinion

While heart rate variability (HRV) is a relevant non-invasive tool to assess the autonomic nervous system (ANS) functioning with recognized diagnostic and therapeutic implications, the lack of knowledge on its interest in neonatal medicine is certain. This review aims to briefly describe the algorithms used to decompose variations in the length of the RR interval and better understand the physiological autonomic maturation data of the newborn. Assessing newborns' autonomous reactivity can identify dysautonomia situations and discriminate children with a high risk of life-threatening events, which should benefit from cardiorespiratory monitoring at home. Targeted monitoring of HRV should provide an objective reflection of the newborn's intrinsic capacity for cardiorespiratory self-regulation.

Disturbances in the intraventricular conduction system in teenagers with type 1 diabetes. A pilot study

Body Surface Potential Mapping (BSPM) is a multi-electrode synchronous method for examining electrocardiographic records on the patients' body surface that allows the assessment of changes in the heart conduction system. The aim of the study was to visualize and evaluate changes in the intraventricular system in adolescents with T1D.

PATIENTS AND METHODS

Inclusion criteria: age > 12 years, T1D duration >3 years, HbA1c >8%.

EXCLUSION CRITERIA

diagnosis of autonomic neuropathy, heart structural defects, heart failure. BSPM data were processed into map plotting to illustrate differences in ventricular activation time (VAT, isochron lines).

RESULTS

33 teenagers (20 boys), mean age 15.0 ± 2.1 years, T1D from 6.8 ± 4.1 years were included. Mean HbA1c was 9.6 ± 2.0%. In the standard ECG recording abnormalities were not present. The distribution of isolines on the group-mean map plotted for T1D patients only initially resembles the course of isolines on the group-map for normal subjects (N = 30), in whom the electrical impulse stimulating the heart ventricles passes through the atrio-ventricular node, then symmetrically excites the branches of His bundle and finally the Purkinje fibers. In T1D patients, after proper onset of intraventricular stimulation, the isolines reflecting the both ventricles reach higher time values, which indicates problems in the propagation of the ventricular depolarization.

Corneal confocal microscopy identifies a reduction in corneal keratocyte density and sub-basal nerves in children with type 1 diabetes mellitus

PURPOSE

To assess whether alterations in stromal keratocyte density are related to loss of corneal nerve fibres in children with type 1 diabetes mellitus (T1DM).

METHODS

Twenty participants with T1DM and 20 age-matched healthy controls underwent corneal confocal microscopy. Corneal sub-basal nerve morphology and corneal keratocyte density (KD) were quantified.

RESULTS

Corneal nerve fibre density (CNFD) (p<0.001), corneal nerve branch density (p<0.001), corneal nerve fibre length (CNFL) (p<0.001) and inferior whorl length (IWL) (p<0.001) were lower in children with T1DM compared with healthy controls. Anterior (p<0.03) and mid (p=0.03) stromal KDs were lower with no difference in posterior KD (PKD) in children with T1DM compared with controls. Age, duration of diabetes, height, weight and body mass index did not correlate with anterior (AKD), mid (MKD) or PKD. Inverse correlations were found between glycated haemoglobin and PKD (r=-0.539, p=0.026), bilirubin with MKD (r=-0.540, p=0.025) and PKD (r=-0.531, p=0.028) and 25-hydroxycholecalciferol with MKD (r=-0.583, p=0.018). CNFD, CNFL and IWL did not correlate with AKD, MKD or PKD.

CONCLUSION

This study demonstrates a reduction in corneal nerves and anterior and mid stromal KD in children with T1DM, but no correlation between corneal nerve and keratocyte cell loss.

Diabetic neuropathy in children and youth: New and emerging risk factors

Pediatric neuropathy attributed to metabolic dysfunction is a well-known complication in children and youth with type 1 diabetes. Moreover, the rise of obesity and in particular of type 2 diabetes may cause an uptick in pediatric neuropathy incidence. However, despite the anticipated increase in neuropathy incidence, pathogenic insights and strategies to prevent or manage neuropathy in the setting of diabetes and obesity in children and youth remain unknown. Data from adult studies and available youth cohort studies are providing an initial understanding of potential diagnostic, management, and preventative measures in early life. This review discusses the current state of knowledge emanating from these efforts, with particular emphasis on the prevalence, clinical presentation, diagnostic approaches and considerations, and risk factors of neuropathy in type 1 and type 2 diabetes in children and youth. Also highlighted are current management strategies and recommendations for neuropathy in children and youth with diabetes. This knowledge, along with continued and sustained emphasis on identifying and eliminating modifiable risk factors, completing randomized controlled trials to assess effectiveness of strategies like weight loss and exercise, and enhancing awareness to support early detection and prevention, are pertinent to addressing the rising incidence of neuropathy associated with diabetes and obesity in children and youth.

Updating the Risk Stratification for Sudden Cardiac Death in Cardiomyopathies: The Evolving Role of Cardiac Magnetic Resonance Imaging. An Approach for the Electrophysiologist

The prevention of sudden cardiac death (SCD) in cardiomyopathies (CM) remains a challenge. The current guidelines still favor the implantation of devices for the primary prevention of SCD only in patients with severely reduced left ventricular ejection fraction (LVEF) and heart failure (HF) symptoms. The implantation of an implantable cardioverter-defibrillator (ICD) is a protective barrier against arrhythmic events in CMs, but the benefit does not outweigh the cost in low risk patients. The identification of high risk patients is the key to an individualized prevention strategy. Cardiac magnetic resonance (CMR) provides reliable and reproducible information about biventricular function and tissue characterization. Furthermore, late gadolinium enhancement (LGE) quantification and pattern of distribution, as well as abnormal T1 mapping and extracellular volume (ECV), representing indices of diffuse fibrosis, can enhance our ability to detect high risk patients. CMR can also complement electro-anatomical mapping (EAM), a technique already applied in the risk evaluation and in the ventricular arrhythmias ablation therapy of CM patients, providing a more accurate assessment of fibrosis and arrhythmic corridors. As a result, CMR provides a new insight into the pathological substrate of CM. CMR may help identify high risk CM patients and, combined with EAM, can provide an integrated evaluation of scar and arrhythmic corridors in the ablative therapy of ventricular arrhythmias.

Corneal nerve loss in children with type 1 diabetes mellitus without retinopathy or microalbuminuria

Aims/Introduction

Corneal confocal microscopy is a rapid, non‐invasive ophthalmic technique to identify subclinical neuropathy. The aim of this study was to quantify corneal nerve morphology in children with type 1 diabetes mellitus compared with age‐matched healthy controls using corneal confocal microscopy.

Materials and Methods

A total of 20 participants with type 1 diabetes mellitus (age 14 ± 2 years, diabetes duration 4.08 ± 2.91 years, glycated hemoglobin 9.3 ± 2.1%) without retinopathy or microalbuminuria and 20 healthy controls were recruited from outpatient clinics. Corneal confocal microscopy was undertaken, and corneal nerve fiber density (n/mm²), corneal nerve branch density (n/mm²), corneal nerve fiber length (mm/mm²), corneal nerve fiber tortuosity and inferior whorl length (mm/mm²) were quantified manually.

Results

Corneal nerve fiber density (22.73 ± 8.84 vs 32.92 ± 8.59; P < 0.001), corneal nerve branch density (26.19 ± 14.64 vs 47.34 ± 20.01; P < 0.001), corneal nerve fiber length (13.26 ± 4.06 vs 19.52 ± 4.54; P < 0.001) and inferior whorl length (15.50 ± 5.48 vs 23.42 ± 3.94; P < 0.0001) were significantly lower, whereas corneal nerve fiber tortuosity (14.88 ± 5.28 vs 13.52 ± 3.01; P = 0.323) did not differ between children with type 1 diabetes mellitus and controls. Glycated hemoglobin correlated with corneal nerve fiber tortuosity (P < 0.006) and aspartate aminotransferase correlated with corneal nerve fiber density (P = 0.039), corneal nerve branch density (P = 0.003) and corneal nerve fiber length (P = 0.037).

Conclusion

Corneal confocal microscopy identifies significant subclinical corneal nerve loss, especially in the inferior whorl of children with type 1 diabetes mellitus without retinopathy or microalbuminuria.

Sodium glucose co-transporter 2 inhibition reduces succinate levels in diabetic mice

BACKGROUND

Type 1 diabetes (T1D) is associated with major chronic microvascular complications which contribute significantly to diabetes associated morbidity. The protein primarily responsible for glucose reabsorption in the kidney is sodium glucose co-transporter 2 (SGLT2). Presently, SGLT2 inhibitors are widely used in diabetic patients to improve blood glucose levels and prevent cardiovascular and renal complications. Given the broad therapeutic application of SGLT2 inhibitors, we hypothesised that SGLT2 inhibition may exert its protective effects via alterations of the gut microbiome and tested this in a type 1 diabetic mouse model of diabetic retinopathy.

AIM

To determine whether the treatment with two independent SGLT2 inhibitors affects gut health in a type 1 diabetic mouse model.

METHODS

The SGLT2 inhibitors empagliflozin or dapagliflozin (25 mg/kg/d) or vehicle dimethylsulfoxide (DMSO) were administered to C57BL/6J, Akita, Kimba and Akimba mice at 10 wk of age for 8 wk via their drinking water. Serum samples were collected and the concentration of succinate and the short chain fatty acid (SCFA) butyric acid was measured using gas chromatography-mass spectrometry. Enzyme-linked immunosorbent assay (ELISA) was performed to determine the concentration of insulin and leptin. Furthermore, the norepinephrine content in kidney tissue was determined using ELISA. Pancreatic tissue was collected and stained with haematoxylin and eosin and analysed using brightfield microscopy.

RESULTS

Due to the presence of the Akita allele, both Akita and Akimba mice showed a reduction in insulin production compared to C57BL/6J and Kimba mice. Furthermore, Akita mice also showed the presence of apoptotic bodies within the pancreatic islets. The acinar cells of Akita and Akimba mice showed swelling which is indicative of acute injury or pancreatitis. After 8 wk of SGLT2 inhibition with dapagliflozin, the intermediate metabolite of gut metabolism known as succinate was significantly reduced in Akimba mice when compared to DMSO treated mice. In addition, empagliflozin resulted in suppression of succinate levels in Akimba mice. The beneficial SCFA known as butyric acid was significantly increased in Akita mice after treatment with dapagliflozin when compared to vehicle treated mice. The norepinephrine content in the kidney was significantly reduced with both dapagliflozin and empagliflozin therapy in Akita mice and was significantly reduced in Akimba mice treated with empagliflozin. In non-diabetic C57BL/6J and Kimba mice, serum leptin levels were significantly reduced after dapagliflozin therapy.

CONCLUSION

The inhibition of SGLT2 reduces the intermediate metabolite succinate, increases SCFA butyric acid levels and reduces norepinephrine content in mouse models of T1D. Collectively, these improvements may represent an important mechanism underlying the potential benefits of SGLT2 inhibition in T1D and its complications.

Autonomic maturation from birth to 2 years: normative values

Background

While heart rate variability (HRV) constitutes a relevant non-invasive tool to assess the autonomic nervous system (ANS) function with recognized diagnostic or therapeutic implications, there is still a lack of established data on maturation of autonomic control of heart rate during the first months of life. The Autonomic Baby Evaluation (AuBE) cohort was built to establish, the normal autonomic maturation profile from birth up to 2 years, in a healthy population of full-term newborns.

Methods

Heart rate variability analysis was carried out in 271 full-term newborns (mean gestational age 39 wGA + 5 days) from reliable polysomnographic recordings at 0 (n = 270) and 6 (n = 221) months and from a 24-hour ambulatory electrocardiogram (ECG) at 12 (n = 210), 18 (n = 197), and 24 (n = 190) months. Indices of HRV analysis were calculated through the ANSLabTools software.

Results

Indices are dissociated according a temporal, geometrical, frequency, Poincaré, empirical mode decomposition, fractal, Chaos and DC/AC and entropy analysis. Each index is presented for five different periods of time, 0, 6, 12, 18 and 24 months and with smoothed values in the 3rd, 10th, 50th, 90th and 97th percentiles. Data are also presented for the full cohort and individualized by sex to account for gender variability.

Discussion & conclusion

The physiological autonomic maturation profile from birth to 2 years in a healthy population of term neonates results in a fine-tuning autonomic maturation underlying progressively a new equilibrium and privileging the parasympathetic activity over the sympathetic activity.

FUNCTIONAL CONDITION OF THE CARDIOVASCULAR SYSTEM IN CHILDREN WITH TYPE 1 DIABETES DEPENDING ON THE LEVEL OF GLYCEMIA

Purpose of the study: to determine main parameters of the heart rhythm in children with type 1 diabetes, depending on the night level of glycemia. We performed bifunctional monitoring of glycemia and ECG in 50 patients with type 1 diabetes from 10 to 17 years. Depending on the glycemic parameters summarized in all patients we divided 3 groups: Group 1 (n=11) – sites of hypoglycemia (≤3.9 mmol/l), Group 2 (n=35) – optimal level of glycemia (4.0-9.0 mmol/l) and Group 3 (n=45) – sites of hyperglycemia (> 9 mmol/l). According to the results of glycemic monitoring, 96% of children do not have glycemic target marks at night and 20% of patients have asymptomatic night hypoglycemia. When analyzing the parameters of Holter ECG monitoring, the greatest value of heart rate, duration of the QTc interval, as well as atrial ectopic activity were often recorded during periods of hypoglycemia. Hyperglycemia also causes pathologic elongation of the ventricular electric systole and a greater number of ventricular extrasystoles. Thus, night hypo- and hyperglycemia in children and adolescents with type 1 diabetes leads to an extension of the QTc interval, an increase in the number of extrasystoles with the highest severity and frequency in hypoglycemia. We noted a high level of functioning of the sympathetic department of the autonomic nervous system and the central contour of heart rhythm regulation in children and adolescents with type 1 diabetes mellitus in hypoglycemia.

Prospects of using cardiovascular magnetic resonance in the identification of arrhythmogenic substrate in autoimmune rheumatic diseases

Sudden cardiac death (SCD) is due to ventricular tachycardia/fibrillation (VT/VF) and may occur with or without any structural or functional heart disease. The presence of myocardial edema, ischemia and/or fibrosis plays a crucial role in the pathogenesis of VT/VF, irrespective of the pathophysiologic background of the disease. Specifically, in autoimmune rheumatic diseases (ARDs), various entities such as myocardial/vascular inflammation, ischemia and fibrosis may lead to VT/VF. Furthermore, autonomic dysfunction, commonly found in ARDs, may also contribute to SCD in these patients. The only non-invasive, radiation-free imaging modality that can perform functional assessment and tissue characterization is cardiovascular magnetic resonance (CMR). Due to its capability to detect and quantify edema, ischemia and fibrosis in parallel with ventricular function assessment, CMR has the great potential to identify ARD patients at high risk for VT/VF, thus influencing both cardiac and anti-rheumatic treatment and modifying perhaps the criteria for implantation of cardioverter defibrillators.