Introduction: The suppression of tumorigenicity 2 (ST2) is a receptor member belonging to the interleukin-1 (IL-1) family. The ligand and soluble versions are its two isoforms. The IL-33-ST2L ligand complex’s development provides protection against heart fibrosis and hypertrophy. Investigations on heart failure in adults have demonstrated that it does not change by age, body mass index (BMI), creatinine, hemoglobin, and albumin levels, in contrast to NT pro BNP. In adult heart failure patients, it has been demonstrated to be an independent predictor of mortality and cardiovascular events. The most recent guideline recommends using it as class 2b in the diagnosis of adult heart failure. Studies on ST2 in children are rare. The purpose of this study is to assess the prognostic value of ST2 for cardiovascular events in young individuals suffering from heart failure. Method: This study included pediatric patients (0–18 years old) with congenital heart disease or cardiomyopathy who needed medical care, as well as surgical or interventional treatment. Height, weight, gender, saturation, heart failure classification (Ross or NYHA), medications, the electrocardiogram, echocardiography, pro BNP, and sST2 values of the patients, as well as any hospitalization, lower respiratory tract infection, organ dysfunction, or need for angiography or surgery during follow-up data on arrhythmia and death were gathered during a 1-year follow-up. The SPSS software version 25 application was used to carry out the statistical analysis. Results: This study included 59 patients, of whom 27 (46.6%) were male. The average age of the patients was 55.5 months (1–228 months) and the average body weight was 16 kg (2.6–90 kg). Major cardiovascular events occurred in 45 of 59 patients (76.3%). Twenty-four patients experienced one MACE, while twenty-one patients experienced multiple MACEs. Pro BNP and sST2 levels were similar in the groups that developed MACE compared to those that did not. Pro BNP was discovered to be significantly higher in patients with hospitalization, growth retardation, lower respiratory tract infection, and organ failure, however, when assessing each situation (p = 0.001, p = 0.011, p = 0.001, p = 0.007, respectively). Soluble ST2 was found to be higher in patients with growth retardation than in those without (p = 0.037). Although the soluble ST2 level failed to demonstrate a correlation with pro BNP, it did show a positive correlation (r = 0.437) with the Ross score. When compared to other groups, it was discovered to be higher in patients with valvular insufficiency type heart disease. Conclusions: In this study, higher sST2 levels were discovered, particularly in the group with valve insufficiency and children with growth retardation. It was associated with the Ross score, but not with the pro BNP level. Although it increases in correlation with clinical heart failure, its predictive value for MACE is low. Similarly, pro BNP is not proven to be predictive; nonetheless, its high levels in patients with hospitalization, growth retardation, lower respiratory tract infection, and organ failure demonstrate that pro BNP may increase for a variety of causes. Long-term studies with more patients are needed for ST2 to be suitable for clinical use in pediatric patients.

Introduction Carbon monoxide poisoning may cause myocardial toxicity and cardiac autonomic dysfunction, which may contribute to the development of life-threatening arrhythmias. We investigated the potential association between acute carbon monoxide exposure and cardiac autonomic function measured by heart rate variability. Method The present study included 40 children aged 1–17 years who were admitted to the Pediatric Intensive Care Unit with acute carbon monoxide poisoning and 40 healthy age- and sex-matched controls. Carboxyhaemoglobin and cardiac enzymes were measured at admission. Electrocardiography was performed on admission and discharge, and 24-hour Holter electrocardiography was digitally recorded. Heart rate variability was analysed at both time points – 24-hour recordings – and frequency domains – from the first 5 minutes of intensive care unit admission. Results Time domain and frequency indices such as high-frequency spectral power and low-frequency spectral power were similar between patient and control groups (p>0.05). The ratio of low-frequency spectral power to high-frequency spectral power was significantly lower in the carbon monoxide poisoning group (p<0.001) and was negatively correlated with carboxyhaemoglobin levels (r=−0.351, p<0.05). The mean heart rate, QT dispersion, corrected QT dispersion, and P dispersion values were higher in the carbon monoxide poisoning group (p<0.05) on admission. The QT dispersion and corrected QT dispersion remained longer in the carbon monoxide poisoning group compared with controls on discharge (p<0.05). Conclusion The frequency domain indices, especially the ratio of low-frequency spectral power to high-frequency spectral power, are useful for the evaluation of the cardiac autonomic function. The decreased low-frequency spectral power-to-high-frequency spectral power ratio reflects a balance of the autonomic nervous system, which shifted to parasympathetic components.

Mitochondrial defects can lead to cardiomyopathies, which can be particularly severe in children. However, many cases of pediatric cardiomyopathy have no known etiology. To address this, we sought to explore if mitochondrial genome defects might be a contributor, as this could offer insights into disease mechanisms and guide targeted interventions. We first sequenced cardiomyopathy-related genes in twenty-seven pediatric patients diagnosed with primary non-syndromic cardiomyopathy and performed whole mtDNA sequencing in both patients and thirty-one healthy controls. The initial sequencing identified pathogenic variants in seven patients but subsequent mtDNA sequencing revealed additional insights. Specifically, a variant in FOXRED1, encoding FAD-dependent oxidoreductase domain-containing protein-1 which functions in mitochondrial complex I stability, and another variant in cytochrome c oxidase-I, MT-CO1, crucial for aerobic metabolism, were identified in two siblings with hypertrophic cardiomyopathy. In another case with hypertrophic cardiomyopathy, a variant in cytochrome b, MT-CYB, is likely a key factor in the abnormal contraction of cardiac muscle contraction. Furthermore, a novel 12 S rRNA variant was found in a patient with left ventricular non-compaction, and this offers a promising explanation for the pathogenesis, given the gene’s high expression in the left ventricle. Taken together, mtDNA variants act synergistically with others, potentially disrupting myocardial bioenergetics.