Marina Olegovna Gulya

Introduction. ST segment changes can be observed both in completely healthy children and in children with organic myocardial pathology. Currently, there are no recommendations for the management of pediatric patients with documented ST segment changes on the ECG.Aim: To analyze clinical data, identify causes of ST segment changes on the ECG and determine diagnostic algorithms for treatment tactics.Material and Methods. The study included 22 patients with ST segment and T wave changes according to standard ECG. All patients underwent daily ECG monitoring, exercise stress test, standard Echo. Diagnostic laboratory screening included determination of lipid spectrum, electrolyte analysis (sodium, potassium, calcium), assessment of markers of myocardial damage and inflammation. In case of deviations, additionally MSCT coronary angiography, myocardial perfusion scintigraphy and stress echocardiography were performed.Results. 22 patients with ST segment changes on the ECG were examined. In two cases, the cause of ST segment changes was undifferentiated cardiomyopathy. Both patients were asymptomatic, one of them was an athlete. In eight cases, ST segment and T wave changes on the ECG were assessed as manifestations of autonomic dysfunction against the background of concomitant pathology. Anomalies of the course and development of the coronary arteries, including muscular bridges (MB) and anomalies of the origin of the coronary vessels, were detected in 12 examined patients, including two patients with WolffParkinson-White (WPW) syndrome and phenomenon, in whom ST segment changes persisted after radiofrequency ablation (RFA) and in three sportsmen. Based on the examination, one patient with an identified anomaly of the coronary arteries underwent surgical correction. Five patients were prescribed drug therapy with β-blockers.Conclusion. ST segment changes on the ECG require special attention. Standard ECG and echocardiography have limitations in diagnosing coronary artery anomalies. A mandatory method of additional examination is physical exercise tests. In case of suspicion of an ischemic nature of changes, it is extremely important to exclude coronary artery anomalies using additional examination methods, the most important of which is MSCT coronary angiography, invasive coronary angiography, myocardial perfusion scintigraphy, stress echocardiography are of auxiliary importance.

Heart failure is the leading cause of death, frequent hospitalizations, and poor quality of life. The fundamental mechanisms involved in the occurrence and progression of heart failure are currently not precisely defined. Mitochondria play a key role in the processes of cellular metabolism, performing many biological functions. The functional activity of mitochondria is inextricably linked to their structure. In cardiovascular diseases, in conditions of repeated hypoxia/reoxygenation of tissues, as well as under the influence of subclinical inflammation processes, pathological restructuring of the cardiomyocyte mitochondriome occurs. Studies conducted to date suggest that mitochondria may be the key to understanding the onset and progression of chronic heart failure (CHF). An analysis of the literature demonstrates that the study of mitochondria in patients with CHF is an urgent topic, and the number of publications in the PubMed/MEDLINE system concerning research in this area is progressively increasing, 100 publications on this topic have been found in the eLibrary system. In this review, we reviewed modern methods for evaluating the structure and function of mitochondria in experimental and clinical studies and analyzed the possibility of using these research methods in patients with cardiovascular diseases. It is shown that, despite a fairly wide range of possibilities for studying the structural and functional state of mitochondria of cardiomyocytes in CHF, the estimated indirect signs of mitochondrial dysfunction are surrogate markers, the degree of informativity of which must be studied in comparison with the actual state of the cardiomyocytes mitochondrial ultrastructure, the clinical picture of the disease and the prognosis of patients. The necessity of conducting clinical studies aimed at studying the association of direct ultrastructural characteristics of cardiomyocytes mitochondria with indirect signs of mitochondrial dysfunction with the clinical course and outcomes of CHF is actualized, which will allow us to obtain fundamentally new fundamental knowledge about the mechanisms of development and progression of the pathophysiological phenomenon of CHF, to assess the degree of informativeness of markers of mitochondrial dysfunction in patients with CHF, which will serve as the basis for the widespread introduction of these diagnostic methods into real clinical practice.

The article presents preliminary study results of association of direct ultrastructural characteristics of mitochondria (MTC) in cardiomyocytes and indirect signs of mitochondrial dysfunction with clinical course and outcomes of chronic heart failure (CHF). According to electron microscopy of the myocardium a violation of the ultrastructure of MTC of cardiomyocytes is accompanied by a decrease in the rate of oxygen absorption by mitochondria of leukocytes of peripheral blood, separation of oxidation and phosphorylation processes, an increased rate of radiopharmaceuticals leaching from myocardium, indicating mitochondrial membrane damage, low tolerance to physical load and reduced oxygen consumption at peak of load test, which confirms the feasibility of studying associations of indirect signs of mitochondrial dysfunction with ultrastructural changes in the mitochondrial cardiomyocytes and clinical manifestations of heart failure.

BACKGROUND: This review outlines the features of the pharmacokinetics of the perfusion radiopharmaceutical 99mTc-MIBI, which allows the assessment of myocardial mitochondrial dysfunction, and shows the main clinical applications of the phenomenon of increased 99mTc-MIBI washout rate. AIM: To systematize the data of fundamental (experimental) and clinical studies evaluating and estimating mitochondrial dysfunction according to myocardial perfusion scintigraphy data and perform meta-analysis of clinical studies in this field. MATERIALS AND METHODS: PubMed, Scopus, Google Scholar, and eLibrary databases were searched until mid-2023. The following keywords, their combinations, and Russian-language counterparts were used: mitochondrial dysfunction, 99mTc-MIBI, 99mTc-Tetrofosmin, myocardial perfusion scintigraphy, reverse redistribution, washout, and washout rate. In the meta-analysis, a random-effects model was used to calculate the mean difference estimate. RESULTS: Forty articles were selected for systematic analysis: 13 were experimental, 24 were original clinical papers, 2 were clinical cases, and 1 was a review. Six studies using a case–control design were selected for the meta-analyses. The total number of patients in the systematic review and meta-analysis were 551 and 196, respectively. In the analysis of the literature, the severity of the reverse redistribution phenomenon and 99mTc-MIBI washout rate correlated with mitochondrial and myocardial microstructure, left ventricular contractility and hemodynamics, natriuretic peptide levels, exercise tolerance, coronary atherosclerosis severity, myocardial oxidative metabolism, and risk of cardiovascular events. The meta-analysis showed that the washout rate was statistically significantly accelerated in individuals with cardiac pathologies, relative to controls (mean difference score, 9.5771 [95%]; confidence interval, 6.6001–12.5540; z=6.3053, p 0.0001). CONCLUSION: The assessment of mitochondrial function by 99mTc-MIBI washout evaluation may provide additional insights into the functional status of cardiac muscles.

X-ray computed tomography coronary angiography (CTCA) is a current method for diagnosing ischemic heart disease. Although this method has a high specificity and a negative predictive value in diagnosing coronary obstructions, there are limitations in determining the hemodynamic significance of the stenosis. Extensive use of noninvasive methods for evaluation of coronary hemodynamics, specifically evaluation of the fractional flow reserve (FFR) is limited due to its high cost and risks of complications. Mathematical modeling of coronary circulation and its reserve based on CTCA data is an up-to-date method that has been experimentally confirmed and clinically validated. This method showed a high diagnostic efficacy in several large studies that used the invasive determination of FFR as a “gold standard”. This review addresses the current state of studies on mathematical modeling for fractional coronary reserve in patients with ischemic heart disease, as well as the limitations and prospects of this method.

Aim. To reveal the association between disorders of myocardial blood flow and reserve, according to dynamic single photon emission computed tomography (SPECT), with risk factors for cardiovascular diseases (CVD) in patients with nonobstructive coronary artery disease (CAD).Material and methods. The study included patients with suspected stable nonobstructive (Results. The study included 47 patients divided into 2 following groups: the rMFR group consisted of 24 patients (15 men, age 56,3±9,1 years), the nMFR group — 23 patients (13 men, age 58,4±10,7 years). There was no significant difference in prevalence of CVD risk factors in groups. However, dyslipidemia was detected more often in rMFR patients (p=0,053): 58% vs 30%, respectively. In patients with rMFR, there were significantly higher levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Correlation analysis revealed significant negative inverse relationships between MFR values with TC (ρ=-0,36, p=0,01) and LDL-C (ρ=-0,38, p=0,009). According to univariate logistic regression, significant predictors of reduced MFR were TC (odds ratio (OR), 2,32; 95% confidence interval (CI), 1,17-4,59; p=0,01) and LDL-C (OR, 2,16; 95% CI, 1,04-4,51; p=0,04). According to a stepwise multivariate logistic regression analysis, only TC was an independent predictor of a decrease in MFR (OR, 2,32; 95% CI, 1,17-4,59; p=0,02).Conclusion. MFR, determined by dynamic SPECT, is associated with TC and LDL-C levels. TC level is an independent predictor of a decrease in MFR.

To evaluate the myocardial flow reserve (MFR) and myocardial blood flow (MBF) parameters in patients with heart failure with preserved ejection fraction (HFpEF) and to assess their relationship with the severity of HF and the levels of soluble ST2 (sST2). A total of 59 consecutive patients (median age of 65.0 (58.0; 69.0) years) with non-obstructive coronary artery disease (CAD) and preserved EF were enrolled. Serum levels biomarkers were measured by enzyme immunoassay. MBF and MFR parameters were evaluated by dynamic CZT-SPECT. All patients were divided into two groups: group 1 comprised patients (n = 41) with HFpEF, and group 2 comprised those (n = 18) without HFpEF. In group 1 global MFR (gMFR) values were lower by 27.8% (p = 0.003) than in group 2. The values of gMFR correlated with NT-proBNP (r = − 0.290) and sST2 (r = −0.331) levels. Based on ROC-analysis, gMFR ≤ 2.27 (AUC = 0.746; p < 0.001) were associated with the presence of HFpEF. In patients with HFpEF (n = 41) the values of gMFR were related to NYHA classes (p < 0.001) and the parameters of diastolic dysfunction (p < 0.001). The values of gMFR ≤ 2.27 may be used for the evaluation of microvascular changes in patients with HFpEF and non-obstructive CAD.

Modern imaging techniques occupy an important place in the diagnosis, selection of treatment and prognosis of patients with coronary artery disease. Hybrid imaging is a combination of two sets of diagnostic data that complement and enhance each other by comparing anatomical and functional characteristics. As a rule, hybrid imaging is synergistic, that is, more powerful, since the addition of new information leads to an increase in the sensitivity and specificity of each of the modalities separately.The review provides brief information on the diagnostic efficacy of myocardial perfusion scintigraphy (MPS), computerized tomography (CT) coronary angiography in comparison with invasive coronary angiography with fractional flow reserve. The diagnostic and prognostic significance of assessing calcium index with MPS, as well as CT coronary angiography combined with MPS in the diagnosis, risk stratification and prognosis of patients with coronary artery disease, is characterized in detail. A separate section is devoted to the importance of hybrid imaging in making decisions about myocardial revascularization.

Aim. To study the parameters of myocardial blood flow (MBF) and coronary flow reserve (CFR) in patients with heart failure (HF) with preserved ejection fraction and evaluate their relationship with the severity of HF.Material and methods. The study included 47 patients (men, 68,7%) aged 65,0 (58,0; 72,0) years with left ventricular ejection fraction of 62 (56; 67)% and coronary artery stenosis Results. Depending on NT-proBNP levels, the patients were divided into 2 groups (pConclusion. A decrease in CFR in patients with HF with preserved ejection fraction indicates impaired myocardial blood supply, which, in this group of patients, is associated with microcirculatory changes. At the same time, the severity of MBF alterations is closely related to HF severity.

Congenital pulmonary venolobar syndrome (CPVS) is one of the most rare and difficult to diagnose combination of vascular abnormalities, combining venous, arterial, pulmonary and cardiac pathology. About a quarter of patients with CPVS have concomitant congenital heart defects (coarctation of aorta, tetralogy of Fallot, patent ductus arteriosus or ventricular septal defect). Other congenital abnormalities include bronchogenic cysts, horseshoe lung, additional diaphragm, and hernias. There are descriptions of isolated cases of this disease in the literature. The article represents an extremely rare case of CPVS associated with intra-thoracic heterotopic liver tissue in an 8-month-old boy.