With the participation: All-Russian Scientific Society of Specialists in Clinical Electrophysiology, Arrhythmology and Pacing, Russian Association of Cardiovascular Surgeons Endorsed by: Research and Practical Council of the Ministry of Health of the Russian Federation

Russian Society of Cardiology (RSC). With the participation of Russian Scientific Society of Clinical Electrophysiology, Arrhythmology and Cardiac Pacing, Russian Association of Pediatric Cardiologists, Society for Holter Monitoring and Noninvasive Electrocardiology. Approved by the Scientific and Practical Council of the Russian Ministry of Health.

Despite the recent achievements in searching for the causes of monogenic human diseases, there is still a massive gap in understanding the molecular causes of phenotypic variability. At the moment, it is evident that the pathogenic genetic variant often acts together with the other genetic and non-genetic factors that can reduce or, on the contrary, aggravate the severity of the disease. Thus, to completely understand the disease, we shall consider the entire set of mechanisms leading to the resulting phenotype. This paper reviews the current state of the art in identifying genetic and non-genetic phenotype modifiers for rare monogenic cardiovascular diseases.

Rhythm and conduction disorders of the heart occupy one of the leading places in the structure of cardiovascular pathology in children. Supraventricular tachycardias means tachyarrhythmias, caused by abnormal myocardial excitation with the source of rhythm localization above the His bundle bifurcation — in the atria, atrioventricular junction (node), and also arrhythmias with circulation of the excitation wave between the atria and the ventricles with additional atrial compounds. The team of authors presents clinical recommendations developed on the principles of evidence-based medicine, including all stages of diagnosis and treatment of children with supraventricular tachycardias. The use of recommendations in clinical practice allows to selecte the best strategy for diagnosis and treatment of supraventricular tachycardia in a particular patient.

In order to study the peculiarities of children’s adaptation to the impact of moderate chronic stress we examined 177 healthy children from 10 to 12 years, who began to study in various institutions. We studied the volume of the educational load, academic performance, parameters of vegetative homeostasis, personal characteristics and the style of adaptive behavior. The cardiovascular system was evaluated by daily ECG monitoring and blood pressure. The duration of follow-up was 2.5 years. Adaptation of children, regardless of the type of educational institution, was accompanied by a tension of the vegetative regulation mechanisms. The children with formed adaptive personal resources and a balanced state of the autonomic nervous system adapted most successfully. At the beginning of adaptation we observed increase in blood pressure in 25.4% of children, and arterial hypertension in 3.3% of children. In 24 months there was found sinus bradycardia in 8.5% of children. Regardless of the type of institution, the depletion of adaptive capacity was associated with abnormalities in the state of the children’s health, low training effectiveness and poor tolerance of educational load. Thus, we believe that personal characteristics, styles of adaptive behavior and the state of vegetative regulation mechanisms should be taken into account when preparing recommendations for the training and organization of medical and psychological-pedagogical support for students.

To assess the information value of tilt-test in pediatric patients with the sinus node dysfunction and syncope, 88 children and adolescents aged 14±2.8 years (4 18 years) were examined, including 52patients with the sick sinus syndrome and 36 children free of cardiac arrhythmias.

This article deals with the 23-years assessment of natural history of 57 patients with paroxysmal supraventricular tachycardia debuted in childhood. Variants of clinical course of disease are described: cardiac, syncopal, abdominal, asymptomatic. in absence of treatment majority of paroxysmal tachycardias were characterized by wavy change of their clinical manifestations with periods of pronouncedly increased and decreased activity lasting from 3 to 5 years. Time interval between attacks was important for prognosis. Severity of disease was determined by relationship of three factors: frequency, duration of attacks and ability of a tachycardia to cause disturbances of central hemodynamics. Tachycardia with asynchronous AB conduction and heart rate above 250/min in one year old and above 220/min in older children was associated with increased risk of development of acute heart failure during an attack. Risk of heart failure was not related directly to frequency of attacks but arose when duration of tachycardia with critical heart rate exceeded 8 hours.

In the present study we have analyzed X chromosome inactivation patterns in 40 women aged from 74 to 85 years (mean age 78 years). The control group was 36 women (mean age 30 years). The most common AR-assay was used to determine X-inactivation patterns (the study of methylation patterns of HpaII site in human androgen receptor gene (HUMARA) by quantative PCR). The age dependence of X-inactivation was not observed. We have detected skewed X-inactivation in three women among 40 (7.5%) elderly women comparing to two women among 36 (5.5%) women from control group. The difference was not found to be statistically significant. We made a suggestion that higher incidence of skewed X-inactivation in elderly women revealed by previous studies could occur due to some experimental ambiguities as heterogeneity of the group studied; inclusion of women having relatives with genetic abnormalities associated with skewed X-inactivation patterns; the difference of X chromosome inactivation skewing determination. We conclude that present study does not show X chromosome inactivation to be age dependent.

Titers of autoantibodies to nerve growth factor, water-soluble astrocytic protein S-100, glial fibrillary acidic protein, and MP-65 membrane protein of the nervous cell superfamily of integrins was determined by solid-phase immunoenzyme assay in healthy children and in children with the Romano-Ward and sick sinus syndromes. Immunoreactivity to these antigens was either increased or decreased in 20% of sick children in comparison with that of healthy children of the same age.