[Effect of tests with dosed physical load on sinus node function and repolarization in children with hereditary long QT syndrome].

The study is devoted to assessment of effect of physical effort of sinus rhythm rate and the state of the process of repolarization in children with 1 and 2 molecular-genetic variants of the long QT syndrome (LQT). We have shown that LQT1 is characterized by inadequate increment of heart rate (HR) and substantial increase of QTc interval during exercise. In LQT2 compared with control reduction of HR increment also takes place while shortening of QTc interval is more pronounced. Delta QTc<0 is an important differential diagnostic criterion in patients with LQT1 and LQT2. Variatins in T wave morphology in LQT1 and LQT2 diminish at the background of physical exercise. The use of ß-blockers influences relationship between length of QT interval and HR in patients with LQT but does not eliminate distinction from a group of patients with analogous variant of the syndrome not taking these drugs.

[Diagnosis, sudden death risk stratification, and treatment of main long QT syndrome molecular-genetic variants].

Inherited long QT syndrome (LQTS) refers to the primary electrical diseases of the heart. It is characterized by QT prolongation on resting ECG and syncope due to life-threatening ventricular arrhythmias. This review focuses on diagnosis, differential diagnosis, risk stratification of sudden cardiac death, and treatment strategy of patients with most prevalent genetic fOrms of LQTS - LQT1, LQT2 and LQT3, which accounted for about 90% of all genetically confirmed cases. Recent advances in understanding of relationship between clinical, electrocardiographic features (on ECG, body surface mapping, stress test) and genetic variants of LQT presented. Characteristics of syncopal events and ECG features of LQTl, LQT2 and LQT3 in the majority of cases are helpful to make an appropriate choice for therapy, even before positive result of molecular genetic testing. Management has focused on the use of beta blockers as first-line treatment and exclusion of triggers of life-threatening arrhythmia which are specific for each molecular-genetic variant. Implantation of cardioverter defibrillator for secondary prevention of sudden death in the high-risk patients or patients with insufficient effect of antiarrhythmic therapy is required.

[Relationship between activity of fibrinolysis, parameters of lipid spectrum and carbohydrate metabolism].

In this work analysis of results of a prospective populational cohort study "Stress and health in Russia" is presented. We included in the study inhabitants of Moscow randomly sampled from the population of men and women aged > or =55 years. Aim of the present work consisted in the study of relationship of activity of fibrinolysis and main parameters of the system of lipoproteines providing transport of lipids in blood serum and system controlling utilization of glucose by tissues. In dependence on fibrinolytic activity all examined persons were divided into 3 groups: with hypofibrinolysis (group 1, n=41.5%), with normofybrinolysis (group 2, n=41.9%), and hyperfibrinolysis (group 3, n=16.6%). In persons of group 1 low fibrinolytic activity and high level of fibrinogen were combined with atherogenic spectrum of blood serum lipids and elevated level of insulin at normal level of glucose. In patients of group 3 elevated fibrinolytic activity was combined with more favorable composition of blood lipids, lower levels of insulin and glucose and absence of obesity. At study of relation between fibrinoltic activity and a row of clinical states by the method of logistic regression a tendency to elevation of prevalence of myocardial infarction in persons with hypofibrinolysis was found while in persons with hyperfibrinolysis a significant lowering of prevalence of arterial hypertension, ischemic heart disease, and angina pectoris was observed.

[Determination of the cause of repetitive syncopal States with the help of registration of electrocardiogram at the background of provocative test].

A clinical case of repetitive syncopal states in an adolescent with episodes of significant asystoles lasting up to 32 s is presented. These episodes were detected only with the help of electrocardiogram registered during provocative test. Beyond provoking factors the child had signs of insignificant sinus node dysfunction which did not allow to designate the state of the patient as severe and prescribe adequate treatment. We consider this case as demonstration of necessity of provocative tests in conjunction with ECG monitoring in children with episodes of fainting (syncopal states).

[Normal values of temporal parameters of ECG in children according to results of clinico-epidemiological study ECG-screening of children and adolescents in Russian federation].

In order to obtain reliable information about time-domain ECG parameters in Russian children and to analyse their links with physiological changes the Project "ECG screening of children and adolescents of the Russian Federation" was carried out in 2003-2008. Time domain ECG parameters were studied in the representative sample of 5387 healthy individuals aged 0 to 18 years. In each age group, lower and upper limits of the norm for heart rate (HR), P wave, PQ and QRS intervals were defined as 2nd and 98th percentiles of their distribution. The equivalent limits of QT interval duration were defined as its 5th and 95th percentiles. Relationship between time domain parameters of pediatric ECG and HR was analyzed as well as relationship of these parameters with sex and age. The most important differences from prior pediatric studies completed 30 years ago were obtained for the heart rate limits. Among children aged 0 to 3, there was a tendency toward lowering of age-specific lower limits and elevation of age-specific upper limits. At ages older than 3 years, there was a tendency toward lowering of both the upper and the lower limits of HR. The newly obtained 2nd percentiles of the heart rate were lower than the known lower limits in nearly all ages. This indicates the necessity for revision of criteria of bradicardia in children. The present study showed that 5th and 95th percentiles of QTc interval (Bazett's formula) varied between 340 ms and 465 ms and were not significantly dependent on children's age and only for ages under 13 also on sex. Results of the study allowed to build age-specific ranges of norm for the time domain ECG parameters presented in a tabular form.

[Metabolic peculiarities of dyslipoproteinemias unrelated to high level of blood cholesterol].

The aim of this study was to reveal whether atherogenic or nonatherogenic properties of dyslipoproteinemias (DLP) not related to high level of blood total cholesterol (C) and low density lipoprotein C (LDL C) are determined only by shifts in serum triglycerides (TG) and/or high density lipoprotein cholesterol (HDL C) levels, or by other lipoprotein system alterations, if any. Biochemical factors regulating both lipid and carbohydrate metabolism were analyzed in two subsamples of Moscow residents aged 55 years with DLP: "high TG and low HDL C" and "normal TG and high HDL C" in comparison with randomly selected subsample assumed as "normal". Specific biochemical indexes of atherogenicity of DLP "high TG and low HDL C" were found, namely: increased apo B/AI ratio; disturbed functional activity of HDL in promoting reverse cholesterol transport expressed as elevated apo AII/AI ratio, decreased apo AI and phospholipids (PL) levels, decreased ratios of C/apo AI and C/PL in HDL, and decreased cholesterol-accepting capacity of HDL. Moreover, while fasting glucose level in subjects from this group remained unchanged, their fasting insulin level and HOMA-IR index were increased. Thus, DLP "high TG and low HDL C" is characterized by some specific metabolic features underlying its involvement into pathogenesis of atherosclerosis and type 2 diabetes mellitus. On the other hand, differences in biochemical parameters of antiatherogenic DLP "normal TG and high HDL C" from random subsample appeared to be opposite to differences from random subsample found for DLP "high TG and low HDL C", being in line with the present concept about their role in determining the antiatherogenicity of this kind of DLP.

[Remote catamnesis of paroxysmal supraventricular arrhythmias which debuted in childhood].

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.

[Prevalence of electrocardiographical signs of right ventricular arrhythmogenic dysplasia]. / Rasprostranennost' élektrokardiograficheskikh priznakov aritmogennoi displazii pravogo zheludochka u bol'nykh s idiopaticheskimi zheludochkovymi takhiaritmiiami.

UNLABELLED: Right ventricular arrhythmogenic dysplasia (RVAD) is a state with high risk of sudden death in young patients. Early diagnosis of RVAD can facilitate sudden death prevention. AIM: To assess prevalence of electrocardiographical signs of RVAD among children with "idiopathic" tachyarrhythmias. MATERIAL: Patients without organic heart disease or overt noncardiac causes of arrhythmia aged 4-17 years (n=134, mean age 12+/-4.5 years, 56 girls and 76 boys) including 82 patients with >5000 extrasystoles VE 24 hours and 52 patients with ventricular tachycardia (VT). All patients had QTc interval <440 ms. METHODS: Twelve lead ECGs from all patients were analyzed for determination of morphology of arrhythmia and presence of "major" (epsilon wave and QRS duration >110 ms in V(1)-V(3)) and "minor" (VT with left bundle brunch block - LBBB, VE >1000/24 hours, T-wave inversion in V(2) and V(3)) diagnostic criteria for RVAD (W.McKenna, 1994; D.Corrado, 2000). RESULTS: ECG signs of RVAD were found in 28 of 58 (48.3%) of patients with VE and in 1 of 24 patients (4.2%) with atrial extrasystoles. Among patients with VE 27 (96.4%) had extrasystoles with LBBB morphology and 1 (3.6%) - with right bundle brunch block (RBBB) morphology. Combination of major and minor criteria sufficient for diagnosis of RVAD was found in 19% (8 of 42) of patients with VE with LBBB. Among 52 patients with VT 21 had polymorphic VT and 31 - monomorphic VT (16 with LBBB and 15 with RBBB). Epsilon wave was present in 56.3% (9/15) of patients with monomorphic VT and LBBB, in 4.8% (1/21) of patients with polymorphic VT and in none of the patients with monomorphic VT and RBBB. QRS duration exceeded 110 ms in 2 (12.5%), 2 (9.5%) and 0 patients among those with monomorphic VT and LBBB, polymorphic VT, and monomorphic VT and RBBB, respectively. Among patients with monomorphic VT and LBBB 37.5% (6/16) had combination of ECG criteria sufficient for diagnosis of RVAD. In 3 patients epsilon wave was registered in lead V(1) immediately prior to VT and disappeared after VT cessation. Implications. It can be suggested that presence of polymorphic VT or VE with LBBB morphology and specific ECG changes (first of all epsilon wave and QRS widening) distinguishes a group of patients with high risk of RVAD which requires thorough cardiological examination and dynamic observation.

[Serotonin transporter gene polymorphism and factors influencing mental and physical health in aging]. / Sviaz' polimorfnykh variantov gena perenoschika serotonina s faktorami, vliiaiushchimi na fizicheskoe i psikhicheskoe zdorov'e v protsesse stareniia.

Genetic predisposition is thought to exert a certain influence on the indices related to longevity and quality of life. Many of the indices, namely cognitive functioning, stress resistance, metabolism control, may be related to serotonin activity. To study polymorphic serotonin transporter gene variants and their association with features relevant for survival and longevity prognosis, a sample of elderly Russians from Moscow community recruited in the project "Stress-related mechanisms in Russia", comprising 196 subjects, mean age 76.2+/-5.3 years, 155 men, 41 women, has been genotyped. Allele and genotype frequencies have been estimated in 3 groups, aged 60-69, 70-79 and 80-87 years, respectively. A trend (chi2=4.1; p=0.12) to the prevalence of individuals with SS genotype (21.8%), as compared to expected level (14.6%), was found in the group of octogenarians (n=55, mean age 82.8+/-1.9 years). An association analysis between genotype and physiological traits revealed a genotype contribution to past smoking on tendency level (p=0.069), waist to hip ratio (WHR) (p=0.012) and plasma insulin concentration (p=0.02), with a higher frequency of SS genotype among non-smokers and subjects with lower WHR and insulin concentration. Genotype effect on the traits was stronger, being considered in interaction with the age above 80 years. Genotype was not associated with cognitive functioning (MMSE), but proved to be a significant predictor of MMSE performance (p=0.03) in octogenarians. The results obtained are in line with current concepts of serotonin role in smoking, obesity and cognitive functioning.

[X chromosome inactivation pattern in elderly women over 70 years of age]. / Osobennosti inaktivatsii khromosomy X u pozhilykh zhenshchin starshe 70 let.

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.

[Current trends of cardiovascular morbidity and mortality of children in Russian Federation. Structure of cardiac pathology in childhood]. / Sovremennye tendentsii serdechno-sosudistoi zabolevaemosti i smertnosti u detei v Rossiiskoi Federatsii; struktura serdechnoi patologii detskogo vozrasta.

Analysis of structure and prevalences of cardiovascular diseases among children and adolescents is presented and recent trends of cardiovascular morbidity and mortality as well as regional differences in dynamics of these parameters in this age group are discussed. Current situation is characterized by pronounced lowering of age of onset of cardiovascular diseases previously considered as diseases of the adult. Clinical picture and prognosis of many pathological states also has been changed. Since the beginning of the nineties steep rise (more than 2 fold) of morbidity and total number of children with cardiovascular pathology has occurred. This is directly linked with improved diagnostics. While all cause and infant mortality becomes lower cardiovascular mortality remains stable and even has tendency to increase. Mortality from cardiac and vascular diseases is significantly lower in regions with higher prevalence of these states. Substantial effect on lowering of mortality produces intensity of work of specialized services providing timely diagnosis, treatment and rehabilitation of children with heart diseases. The authors suggest some parameters allowing to assess progressive or negative trends in development of specialized care of children with cardiovascular pathology.

[Circadian structure of cardiac rhythm in tachyarrhythmia]. / Sutochnaia struktura ritma serdtsa pri takhiaritmiiakh.

AIM: To determine clinical implication of changes in the structure of circadian cardiac rhythm in patients with tachyarrhythmia basing on estimation of the circadian index (CI). MATERIAL AND METHODS: 24-h Holter monitoring was conducted in 154 patients aged 4 to 18 years: 125--with supraventricular paroxysmal tachycardia, 13--with long Q-T interval, 16--with idiopathic ventricular tachycardia. CI was calculated as mean day heart rate (from 7.00 to 22.00)/mean night heart rate (from 23.00 to 6.00). RESULTS: Patients with long Q-T interval had less CI while those with supraventricular paroxysmal and idiopathic ventricular tachycardia had higher CI vs normal values. CI changes became more pronounced with growing disease severity. CONCLUSION: Cardiac arrhythmia with low CI is associated with progressive vegetative denervation while that with high CI occurs in increased cardiac sensitivity to sympathetic impacts.

[Cardiac rhythm in sleeping healthy adolescents as recorded by holter ECG monitoring]. / Struktura ritma serdtsa v period sna u zdorovykh podrostkov po dannym kholterovskogo monitorirovaniia EKG.

AIM: To characterise cardiac rhythm dynamics in sleeping adolescents by heart rate trend in Holter monitoring (HM). MATERIALS AND METHODS: Synchroneous HM and classical night EEG-polygraphy from 22.00 to 08.00 were conducted in 9 healthy adolescents (5 boys and 4 girls) aged 10-15 years. The heart rate trends in sleep exhibited periods of stable rhythm (PSR) and periods of enhanced dispertion (PED) which took 38.4 and 61.6% of the sleep duration, respectively. PED occurred 5.3 +/- 0.16 times per night. The comparison of the heart rate trends to night sleep structure reflected at EEG indicated that fast sleep coincided with PED in 100% of cases being in the middle of PED cycle. PED incorporated also fragments I and II of slow wave sleep (SWS). PSR were represented primarily with phases II and IV of SWS. Step-by-step scanning of the right space of the interval histograms showed that maximal slowering of cardiac rhythm occurred in SWS phase II and fast sleep (76.5 and 23.5%, respectively). CONCLUSION: The profile of the heart rate night trend in HM reflects an independent ultradian rhythm. Maximal cardiac rhythm unstability and bradycardia occurred, respectively, in fast sleep and phase II of SWS.

[Histographic analysis of the heart contraction rate during Holter monitoring of patients with arrhythmias]. / Gistograficheskii analiz chastoty serdechnykh sokrashchenii pri kholterovskom monitorirovanii EKG u bol'nykh s serdechnymi aritmiiami.

Heart rate histograms were analyzed during 24-hour Holter monitoring in patients with cardiac rhythm and conduction disturbances. The profiles of histograms in the most common cardiac arrhythmias: extrasystole, chronic supraventricular reentry tachycardia, atrioventricular block, sinus tachycardia, sick sinus syndrome and those in patients with implantable pacemakers were shown. Approaches to analyzing histograms were defined in Holter monitoring, the histographic analysis was demonstrated to be of value in the comprehensive evaluation of Holter monitoring findings.

[Clinico-physiological characteristics of syncopal conditions in the long QT syndrome (Romano-Ward syndrome)]. / Kliniko-fiziologicheskaia kharakteristika sinkopal'nykh sostoianii pri sindrome udlinennogo intervala Q-T (sindrom Romano-Uorda).

A complex of methods including clinical analysis, ECG, and exercise EEG was used to examine 52 patients aged 2 to 20 years with Romano-Ward syndrome. There were two groups: group I with syncopal attacks, group II without them. The patients with Romano-Ward syndrome had dysfunction of the suprasegmental systems regulated autonomously in the form of functional insufficiency of the mesencephalic activating system. In the patients without syncopal attacks, there was hyperproduction of the theta-rhythm, which may reflect the mechanisms of compensation. According to the EEG readings, criteria for the syndrome gravity and sudden death risk factors were distinguished.

[Chronic nonparoxysmal supraventricular tachycardia in children and adolescents]. / Khronicheskaia neparoksizmal'naia supraventrikuliarnaia takhikardiia u detei i podrostkov.

An examination was performed in 111 children and adolescents with recurrent and sustained chronic nonparoxysmal tachycardias (CNPT). ECG and electrophysiological studies showed that ante- and retrograde conduction along the accessory atrioventricular junction was the most common mechanisms of arrhythmia. Holter monitoring revealed a high rigidity of cardiac rhythm in patients with sustained CNPT. Criteria for the development of arrhythmogenic cardiac dilatation were developed. In recurrent CNPT, there was a correlation between the paroxysms of ECG slow-wave activity and the "salvos" of tachycardia and a predominance of vagal effects on the heart. A new approach to the treatment of children with CNPT was proposed, which involved the correction of pathogenetic mechanisms. Indications for the usage of antiarrhythmic agents such as cordarone and a cardiac surgeon's advice were formulated. The efficiency of the therapy was achieved in 82% of the children as shown by a follow-up.