[Relationship between polymorphism of non-coding regions of human mitochondrial genome and primary cardiac conduction disorders]. / Sviaz' polimorfizma nekodiruiushchikh oblastei mitokhondrial'nogo genoma cheloveka s pervichnymi narusheniiami serdechnoi provodimosti.

AIM: Analysis of associations between idiopathic disturbances of cardiac conduction (DCC) and polymorphism of mitochondrial genome. MATERIAL AND METHODS: A family examination was performed in 431 probands with various DCC and 1347 relatives of the first, second and third degree of kinship (the study group). All the examinees were divided into four subgroups. These included 158 probands with atrioventricular block (AVB) of various degree and their 518 relatives (subgroup 1); 50 probands with a complete right bundle-branch block (BBB) and their 161 relatives (subgroup 2); 108 probands with a complete left BBB and left anterior branch of the His bundle and their 152 relatives (subgroup 3); 115 probands with sick sinus syndrome (SSS) and their 327 relatives (subgroup 4). The control group consisted of 104 probands without clinical ECG manifestations of cardiac diseases and their 321 relatives. All the examinees have undergone ECG, atropin test, echocardioscopy, electrophysiological examination of the heart and mitochondrial DNA (mDNA). RESULTS: Comparison of the incidence of mDNA D-loop restriction sites in the group of patients with idiopathic DCC and controls has found higher frequency of the Hae III 16517 site in the group of the patients (p = 0.0480). By location of the blocks (atrioventricular and intraventricular), the site occurred more frequently in patients with AVB (86.36%). The variant "+" by the site of Hae III 16517 mDNA was found to associate with disturbances of cardiac conduction, more closely in AVB. CONCLUSION: Variability of mDNA may be an etiological factor of idiopathic DCC pathogenesis.

[Angiotensin-converting enzyme gene polymorphism in patients with primary disturbances of cardiac conduction]. / Polimorfizm gena angiotenzinprevrashchaiushchego fermenta u bol'nykh s narusheniiami serdechnoi provodimosti.

Increased frequencies of angiotensin-converting enzyme (ACE) D-allele and ID-genotype among patients with idiopathic atrioventricular blocks and I allele and II genotype among patients with idiopathic intraventricular blocks allow to consider these genotypes risk factors of corresponding disturbances of cardiac conduction. Decreased frequency of ACE I allele and II genotype among patients with idiopathic atrioventricular blocks is indicative of a possible protective role of II genotype against development of this type of cardiac conduction defect. Low frequency of D allele and genotype D prevents derangements of conduction in His-Purkinje system.

[New data on etiology of heart conduction disturbances]. / Novoe ob étiologii narushenii vnutriserdechnoi provodimosti.

AIM: To make a clinicogenealogical analysis of different types of heart conduction disturbances in families of Krasnoyarsk city. MATERIALS AND METHODS: 104 probands with ECG-verified idiopathic forms of atrioventricular and intraventricular blocks of different severity and 331 their close relatives (kinship degree I and II) were examined using standard clinical investigations, ECG, echocardioscopy, electrophysical investigations in some cases and coronarography. RESULTS: All the observed 104 families were divided into 3 groups according to the type of heart conduction in proband. Group 1 consisted of 24 probands with atrioventricular block and 80 their relatives. The sick relatives had for the most part atrioventricular blocks (31.2%). 26 probands of group 2 had complete right bundle branch blocks. Of their 81 relatives, the sick ones had primarily conduction disturbances in right bundle branch (incomplete block--44.7%, a complete block--5.2%). Group 3 consisted of 54 probands with left bundle branch block and 170 relatives. The left bundle branch block was present in 27.4% of the relatives. CONCLUSION: A definite family aggregation of heart conduction disturbances was found. This proves genetic determination of this pathology.