[New data on etiology of heart conduction disturbances]

To make a clinicogenealogical analysis of different types of heart conduction disturbances in families of Krasnoyarsk city.

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.

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.

A definite family aggregation of heart conduction disturbances was found. This proves genetic determination of this pathology.