ИСТИНА

The relationship between anxiety and heart rhythm was studied in 90 subjects divided into four groups with different levels of trait-anxiety under rest and arithmetical load (multiplication of two-digit numbers). ECG was telemetrically recorded and fed into IBM PC via 4-channel polygraph. The method of principle components and the Varimax rotation was used for the factor analysis study of heart rhythm spectra. It was found that all spectra revealed three main orthogonal factors having maximum factor load with metabolic, vascular and respiratory frequency bands respectively. Using three factors as a coordinate system four groups of subjects differed in the level of a trait-anxiety specific groups were located in different areas of the three-dimensional autonomic space and their position were changed under mental load. Two groups of subjects with middle level of trait-anxiety are characterised by the coactivation of respiratory and vascular oscillators of heart rhythm under rest and informational load. Very high level of trait-anxiety in the 4th group was associated with reducing the both respiratory and vascular oscillators during rest and mental load conditions. The arithmetical task evoked the depression of the vascular and respiratory system in all groups of subjects. There is reciprocal relationship between level of trait-anxiety and activation of a metabolic oscillator. The specificity of heart rhythm in the four groups of subjects is discussed in the framework of the relationship between the trait-anxiety and a balance of phasic orienting and defensive reflexes.