[Mechanisms of the development of the terminal state in experimental emotional stress].

The development of ventricular fibrillation associated with experimental emotional stress was studied in chronic rabbit experiments. Changes in myocardial-fibre action potentials, thresholds for ventricular fibrillation and its precursors, blood and myocardial catecholamine levels and heart-muscle ultrastructure were examined. Emotional stress was shown to increase, via sympathoadrenal activation, functional and structural heterogeneity of the myocardium, leading, alongside other causes, to arrhythmias and death from ventricular fibrillation. Moderately prevailing parasympathetic effects on the heart during stress exposure contribute to the elevation of fibrillation and fibrillation precursor thresholds and prevent catecholamine rise and myocardial structural damage.