[Intracardiac neurogenic regulation of the rate of excitation conduction in the atrioventricular area of the heart. I. Dependence of the effect on the moment of stimulus application in spontaneous and artificially stabilized rhythms of the heart beat].

The influence of the intracardiac reflectory system on the atrioventricular propagation in the experiments on the isolated frog's heart has been investigated. The ability of the intracardiac reflectory cholinergic activation to accelerate or reduce the atrioventricular propagation was confirmed. Both effects remain on the background of the artificially stabilized heart rhythm. The dromotropic effect direction was shown not to be connected with the electrocardiogram (ECG) phase at which the stimulus has been given; the positive or negative dromotropic effect can appear giving the stimulus at the same phase of the ECG. But there is a strong correlation between the moment of the stimulation and the dromotropic effect intensity. The most high degree of the acceleration and inhibition appears when the stimulus is given near the P component of the ECG.