[Effect of the sympathetic nervous system activation on the antifibrillatory efficacy of various anti-arrhythmia agents].

Experiments with a 7-min occlusion followed by reperfusion of the left coronary artery in narcotized rats showed that antiarrhythmic drugs of various classes--ethacizin (class I), AL-275 (class III), and CM-345 (class V)--produce pronounced antifibrillatory and antiarrhythmic effects. AL-275 and CM-345, in contrast to ethacizin, retained their efficacy under the conditions of isoproterenol-induced stimulation of beta-adrenoceptors. This difference in behavior is probably explained by dissimilar effects of the antiarrhythmics on the ion channels of cardiomyocite membranes.