RESUMO
Object To study the effective portion in Cornus officinalis Sieb. et Zucc. extract (COE) for the treatment of arrhythmia. Methods Effect of COE on chloroform induced ventricular fibrillation in mice and electrophysiology of isolated guinea pig papillary muscle were studied. Results Antiarrhythmic effect of COE may be related to its prolongation of action potential duration, increase of the absolute value of resting potential and a decrease of autonomy of sinus node. The effective portion in COE may be its total organic acid and a certain yet unknown trace substance, whereas its total glycosides were devoid of such activities. Conclusion Pharmacodynamic and myocardial electrophysiologic studies showed that the total organic acid and a certain unknown trace substance possessed the obvious antiarrhythmic activity.