Investigation of the antiarrhythmic mechanism of the multi-herbal medicine Xing Su Ning

Introduction. Xing Su Ning (XSN) is a multi-herbal Chinese medicine produced by Momentum Pharmaceutical Co. Ltd., which is sold in China since 2005 for treating cardiac ventricular arrhythmia, especially arrhythmias induced by cardiac ischemia and viral myocarditis. Aims. To discover the cellular electrophysiological mechanism of the actions of XSN in treating cardiac arrhythmia. Methods. Whole-cell patch-clamp techniques (1) were used to record action potentials and whole cell current in isolated adult rat ventricular myocytes. The myocytes were continuously perfused with physiological solution without or with XSN. Results. XSN at 2mg/ml significantly prolonged the action potential Duration (APD) as shown in the Figure: control was 45.4ms±4.9 and with XSN 2mg/ml was 52.2ms±4.5 (P