Abstract: Asatum heterotropoides (A. H) was shown to improve the left ventricular pump function and myocardial contractility in dogs.After an intravenous injection of A.H at a dose of 0.1～0.4ml(1:2)/kg in the dog heart-lung preparation (HLP), the results were as follows: LVSP↑, LVEDP↓, MAP↑, CO↑, HR↑, SV↓, dp/dt max↑, -dp/dt max↑, t-dp/dt max↓, Vpm↑, Vce-cpip↑, Vmax↑, After an intravenous injection of A.H at a dose of 0.05～0.4 ml (1:2)/kg in anesthetized open-chest dogs, with exception of MAP↑, and SV↑, similar resulte were obtained (LVSP↑, LVEDP↓, CO↑, HR↑, dp/dt max↑,-dp/dt max↑, t-dp/dt max↑, Vpm↑, Vce-cpip↑, Vmax↑). In the two experiments, positive down curve of Lissajous figure were removed to the right up position.Since the HLP is devoid of inferences of the pre-and after-load of the heart, the increase of pump function by A. H seems to be the result of direct action on myocardial contractility.The result of A. H on cardiac functions and hemodynamics in comparison with Higenamine (H. G) and Isoprenaline (I. S) showed that all drugs increased the left ventricle function. The only difference was that A. H increased SV and H. G、I. S decreased SV. The difference could attribute to the effect of A. H to heart rate that make the increase of heart rate in more proper level than the other two agents.After β-Adrenergic blockade, the effect of A. H on the elevation of CO was unchanged.