EFFECT OF ASARUM HETEROTROPOIDES ON THE LEFT VENTRICULAR FUNCTION OF DOGS

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.