Congestive heart failure model in rabbits: effects of digoxin and a drug containing toad venom.

A low-output-type heart failure model was established in rabbits by protease treatment of the surface of the left ventricular anterior wall. Heart rate, aortic blood flow (AoF), left ventricular pressure (LVP) and maximal rate of rise of LVP (max dP/dt) in this model were maintained at lower levels than in normal rabbits, while left ventricular end-diastolic pressure (LVEDP) and systemic vascular resistance (SVR) were maintained at higher levels, and mean blood pressure (MBP) remained at a normal level. Intraduodenal administration of digoxin and a drug containing toad venom (Kyushin:KY) improved the hemodynamic parameters by increasing the AoF, LVP and max dP/dt and by decreasing the LVEDP and SVR without a significant change in MBP. These results suggest that the beneficial effects of digoxin and KY on this heart failure model originate from their cardiotonic activity.