Functional and metabolic effects of propafenone in the rat heart-lung preparation

The effects of propafenone on cardiac function and myocardial metabolism were assessed in the isolated rat heart-lung preparation. Propafenone 0.3, 3 or 30µg·ml^–1 was administered 5min after the start of perfusion. Heart rate decreased in the 30µg·ml^–1 group significantly following the drug administration. The highest dose of propafenone (30µg·ml^–1) reduced cardiac output significantly, and this dose was associated with a higher incidence of arrhythmias than the other groups. Although there were no significant differences in myocardial lactate and glycogen concentrations among groups, ATP content in the 30µg·ml^–1 group was significantly less than that in the control group. As therapeutic plasma concentration of propafenone is about 0.6 (range 0.06 to 1.0) µg·ml^–1, 30µg·ml^–1 is 50 times greater than its concentration. These results suggest that the negative inotropic and chronotropic effects of propafenone are almost same with those of lidocaine which we have previously reported.(Kashimoto S, Oguchi T, Nakamura T, et al.: Functional and metabolic effects of propafenone in the rat heart-lung preparation. J Anesth 5: 392–395, 1991)