OBJECTIVETo observe the effect of Zhimu and Huangqi on increasing heart rate and cardiac hypertrophy, and its bradycardia effect, to evaluate the exercise capacity and response to stimulation and to discuss the use of Zhimu in treating heart failure.

METHOD1. Rats were treated with isoproterenol 1.25 micrograms.kg-1 i.p., and then the increasing of heart rate and the bradycardia effect were measured after administrated with Zhimu or Huangqi for 3 days. 2. Mice cardiac hypertrophy model was established by s.c. ISO 1 mg.kg-1, 2 times per day for 14 days and heart-weight-index was measured after Zhimu and Huangqi was given orally alone or jointly for 14 days. 3. Abdominal aorta banding operation was done in mice and 3 weeks after operation, they were administrated for 2 weeks, and then run-time(exercise capacity), quiet heart rate, ISO response heart rate after i.p. isoproterenol and heart-weight-index were measured. 4. Cardiac hypertrophy model (inject ISO 14 days) mice were administrated for 12 days, and the mortality and dying time of mice in cold (-20 degrees C) and heat(45 degrees C) stimulative condition were observed.

RESULTZhimu could cut down the increasing of heart rate induced by ISO, decrease significantly heart-weight-index in cardiac hypertrophy mice, reduce the quiet heart rate and prolong the run time in abdominal banding model. Zhimu combined with Huangqi could also improve the ISO response in abdominal banding model mice, reduce the mortality and delay dying time of mice in stimulative condition.

CONCLUSIONZhimu combined with Huangqi can slow down heart rate, enhance the reserve force of the heart, and improve the response capacity of cardiac hypertrophy mice in stimulative condition.