Abstract: The enhanced cardiac contractility effect of human recombinant growth hormone (hr-GH) on the congestive heart failure (CHF) was studied on the pig. To build a pig model of congestive heart failure, a temporary artificial cardiac pacemaker was implanted in the pig's body and paced at 220 beats to 240 beats per minute for 1 week. After the model of congestive heart failure was successfully set up, the frequency of the pacemaker was changed to 150 beats to 180 beats per minute to maintain the CHF model stable. Pigs were divided into three groups: The hr-GH group in which 0.5 mg/kg per day of hr-GH was administrated intramuscularly for 15 days, the injection control group in which an equal amount of physiological saline was injected intramuscularly, and a normal control group. The left ventricular diastolic end pressure was (10.60±2.41) mmHg in the hr-GH group, but (19.00±3.81) mmHg in the saline control group (P<0.01); Cardiac output was (1.86±0.13) L/min in the hr-GH group, but (1.56±0.18) L/min in the saline control group (P<0.05); Peripheral vascular resistance was (56.88±7.51) mmHg·(L/min)^-1 in the hr-GH group, whereas (70.30±11.59) mmHg·(L/min)^-1 in the saline control group (P<0.05); +dp/dt_max was (2900±316.23) and (2280±286.36) in the hr-HG group and the saline control group respectively (P<0.05). The results show that hr-GH enhances myocardial contractility of CHF, and the CHF model built by a temporary artificial cardiac pacemaker at a high rate of stimulation is reasonable and applicable.

Key words: improved cardiac contractility, human recombinant growth hormone, experimental animal model, temporary artificial cardiac pacemaker, congestive heart failure