Ischemic myocardial contracture occurred in early stage of asphyxia-induced cardiac arrest in rats / 中华急诊医学杂志

ABSTRACT

Objective:To investigate the characteristics of ischemic myocardial contracture after asphyxia-induced cardiac arrest (CA).Methods:Asphyxia and ventricular fibrillation (VF) induced cardiac arrest model was established. Thirty-one male Wistar rats were randomly(random number) assigned to the sham, asphyxia and VF groups. Electrocardiogram and blood pressure during CA stage were recorded. Arterial blood was drawn for blood gas analysis at 0 min after CA. The length and width of the heart were measured at 0,2,4,6 and 8 min after CA. The myocardial ATP contents were measured at 0 and 8 min after CA.Results:Compared with the VF group, the time of CA induction was longer in the asphyxia group[ (237±20 ) s vs (3±1) s, P<0.05]. At 0 min after CA, severe hypoxemia, carbon dioxide retention and acidosis had occurred in the asphyxia group, while these indexes in the VF group were basically normal. The length and width of the heart in the asphyxia group decreased gradually after CA, the myocardial contracture reached the limit around 6 min after CA, while the cardiac morphology of the VF group did not change significantly during the observation period of 8 min after CA. Myocardial ATP content in the asphyxia group decreased significantly at 0 min after CA ( P<0.05), while the difference between the VF group and the sham group was not statistically significant ( P>0.05). Conclusions:Myocardial contracture occurrs in the early stage of asphyxia CA, which may be related to ATP consumption in the asphyxia stage.