The characteristics of myocardial injury in rats resuscitated from cardiac arrest / 中华急诊医学杂志

ABSTRACT

Objective To investigate the characteristics of myocardial injury and its underlying mechanism in rats resuscitated from cardiac arrest. Methods Forty-two male Wistar rats were randomly(random number) assigned into the post-resuscitation (PR) 4 h, PR 24 h, PR 48 h, and sham groups. Ventricular fibrillation was induced by transcutaneous electrical epicardium stimulation and untreated for 6 min, followed by cardiopulmonary resuscitation (CPR). Myocardial function, glucose metabolism, myocardial ultrastructure, the status of mitochondrial permeability transition pore (MPTP) and mitochondrial membrane potential (MMP) were evaluated at different time points. Results Myocardial dysfunction was found at 4 h after restoration of spontaneous circulation (ROSC). The ejection fraction and cardiac output were decreased (all P<0.01), the diastole left ventricular posterior wall became thicker (P<0.01), and the end-diastolic volume was reduced (P<0.05). However, cardiac function was recovered almost completely at 48 h after ROSC. The PR 4 h group had a higher SUVmax, a more obvious decreased absorbance, and a lower MMP than the sham group (all P<0.01), but no statistically significant differences were noted between the PR 48 h group and the sham group (P>0.05). At 4 h and 24 h after ROSC, the mitochondria was swollen and the mitochondrial crista was sparse, but the myocardial ultrastructure was complete. Conclusions Post resuscitation myocardial dysfunction occurs after ROSC and the myocardial dysfunction is completely reversible at 48 h after ROSC, which may be related to the reversibility of myocardial injury and the gradual recovery of mitochondrial structure and function.