Improvement of cardiac function after cardiopulmonary resuscitation by using isosorbide mononitrate in porcine models

Abstract

Objective To determine the protective effect of isosorbidemononitrate (IM) on myocardial injury after restoration of spontaneous circulation (ROSC) in swine models of cardiac arrest induced by ventricular fibrillation. Methods The experiment was carried out in Animal Lab of Beijing Chao-Yang Hospital, Capital Medical University. Ventricular fibrillation was induced and untreated for 8 min in twenty WhuZhiShan piglets. CPR was performed until ROSC occurred. The animals were randomized(random number) into two groups: IM group (n=10) and control group (n=10). IM [2 μg/(kg·min)] or the equivalent volume in saline was administered respectively for 6 h after ROSC. Hemodynamics and post-resuscitation cardiac function were monitored until 24 h after ROSC. Echocardiography and transmission electron microscopy were useed at 72 h after ROSC. Results There was no significant difference in survival rate between the two groups. No significant differences in mean arterial pressures(mmHg)at ROSC 6 h (88.5±5.6 vs. 87.8±6.0, P=0.790) and ROSC 24 h (89.3±3.8 vs. 86.9±5.0, P=0.245) between the two groups were found. Cardiac outputs(L/min) were significantly increased at ROSC 6 h (2.40±0.17 vs. 1.60±0.14, P<0.01) and ROSC 24 h (2.49±0.17 vs. 2.09±0.21, P<0.01); and ejection fraction at ROSC 72 h (0.67±0.08 vs.0.56±0.09, P=0.044) was improved too, and significant differences were found between the two groups. The ultra-structural myocardial injury was ameliorated in the MI group at 72 h after CPR observed by using electron microscopy. Conclusions IM can ameliorate post-resuscitation cardiac dysfunction in porcine models of cardiac arrest induced by ventricular fibrillation. Key words: Cardiac arrest; Isosorbide mononitrate; Ventricular fibrillation; Pig; Cardiopulmonary resuscitation; Myocardial stunning