Experimental Study Of Postresuscitation Myocardial Function From Ventricular Fibrillation By Echocardiography

【Objective】To investigate the functional changes in the myocardium after successful resuscitation from ventricular fibrillation(VF) by echocardiography.【Methods】Thirty one male Taihu-pigs weighing between 7.5 and 31 kg were investigated.For establishing pig model of sudden cardiac arrest,VF was induced with an AC current delivered to the right ventricular endocardium. After either 2 or 6 minutes of untreated VF, electric defibrillation and cardiopulmonary resuscitation(CPR) was attempted. Transthoracic echocardiography was applied to evaluate myocardial function before VF was induced and after successful resuscitation.The purpose of this study was to analyze the correlation between postresuscitation myocardial function and cardiopulmonary resuscitation.【Results】1. When the duration of untreated VF was increased from 2 to 6 minutes, the achievement ratio of cardiopulmonary resuscitation decrease from 89.47%(17/19)to 50%(6/12); 2. There were no differences in left ventricular ejection fraction(LVEF),fractional area change(FAC),left ventricular end-diastolic volume(LVEDV) and left ventricular end-systolic volume(LVESV) between the group of 2 minutes of untreated VF and the group of 2 minutes with CPR; 3. There were differences in LVEF, FAC, LVEDV and LVESV between the group of 6 minutes of untreated VF and other groups(P<0.05); 4. There were differences in heart rate between the group of 6 minutes of untreated VF and other groups(P<0.05); 5. These differences of cardiac outputs of all animals have not statistically significants.【Conclusion】1.When the duration of untreated VF was prolonged, it decreased in the achievement ratio of CPR and 72-hours survival rate and the severity of postresuscitation myocardial dysfunction would be increased; 2.When the duration of untreated VF was less than 6 minutes, postresuscitation myocardial dysfunction is the reversible heart failure with left ventricular dilation; 3.CPR is helpful to decrease the severity of postresuscitation myocardial dysfunction.