猪急性心肌梗死模型发生心室颤动的相关因素分析

Risk Factors of Ventricular Fibrillation in Open-Chest Acute Myocardial Infarction Models of Swine

目的探讨猪冠状动脉前降支(LAD)结扎后发生室颤的特点及其相关因素,以期提高猪急性心肌梗死模型的成活率。方法57只小型猪开胸结扎心脏LAD不同位点,对室颤和体重、性别、术前心率、术前左室射血分数(LVEF)、开胸径路(旁正中/肋间)、手术时间、结扎百分位点、术后心率、术后发生室早或短阵室速等因素进行单因素相关分析和Logistic回归分析,进而对室颤的发生时间、室颤前心电图特点等进行评价。结果57例动物手术过程发生室颤18例,死亡11例。室颤均发生在结扎冠脉后35 min内,高峰时间为结扎冠脉后5 min和20 min;心率快于160 bpm或慢于60 bpm时容易诱发室颤。与非室颤组动物比较,室颤组动物的结扎位点高,术后最快心率>60 bpm的动物较多,短阵室速发生率高(P<0.01)。Logistic回归分析显示结扎位点过高是急性心肌梗死后发生室颤唯一的独立危险因素。结论结扎位点过高是猪急性心肌梗死后发生室颤的最重要危险因素;冠脉结扎后30 min内应该严密心电监护,特别注意结扎冠脉后5 min和20 min二个时间点、>160 bpm或<60 bpm二种心率、以及短阵室速等先兆事件。

Objective To explore the characteristics and risk factors of ventricular fibrillation （Vf） in open-chest acute myocardial infarction models of swine. Methods Coronary artery was surgically occluded at different percentage point of LAD varying from 25 % to 75 % in fifty-seven miniswines. Cardiac fraction （LVEF） using echocardiography was assessed before and 1 hour after myocardial infarction （MI）. Coronary angiography was used to confirm the position of ligation after MI. The weight, gender, heart rate （HR） before and after MI, LVEF, thoracotomy route （intercostal or parastemal ）, operation duration, percentage point of LAD ligation, arhythmia after MI were recorded and compared between Vf group and Vf-free group, The risk factors of Vf were determined by logistic regression analysis. Results Eighteen of the 57 pigs suffered from ventricular fibrillation within 35 rain after LAD ligation and 11 cases died. Compared with Vf-free group, the Vf group featured a higher position of LAD ligation, a higher incidence of ventricular tachycardia and maximal HR 〉 160 bpm post MI. Logistic regression analysis showed the position of LAD ligation was a sole risk factors of Vf after MI with a statistical significance. Pigs with HR 〉 160 bpm or 〈 60 bpm post MI was susceptible to Vf. Conclusion The position of LAD ligation is a vital determinant of Vf in establishing acute MI model of swine. Attentions should be paid to the first 30 min after LAD ligation, HR, and ventricular tachycardia.