Experimental study on sudden death due to acute myocardial infarction.

为探讨猝死与心肌梗死发生时间的关系，寻找适合检测急性心肌梗死的染色方法，采用结扎左冠状动脉前降支的方法，建立了杂种犬急性心肌缺血的实验模型。在心动周期脆弱期对心脏进行电模拟，估计心室颤动阈值。冠状动脉结扎后15 ~ 30mm心室颤动阈值下降到对照组的20%左右。随着结扎后时间的延长，ii值逐渐升高，结扎后4 h与对照组基本相同。缺血心脏用10%福尔马林溶液固定。缺血心肌切片用Luxol快速蓝（LFB）溶液染色24小时，并在75%酒精的几次变化中分化为微弱的鸽蓝色（一种新改良的LFB染色）1-3分钟。新改良的LFB染色显示冠脉结扎后15-30 min心肌缺血变化。结果提示，心肌梗死发病后15 ~ 30 min最易发生室性颤动性猝死，新改良的LFB染色法可用于早期心肌梗死的检测。

To Investigate the relatlonshIp between sudden death and the time elapsed after the onset of myocardial infarction and to find a suitable staining method for detection of acute myocardial Infarction, an experimental model of acute myocardial ischemia was made with mongrel dogs by ligating anterior descending branch of left coronary artery. The heart was given electrical simulation at the vulnerable period of the cardiac cycle and the ventricular fibrillation threshold was estimated. Ventricular fibrillation threshold decreased to about 20 % of those of the control hearts 15-30 mm after the coronary artery ligation. Then ii increased with the time elapsed after the coronary ligation and showed almost same values as those of control hearts 4 h after the coronary ligation. The ischemic hearts were fixed with 10 % formalin solution. The sections from the ischemic heart muscle were stained with Luxol Fast Blue (LFB) solution for 24 h and were differentiated for 1-3 min in several changes of 75 % alcohol to a faint dove-colored blue (a newly modified LFB staining). The newly modified LFB staining revealed the myocardial ischemic changes 15-30 min after the coronary ligation. The result suggested that sudden death from ventricular fibrillation is the aptest to occur 15-30 min after the onset of myocardial infarction and the newly modified LFB staining Is useful for detecting such very early myocardial infarction.