心肌梗塞是冠状动脉闭塞,血流中断,使部分心肌严重持久性缺血而发生局部坏死。其临床表现为:发病前心绞痛症状加重、频繁发作和持续时间长等先兆症状,尤其在休息时发作心绞痛更应注意,但也有发病前无先兆症状者。主要表现是突然发作的胸骨后压榨性剧痛,可放射到左肩、左上肢或下颌部,同时常伴有出汗、恶心、呕吐和烦躁不安。与心绞痛不同的是症状严重难于忍受且持续时间长,含服硝酸甘油片也不能缓解。老年 Myocardial infarction is a coronary artery occlusion, blood flow interruption, so that part of the myocardial serious persistent ischemia and local necrosis. The clinical manifestations are: pre-onset angina aggravated symptoms, frequent attacks and long duration of aura symptoms, especially during rest episodes of angina pectoris should pay more attention, but there are no prior symptoms before onset symptoms. The main manifestation is a sudden onset of severe post-sternal pain that can radiate to the left shoulder, left upper extremity or lower jaw, often accompanied by sweating, nausea, vomiting and restlessness. Unlike angina pectoris, the symptoms are severe and difficult to tolerate and persist for a long time. Nitroglycerin tablets can not be relieved either. elderly