患者,男,80岁。既往有高血压,无冠心病史,最近1个月内连续发生3次胸闷伴呼吸困难,每次持续时间不到5min即自行缓解。今凌晨再次发作,来门诊就诊。在询问病史时,患者突然出现胸闷,遂及时给予舌下含服硝酸甘油0.5mg,约2min后,患者胸闷症状缓解。5min后突然面色苍白,呼之不应,头下垂,身体从椅子上往下滑。测血压 Patient, male, 80 years old. Past history of hypertension, no history of coronary heart disease, chest tightness accompanied by respiratory distress in the last 1 months consecutive 3 times, each duration less than 5min that ease. This morning attack again, to the clinic. When asked for medical history, the patient suddenly had chest tightness, and then promptly given sublingual nitroglycerin 0.5mg, about 2min, patients with chest tightness symptoms ease. 5min suddenly pale, call should not, head drooping, the body slid down from the chair. Blood pressure