研究表明，心肌梗塞（ＭＩ）后应用β阻滞剂可防止缺血并发症及心性猝死从而降低总死亡率。缺血性心脏病患者５０％死于心性猝死，美国每年约有３０～４０万人死于心性猝死。急性缺血后所致的心室纤维性颤动（ＶＦ）是猝死的主要原因。部分患者ＶＦ发生前无任何先兆症状。为降 Studies have shown that the use of beta blockers after myocardial infarction (MI) prevents ischemic complications and sudden cardiac death, thereby reducing overall mortality. Fifty percent of patients with ischemic heart disease die of sudden cardiac death, and about 300,000 to 400,000 people die of sudden cardiac death each year in the United States. Ventricular fibrillation (VF) due to acute ischemia is the major cause of sudden death. Some patients with VF before the onset of any aura symptoms. To drop