A myocardial infarction happens when the blood flow to a part of the heart is blocked for a long enough time that part of the heart muscle is damaged.当流往部分心肌的血液被阻时间过长,心肌因此受损时,就会发生心肌梗塞。Myocardial infarction is the medical term for a heart attack.心肌梗死是心脏病的医学用语。