Keywords: silent myocardial ischemia
The so-called silent myocardial ischemia in patients with no clinical symptoms of angina diagnosis of coronary heart disease have been identified, but the objective indicators of myocardial ischemia, such as ECG typical ischemic ST-segment changes, it is a special type of coronary heart disease. However, due to asymptomatic often ignored by people.
Silent myocardial ischemia is increasingly important, mainly due to the large number of studies in recent years found that about 25% to 50% of acute sudden death, lifetime history of angina pectoris; nearly 90% of the autopsy and found that these persons severe coronary atherosclerotic lesions. About 2% to 4% of the U.S. seemingly healthy asymptomatic middle-aged man, the examination revealed significant coronary lesions and silent myocardial ischemic attack. Sudden death is usually fatal arrhythmia, before the onset of life-threatening fast ventricular arrhythmias, ECG can be detected in the possible causal relationship between silent myocardial ischemia and sudden death. In addition, it was reported that 45 people sudden death in the United States each year, of which 20% to 50% died of bradyarrhythmia, before or at the same time, often accompanied by a silent myocardial ischemia. Also found the 30-year follow-up study of 5,209 cases of coronary heart disease patients, 25% of asymptomatic myocardial infarction 10 years, mortality was 84%. The results show that the rate of sudden death and mortality similar asymptomatic myocardial infarction, sudden death and mortality and myocardial infarction symptoms. Even in patients with acute myocardial infarction, still 30% of patients do not have symptoms, suggesting that residual ischemia surrounding myocardial infarction, the residual ischemia often lead to myocardial infarction and sudden death again. Medical will be asymptomatic myocardial ischemia is divided into the following three types:
Type Ⅰ, safe and silent myocardial ischemia: This type is asymptomatic, is occasionally found myocardial ischemia, it was estimated that in middle-aged men with coronary heart disease symptoms (general population) accounted for 2% to 5%. The prognosis similar to patients with angina pectoris.
Type II, asymptomatic myocardial ischemia after myocardial infarction: Although there is no angina after myocardial infarction, but that the presence of myocardial ischemia is more common. This type of patient prognosis than the type Ⅰ more adverse, especially when left ventricular dysfunction, the mortality rate of 5% to 6%.
Type III angina associated with asymptomatic myocardial ischemia: studies have shown that 70% to 80% of the patients with angina pectoris exist asymptomatic myocardial ischemia, and can occur in different types of angina. It must be pointed out that patients with unstable angina associated with silent myocardial ischemia can often cause fatal arrhythmias, myocardial ischemia exists but there is still the symptoms disappeared after treatment, this is the important indicator of poor prognosis.
Therefore, asymptomatic myocardial ischemia should arouse enough attention. It can affect the prognosis of coronary artery disease, it should be positive diagnosis and treatment.