Title: painless MI
题目：无痛性心肌梗塞
Author 作者: Amal Mattu

You might think that patients with painless MIs might have a better prognosis than patients with pain. Unfortunately, this is just not true.
你有可能认为无痛性心肌梗塞的病人要比有心绞痛的心梗病人的预后好。但不幸的是，这并不正确。
As many as 1/3 of patients with proven ACS have no chest pain at presentation (1). Among the more common alternative presentations (anginal equivalents) are dyspnea, diaphoresis, nausea/vomiting, and syncope/near-syncope.
接近1／3的证实有急性冠状综合症的病人在就诊时没有心绞痛（1）。其它的临床表现（与心绞痛类式的）包括呼吸困难，大汗，恶心／呕吐，和晕厥／近晕厥。
Note also that the absence of pain does not confer a better prognosis. The overall in-hospital mortality rate for patients with painless presentations is 13% vs. 4.3% for patients with chest pain.
值得注意的是，无痛并不意味着会有好的预后。总的住院期间死亡率在无痛和有痛病人中分别是13％和4.3％
A recent study (2) supported prior literature indicating that the lack of pain
is not a predictor of a more benign course, and in fact patients with painless MIs have a higher in-hospital and 1-year mortality.
一个新的研究（2）支持以前文献的观点，既缺乏疼痛并不意味着会有一个良性的过程，事实上，无痛性心肌梗塞的病人有较高的住院期间和一年死亡率。
There are several other factors that may associate lack of pain with worse outcomes (e.g. painless MIs occur more often in older patients), but regardless it's important to remember that (1) many patients with MI will present without pain, and (2) the lack of "typical" symptoms should not be reassuring.
有几个因素可能与无痛心梗和不良预后有关（如无痛心梗多发生在年纪大的病人），但不论怎样，一定要记住1）很多心肌梗塞的病人会没有心绞痛，2）没有典型的症状并不一定是好现象。

References 参考文献
(1)Brieger D, et al. Acute coronary syndromes without chest pain, an underdiagnosed and undertreated high-risk group: insights from the Global Registry of Acute Coronary Events.Chest 2004; 126:461-469.
(2) Cho JY, et a. Comparison of outcomes of patients with painless versus painful ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention. Am J Cardiol 2012;109:337-343.