Acute non-traumatic chest pain is a common kind of symptom in extremely critical condition, with various pathogenesis and different level of risk . Chest pain in high risk takes 1/3 of that. It mainly includes acute coronary syndrome (including myocardial infarction and unstable angina pectoris, accounted for over 95% of chest pain in high risk), aortic dissection, pulmonary embolism etc, and is in high lethality and deformity.

The investigators do the research :

1. To study the diagnosis and management condition of acute chest pain in extremely critical condition for last ten or more years in Qilu Hospital,Shandong University.
2. To discuss the significance of key accompanying symptoms(for example radiating pain, chest distress, sweating, nausea etc), physical signs and lab examination in early diagnosis and risk stratification of acute chest pain in extremely critical condition.
3. To study the effect factors of thrombus burden in STEMI patients, at the same time, creat a a simple, practical and scientific method of blood clots classification.

Inclusion Criteria:

• Inpatients of Qilu Hospital, whose electronic medical records were searched out by terms of acute myocardial infarction, aortic dissection, pulmonary embolism and unstable angina in International Classification of Diseases(ICD)-10 code from Jan.2003 to Sep.2015.

Exclusion Criteria:

• Patients whose medical records are false, omitted or uncompleted because of transference, death et al.

Patients admitted in Qilu Hospital with high risk chest pain diseases(acute myocardial infarction, aortic dissection, pulmonary embolism, unstable angina) from 2003.01 to 2015.09