Acute Coronary Syndrome: Likelihood Ratios
Introduction: ACS is distinguished from stable angina by:
* Rest angina, which is usually more than 20 minutes in duration
* New onset angina that markedly limits physical activity
* Increasing angina that is more frequent, longer in duration, or occurs with less exertion than previous angina
ACS is divided into 3 major categories, namely unstable angina (defined by no serum marker elevation), NSTEMI (serum markers but no ST elevations), and STEMI.
STEMI (ST-segment Elevation Myocardial Infarction, aka ST-elevation MI) - Strict ECG definition: New ST elevation at the J-point in two contiguous leads with the cut-off points: >=0.2 mV in men or >=0.15 mV in women in leads V2-V3 and/or >=0.1 mV in other leads, in the absence of LVH and RBBB.
Cardiac Enzymes timecourse (sens/spec data) from Circulation PMID 10190875:
Cardiac Enzymes timecourse, from UpToDate:
|Population / Calculator||Prevalence||Comments / Study / Link|
|TIMI risk score||12%||http://www.mdcalc.com/uanstemitimiscore
|patients presenting to the ED with chest pain, initially normal EKG and no history of unstable angina||9.1%||Acad Emerg Med. 2002 Mar;9(3):203-8. PMID: 11874776|