Acute Coronary Syndromes


Acute Coronary Syndromescardiac causes of chest pain


“ACS is a constellation of signs and symptoms resulting from an imbalance between myocardial oxygen supply and demand. There are three general classifications: unstable angina, NSTEMI, and STEMI.”1

  • Unstable angina is a type of ACS with no elevation of biomarkers and no pathologic ST-segment elevation.”1
  • NSTEMI is characterized by biomarker elevation and no pathologic ST-segment elevation.”1
  • “Acute Myocardial Infarction (AMI) is characterized by ST elevation and biomarker elevation (STEMI).”1


The initial presenting complaint of chest pain can appear daunting with a wide differential diagnosis. A common approach is to determine whether the patient’s chest pain is cardiac or non-cardiac in nature. The combination of a thorough history (including risk factors), physical exam, and interpretation of investigations (ie. labs, ECGs, etc) can assist with this differentiation (ACS Risk Stratification & Low Risk Chest Pain).


Once an ACS cause of chest pain is identified a treatment and disposition strategy focusing on the type of ACS occurring is required (ACS Management, ED Management of the NSTEMI).


An in-depth review of many specific aspects of Acute Coronary Syndromes can be found in this excellent Cardiology Module and a few other (ACS Part 1 & Part 2).


Click HERE for a list of all mentioned FOAM resources.


  1. Green, G., Hill, P. Chapter 52, “Chest Pain: Cardiac Or Not”. Tintinalli’s Emergency Medicine – A Comprehensive Study Guide. J Tintinalli. 7th ed. McGraw-Hill Education, 2010. 361. Print.


Prepared by Alex Mungham PGY1 FM – University of Ottawa