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For the Chapter in the Schwinghammer, Handbook (not Wells Handbook anymore) please go to Chapter 5, Acute Coronary Syndrome.


The following updates were made to this chapter on October 9, 2020

  • Updated the hyperlinks to the Preclass activities

  • Corrected a formatting error ion Table 33-2 (adverse effects column for calcium channel blockers

  • Abixibimab was discontinued from the market and references to this drug was removed throughout the text and Table 33-5

  • Clarified when platelet function testing may be considered during de-escalation of DAPT therapy based on the 2019 Updated Expert Consensus Statement on Platelet Function and Genetic Testing for Guiding P2Y12 Receptor Inhibitor Treatment in PCI

  • Added information about the ISAR-REACT 5 study to the Ticagrelor section

  • Added enalapril dosing to Table 33-8

  • Revised Figure 33-2 to reflect current guideline-recommended duration of beta-blockers



  • imageThe predominant cause of acute coronary syndrome (ACS) in more than 90% of patients is the acute rupture, fissure, or erosion of an unstable atherosclerotic plaque followed by subsequent thrombus formation that impairs distal blood flow resulting in acute myocardial ischemia.

  • imagePatients with symptoms of myocardial ischemia suspected of having ACS should undergo risk stratification that incorporates their past medical history, presenting signs and symptoms, 12-lead electrocardiogram (ECG), and cardiac troponin (cTn); dynamic elevation in serial cTn values confirms the diagnosis of myocardial infarction (MI).

  • imageIntravenous (IV) nitroglycerin (NTG) should be considered to alleviate anginal pain and/or treat acute comorbidities such as uncontrolled hypertension (HTN) or heart failure (HF), oxygen should be administered to patients with hypoxia (oxygen saturation less than 90% [0.90]), and IV morphine may be considered in patients with refractory anginal pain.

  • imageIn the absence of contraindications, an oral β-blocker should be initiated for all patients with ACS and continued for at least 1 and up to 3 years or more to reduce the risk of major adverse cardiac events (MACE); calcium channel blockers (CCBs) may be considered in patients with vasospasm and those refractory to or with contraindications or intolerance to β-blockers.

  • imageReperfusion of the infarct-related artery in ST-segment elevation myocardial infarction (STEMI) with primary percutaneous coronary intervention (PCI) within 90 minutes of first medical contact is preferred to fibrinolytic therapy, which should be considered if primary PCI cannot be performed within 120 minutes of presentation.

  • imageAntiplatelet therapy is a central component to the acute and chronic management of patients with ACS to reduce MACE, frequently includes aspirin plus a P2Y12 inhibitor, and requires careful attention paid to the clinical scenario to select the regimen that optimizes efficacy and safety.

  • imageUse of parenteral anticoagulant agents (unfractionated heparin [UFH], low-molecular-weight heparin [LMWH], fondaparinux, bivalirudin) during hospitalization have the ability to reduce MACE in patients with ACS and requires knowledge of the diagnosis, selected management strategy, and other factors to select the drug ...

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