Acute Coronary Syndrome


  • Suspect ACS in these three presentations
    • 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
  • Subtypes of ACS
    • STEMI
    • NSTE-ACS
      • NSTEMI
        • Elevated troponin in absence of ST elevation
      • Unstable Angina (<4% ACS have normal biomarkers and EKG)
        • New onset angina should be considered as unstable

Types of MI

  • 1 = Spontaneous plaque rupture and thrombus
  • 2 = Ischemic imbalance
  • 3 = Sudden death (biomarkers unavailable)
  • 4 = PCI/stent-related
  • 5 = CABG-related


  • Increase risk
    • Radiation to both arms > right arm > left arm
    • Diaphoresis
    • Vomiting
    • Worse on Exertion
  • Decrease risk (Note: 7% of patients will have pleuritic chest pain and chest pain reproduced on palpation -> Atypical is common!)
    • Reproduced on chest wall palpation (tenderness)
    • Pleuritic pain
    • Sharp/stabbing
    • Positional
  • Onset of pain
  • Contraindications to
    • Thrombolysis (see bottom of page)
    • Anticoagulation (eg. currently on anticoagulation)
    • Nitroglycerin (eg. PDE5-i, eg. Viagra)
    • Metoprolol (eg. cocaine)
  • Allergy to medications (eg. Aspirin)


  • ABC
  • Vitals
  • Cardiac/oxygen monitor and IV x2
  • Oxygen for sat >90%
  • Focused history (AMPLE), include above
  • Focused physical exam
    • Rule out cardiogenic shock (hypotension, poor perfusion)
    • Rule out heart failure (S3/S4, edema, distended liver)
  • 12-lead ECG (repeat if non-diagnostic)
  • Consider CXR (r/o pneumothorax, pneumonia, aortic dissection, esophageal rupture)
  • Initial Troponin with repeat (3h for highly sensitive assay or 6h for sensitive assay from onset of chest pain)
    • Only 1 Troponin needed if isolated CP >12hrs prior to ED visit and are symptom free for 12hrs prior to their ED visit
  • Emergent cardiogenic consultation if shock, heart failure, sustained V Tach
  • Aspirin (non-EC) 325mg PO chew or by rectum if unable to take PO
  • Labs: CBC, Trop, Chem 10 (K, Mg), INR
  • If stable
    • *If chest pain, no hemodynamic compromise (RV infarct), and no PDE5i, Nitroglycerin 0.4mg (or 1 spray) SL q5mins x3
    • *If no heart failure/hemodynamic compromise/bradycardia/severe asthma/cocaine, Metoprolol 25mg PO
    • Consider Fentanyl 25mcg IV or Morphine 2.5mg IV q5 mins (for severe pain, avoid if possible)
  • Atorvastatin 80mg PO daily


  • Compare with previous
  • If suspicious, consider Serial EKG q10-15mins and URGENT formal echocardiography by cardiologist (r/o wall motion abnormalities suggestive of MI)
  • STEMI (or equivalent need for urgent repurfusion)
    • ST segment elevations at J point in 2 contiguous leads >1mm in all leads except V2 and V3
      • Men <40yo, ≥2.5 mm in V2 and V3
      • Men >40yo, ≥2 mm in leads V2 and V3
      • Women ≥ 1.5 mm ST elevation in V2 and V3
  • Non-STEMI
    • ST segment depressions or deep T wave inversions without Q waves or no ECG changes
  • Unstable Angina
    • No EKG changes

Risk of Treatment

  • CRUSADE risk of bleeding post-MI
    • Consider less invasive treatment in STEMI/NSTEMI with high risk of bleeding

STEMI or Equivalent

  • Reperfusion + Dual antiplatelet + Anticoagulant
    • Primary PCI (within 90 mins of medical contact) + Ticagrelor 180mg + UFH 50-70 units/kg IV (max 5000 units)
      • If PCI unavailable, <120mins of first medical contact, <12h symptom onset (unless ongoing symptoms), no contraindications (see at bottom of page)
        • Fibrinolysis (goal 30mins) + Clopidogrel 300mg (75mg if age ≥ 75) + anticoagulation [Enoxaparin 30mg IV (adjust for renal and age ≥ 75) or UFH (if possible PCI later)]
  • If no reperfusion indicated >12h onset of symptoms for Fibrinolysis or >24h for PCI, start Ticagrelor 180mg + Enoxaparin or UFH
  • Glycoprotein IIb/IIIa Inhibitors [eg. Abciximab (Reopro), Eptifibatide (Integrilin), Tirofiban (Aggrastat)] may be given in high risk patients or continued ischemia as determined by the treating cardiologist

NSTEMI or Unstable Angina

  • Consider dual antiplatelet (Ticagrelor 180mg) + anticoagulant (enoxaparin or heparin if possible PCI later) for confirmed ACS with high risk of recurrent ischemia
  • Consider PCI +/- GP IIb/IIIa inhibitor, especially in evidence of persistent ischemia (pain or EKG changes)
  • No evidence for fibrinolysis

Low Risk (unlikely ACS)


  • Lifestyle changes
    • Modifiable risk factors (DLP, HTN, DM)
    • Stop smoking
    • Weight management
    • Physical activity (Consider rehab)
  • Medications
    • ASA 81mg (or Clopidogrel 75mg if ASA intolerance)
      • May consider dual antiplatelet therapy in subset (stent)
      • May consider low-dose rivaroxaban 2.5mg PO BID with aspirin in very high risk CV events with low risk bleeding
    • High-intensity Statin (eg. Rosuvastin 20-40mg daily, Atorvastatin 80mg daily)
    • ACEI (or ARB), especially if anterior MI, heart failure or LVEF ≤40%
    • Beta-blocker, especially if heart failure or LVEF ≤40%
      • Consider switch to longer-acting (eg. Bisoprolol 2.5-20mg PO daily to maintain HR<70 and sBP>90mmHg)
  • Monitor for post-MI complications
    • Pericarditis (10%)+/- pericardial effusion
      • Suspect in pleuritic chest pain, fever, leukocytosis
      • Aspirin or colchicine
      • If >4w (Dressler's Syndrome) consider NSAIDs and/or corticosteroids
    • LV free wall rupture (3%)
    • VSD (1-2%)
    • Papillary muscle rupture (1%)


Absolute contraindications

  • History of any intracranial hemorrhage
  • History of ischemic stroke within three months (unless acute ischemic stroke seen within three hours, which may be treated with thrombolytic therapy)
  • Presence of a cerebral vascular malformation or a primary or metastatic intracranial malignancy
  • Symptoms or signs suggestive of an aortic dissection
  • A bleeding diathesis or active bleeding, with the exception of menses
  • Significant closed-head or facial trauma within three months

Relative contraindications

  • Blood pressure >180 mmHg systolic and/or >110 mmHg diastolic
  • History of ischemic stroke more than three months previously
  • Dementia
  • Any known intracranial disease that is not an absolute contraindication
  • Traumatic or prolonged (>10 min) cardiopulmonary resuscitation
  • Major surgery within three weeks
  • Internal bleeding within four weeks or an active peptic ulcer
  • Noncompressible vascular punctures
  • Pregnancy
  • Current warfarin therapy
  • For streptokinase or anistreplase - a prior exposure (more than five days previously) or allergic reaction to these drugs

Causes of elevated troponin

  • Cardiac
    • Contusion/surgery/procedure
    • Infiltrative/inflammatory disease
    • Aortic dissection
    • Aortic valve disease
    • Cardiomyopathy
    • Tachyarrhthmias
  • Noncardiac
    • Extreme exertion/Rhabdomyolysis
    • Pulmonary embolism
    • Renal failure
    • CVA, subarachnoid hemorrhage
    • Critically ill (respiratory failure, sepsis)