SIGNS AND SYMPTOMS 
History
- Chest pain:
- Substernal pressure, heaviness, tightness, burning or squeezing
- Radiates to neck, jaw, left shoulder, or arm
- Poorly localized, visceral pain
- Anginal equivalents include:
- Symptoms usually reproduced by exertion, eating, cold exposure, emotional stress
- Symptoms not usually positional or pleuritic
- Usually relieved with rest or nitroglycerin
- Relief with nitroglycerin in nondiagnostic
- Lasts more than a few minutes but < 20 min
- Considered stable angina if no changes in pattern of frequency of symptoms
Geriatric Considerations
- Women, diabetics, ethnic minorities, and those > 65 yr often present with atypical symptoms
- Prognosis is worse for people with atypical symptoms
Physical Exam
- "Levine Sign": Clenched fist over chest, classic finding
- BP often elevated during symptoms
- Physical exam often uninformative
- occasional S3/S4,
- mitral regurgitation or new murmur (papillary muscle dysfunction)
- diminished peripheral pulses
ESSENTIAL WORKUP
ECG:
- Standard 12 lead
- Ideally should be obtained and read within 10 min of presentation for patients with acute chest pain
- Mostly helpful in detecting acute MI, less so UA
- Compare to prior ECG if available
- If normal or unchanged, serial ECGs every 10–30 min
- New ST changes or T-wave inversion suspicious for UA
- T-wave flattening or biphasic T-waves
- ≤1 mm ST depression 80 msec from the J point, is characteristic in UA
- Can see evidence of old ischemia, strain or infarct, such as old TWI, Q-wave, ST depression
- Single ECG for acute MI is about 60% sensitive and 90% specific
- ECG can also be helpful to diagnose other causes of chest pain
- Pericarditis: Diffuse ST elevations, then TW inversions and pulse rate depression
- Pulmonary embolus S1Q3T3 pattern, unexplained tachycardia and signs of right heart strain
ALERT
- Patients with normal or nonspecific ECGs have a 1–5% incidence of AMI and 4–23% incidence of UA
DIAGNOSIS TESTS & INTERPRETATION
Lab
- For stable angina, cardiac enzymes not indicated, but if history suspicious for acute MI, should obtain.
- CK-MB and troponin I or T
- < 50% of patient with UA will have low level troponin elevations
- CK-MB peaks 12–24 hr, return to baseline in 2–3 days
- Troponin peaks in 12 hr, return to baseline 7–10 days
- Hematocrit (anemia increases risk of ischemia)
- Coagulation profile
- Electrolytes, especially Cr and K+
Imaging
- CXR:
- Coronary CTA:
- Good for low-risk patients with no known CAD to rule out ischemia as cause of pain in patient if no coronary stenosis
- "Triple rule-out" for ACS, PE, and aortic dissection
- Bedside echo: To detect wall motion abnormalities and other etiologies of shock, pericardial effusion, pneumothorax
- Technetium Tc-99 sestamibi (rest): Radionucleotide whose uptake by myocardium is dependent on perfusion
Diagnostic Procedures/Surgery
- Exercise stress testing:
- Not appropriate if active chest pain with moderate to high likelihood of ischemia
- Imaging stress test (sestamibi, thallium, or echo) if baseline ECG abnormalities
- Early positive (within 3 min) concerning for UA
- Coronary angiography:
- Gold standard of diagnosis for CAD
DIFFERENTIAL DIAGNOSIS
[Outline]
PRE-HOSPITAL
- IV access
- Aspirin
- Oxygen
- Vital signs and oxygen saturation
- Cardiac monitoring
- 12-lead ECG, if possible
- Sublingual nitroglycerin
INITIAL STABILIZATION/THERAPY
- IV access
- Oxygen
- Cardiac monitoring
- Vital signs and continuous oxygen saturation
ED TREATMENT/PROCEDURES
- All patients with chest pain in which cardiac ischemia is a consideration should receive an aspirin upon arrival to the ED
- Sublingual nitroglycerin: If symptoms persist after 3 sublingual doses, suggestive of UA, AMI, or noncardiac etiology
- Pain control
- Anticoagulation
MEDICATION
First Line
- Aspirin: 325 mg PO (chewed) or 81 mg × 4 (chewed)
- In patients with aspirin allergy: Clopidogrel (Plavix) 300–600 mg PO, also consider prasugrel 60 mg PO or 180 mg PO ticagrelor
- Dual antiplatelet therapy should be given to patients with UA at medium to high risk who have been selected to have invasive strategy such as catheterization or surgery
- Nitroglycerin:
- 0.4 mg sublingual
- 5–10 µg/min IV USE NON-PVC tubing, titrating to effect
- 1–2 in of nitro paste
- Hold for low BP (can severely drop BP)
- Beware if pt has history of erectile dysfunction and use of phosphodiesterase inhibitors like sildenafil (Viagra) or tadalafil (Cialis) can last 48 hr
- Morphine
- Consider beta blocker
- Metoprolol: 25—50 mg PO or 5 mg IV q5–15min for refractory HTN and tachycardia
- Contraindicated in reactive airway disease, active CHF, bradycardia, hypotension, heart block, cocaine use
- Does not necessarily need to be given while patient is in ED, suggested benefit within 24 hrs of AMI
Second Line
Anticoagulation
- Does not alter mortality
- Consider conferring with cardiology prior to anticoagulation
- Heparin: 60 U/kg IV bolus, then 12 U/kg/hr (goal PTT 50–70)
- Enoxaparin: 1 mg/kg SC q12 or q24 if Cr clearance < 30mL/min
- Glycoprotein IIb/IIIa inhibitors: Primary benefit en route to cath
- Eptifibatide (Integrilin): 180 µg/kg bolus IV over 1–2 min, then 2 µg/kg/min up to 72 hr
- Tirofiban (Aggrastat): 0.4 µg/kg/min for 30 min, then 0.1 µg/kg/min for 48—108 hr
- Abciximab (Reopro): 0.25 mg/kg IV bolus, then 0.125 µg/kg/min, maximum dose 10 µg/min for 12 hr
- Bilvalirudin, fondaparinux
- Patients at risk for high risk for bleeding include the elderly, female, anemic, chronic renal failure
[Outline]
DISPOSITION
Admission Criteria
- Patients with UA require admission to the hospital
- Early intervention with cardiac catheterization likely decreases mortality in patients with elevations in cardiac enzymes, persistent angina or hemodynamic instability
- Patients with unclear diagnosis likely would benefit from admission to ED observation unit or hospitalization for serial cardiac enzymes, ECG and stress testing/catheterization
Discharge Criteria
- Patients with stable angina
- Patients who are enzyme/stress testing or cath negative
FOLLOW-UP RECOMMENDATIONS
Patients with stable angina or workup negative chest pain should follow up with their PCP or cardiologist within several days of ED visit.
[Outline]
- 2012 Writing Committee Members, Jneid H, Anderson JL, et al. 2012 ACCF/AHA focused update of the guideline for the management of patients with unstable angina/Non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 focused update): a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. Circulation. 2012;126(7):857–910.
- Marx JA, Hockberger RS, Walls RM, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, PA: Mosby Elsevier; 2010.
- Mistry NF, Vesely MR. Acute coronary syndromes: From the emergency department to the cardiac care unit. Clinics. 2012;30:617–627.
- Swap C, Nagurney JT. Value and limitations of chest pain history in the evaluation of patients with suspected acute coronary syndromes. JAMA. 2005;294:2623–2949.
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