II. Indications: Electrocardiogram (EKG) suggestive of Low Risk Chest Pain

  1. Normal or unchanged Electrocardiogram
  2. ST Depression 0.5 to 1.0 mm
  3. T Wave inversion (<0.2 mV) or flattening
    1. Leads with dominant R Wave

III. Contraindications: Moderate Risk patient (or other concerning findings)

  1. See Moderate Risk Acute Coronary Syndrome Management
  2. Concerning history findings
    1. Unstable Angina (low threshold or increased frequency of provoked Angina)
    2. New onset Angina
  3. Significant comorbidity
    1. Coronary Artery Disease
    2. Peripheral Vascular Disease
    3. Prior PCI (stenting) or Coronary Artery bypass (especially if in last 6 months)
    4. Heart Failure
    5. Structural heart disease (e.g. Aortic Stenosis)
    6. Pulmonary Hypertension
  4. Concerning examination findings
    1. Hemodynamic abnormalities (e.g. Hypotension)
    2. Syncope
    3. Pulmonary edema
    4. Ill appearing
  5. Concerning diagnostic findings
    1. Troponin Increased
    2. Significant EKG changes (e.g. ST segment elevation or T Wave inversion)
    3. Arrhythmia
  6. Factors that may require additional vigilence but may not absolutely contraindicate following the low risk protocol
    1. Diabetes Mellitus (especially if longstanding >10 years or uncontrolled)
    2. Typical Chest Pain (central, heavy, crushing, pressure or squeezing pain)
      1. Especially if associated with Dyspnea, diaphoresis, Nausea or Vomiting
      2. Higher risk presentation than Atypical Chest Pain (sharp, localized or lateral Chest Pain)

IV. Labs: Cardiac Biomarkers (i.e. Troponin)

  1. Highly sensitive Troponin Is sufficiently sensitive to replace all other biomarkers (e.g. CK-MB, Myoglobin, CRP)
  2. Decision rules are used by accelerated protocols to shorten time between Troponins
    1. HEART Score 0-3 (and normal first Troponin)
      1. Three hours between standard Troponins (Used by University of Maryland)
        1. http://blog.hippoem.com/2015/02/17/emrap-special-edition-a-defensible-chest-pain-adp/
      2. One normal Troponin and a HEART Score 0-3 has a risk of major adverse cardiac event rate of 1.7% at 30 days
        1. Backus (2013) Int J Cardiol 168(3):2153-8 [PubMed]
      3. Two Troponins at 3 hours apart lowers the major adverse cardiac event rate risk to <1% at 30 days
        1. Mahler (2015) Circ Cardiovasc Qual Outcomes 8(2): 195-203 [PubMed]
    2. TIMI Score 0
      1. Two hours between Troponins (Used by some centers)
      2. However TIMI Score was not intended for risk stratification in undifferentiated Chest Pain
      3. Berg and Orman in Herbert (2014) EM:Rap 14(9): 3-4
  3. Presentation >6 hours from Chest Pain onset
    1. Single Troponin Typically rules-out acute Myocardial Infarction
    2. Consider repeating serum Troponin In 4 hours if higher clinical suspicion
  4. Presentation <6 hours from Chest Pain onset
    1. Standard Troponin
      1. Obtain two Troponins 4 hours apart (or second Troponin at 6 hours from symptom onset)
      2. Alternative: Use decision rules (see above) to shorten the duration between Troponins to 2-3 hours
        1. Obtain HEART Score of 0-3 as above, and 2 normal Troponins 3 hours apart
        2. Lowers the major adverse cardiac event rate risk at 30 days to less than 1%
      3. Alternative: Patient declines a second Troponin
        1. Assumes a 1.7% major adverse cardiac event rate risk at 30 days
        2. See Disposition below
    2. Highly sensitive Troponin
      1. Obtain two Troponins 3 hours apart
  5. References
    1. Diercks (2012) Am Heart J 163(1):74-80 [PubMed]

V. Diagnostics

  1. Monitoring
    1. Vital Signs including Heart Rate and Blood Pressure
    2. Continuous ST segment monitoring
    3. Low risk patients do not require telemetry (however typically performed in standard practice)
      1. Goldman Risk Score <8% and
      2. Troponin I <0.3 ng/ml and
      3. CK-MB <5 ng/ml
      4. Hollander (2004) Ann Emerg Med 43:71-6 [PubMed]
  2. Serial Electrocardiogram (EKG)
    1. EKG Test Sensitivity is only 90% for Myocardial Infarction (normal EKG despite true MI in 10% of cases)
    2. ACS should not be excluded based on a single EKG
      1. Perform EKG at time of serial Troponins AND
      2. Perform EKG with changes in patient symptoms (e.g. increased Chest Pain)
      3. Positive examples are not uncommon of multiple (e.g. five q5-10 min) serial EKGs
        1. Ongoing Chest Pain and ischemia only on the last EKG
      4. However ACC/AHA protocols do not require more than one Electrocardiogram (EKG)
    3. EKG normal, unchanged, or nominally changed (T Wave flattening, <1 mm ST depression)
      1. Continue with the low risk protocol (see below)
    4. EKG with significant change (symmetric ST segment change >1mm, T Wave inversion >0.2 mV)
      1. Switch to Moderate Risk Acute Coronary Syndrome Management

VI. Imaging

  1. Stress Testing
    1. Precautions
      1. Test Sensitivity for Ischemic Heart Disease: 85-90% (esp if evaluation delayed from time of symptoms)
        1. Best Test Sensitivity for coronary lesions >70% (but MI may occur with 30-50% stenosis)
      2. Poor Test Specificity in low risk populations
        1. Exercise caution in stress testing low risk patients (high False Positive Rate)
    2. Tests
      1. Exercise Treadmill Test (Test Sensitivity 50-80%)
      2. Stress Echocardiogram
      3. Perfusion Radionuclide scan (SPECT, Stress Cardiolite, Test Sensitivity >90%)
        1. Negative test confers a good prognosis for the next 12 months
        2. Positive test is highly predictive of major adverse cadiac events
      4. Pharmacologic Stress Test (e.g. Lexiscan)
  2. Resting Echocardiogram (for wall motion abnormality)
    1. Efficacy is typically not sufficient to rule-in or rule out ACS
    2. Does not distinguish between old and new Myocardial Infarction
    3. Decreased Test Sensitivity if patients present after symptom resolution
  3. Coronary CT Angiogram (CTCA)
    1. Indications
      1. Single elevated or equivocal serum Troponin without other findings of ischemia
      2. Alternative to stress test per 2007 AHA guidelines in low to intermediate risk patients
    2. May decrease Chest Pain admission rates
    3. May provoke greater intervention rate (due to false positives)
    4. Increased radiation exposure and intravenous radiographic contrast load
    5. Test efficacy for coronary ischemia decreases with Triple Screen (ACS, PE, Aortic Dissection)
  4. Angiography
    1. Indicated for high suspicion cases such as unequivocally positive ekg or cardiac biomarker for ischemia
  5. References
    1. Orman, Mattu and Swaminathan in Herbert (2016) EM:Rap 16(10): 8-9
    2. (2016) J Am Coll Radiol 13(2): e1-29 +PMID:26810814 [PubMed]

VII. Evaluation

  1. Initial evaluation for high risk, intermediate risk and Low Risk Chest Pain begins the same
    1. See Acute Coronary Syndrome Immediate Management (includes giving Aspirin 325 mg)
    2. Low Risk Chest Pain protocol is only per indications listed above
  2. Approach
    1. Assess Angina Diagnosis likelihood
    2. Consider Chest Pain differential diagnosis
  3. Decision Rules
    1. See Chest Pain Decision Rules
    2. HEART Score (may be preferred for Chest Pain accelerated diagnostic protocols)
    3. TIMI Risk Score
    4. GRACE Score
    5. See Goldman Risk Score
  4. Precautions
    1. Cardiac Risk Factors are not useful in the exclusion of acute coronary disease in the emergency department
      1. Despite the evidence, Cardiac Risk Factors are included in most decision rule calculators
      2. Body (2008) Resuscitation 79(1): 41-5 [PubMed]
      3. Patel (2000) West J Med 173(6): 423-4 [PubMed]

VIII. Management: Patient triage based on findings

  1. Findings suggestive of Myocardial Ischemia or NSTEMI (e.g. EKG change or Troponin Increase)
    1. See Moderate Risk Acute Coronary Syndrome Management
    2. See Myocardial Ischemia Protocol
    3. Consider MI Adjunctive Therapy
  2. Findings without signs of ACS or Myocardial Ischemia
    1. High risk for adverse event in near future (based on decision rules listed above)
      1. See Myocardial Ischemia Protocol
      2. Treat same as signs of Myocardial Ischemia above
    2. Intermediate risk for adverse event in near future
      1. Consider early discharge with stress testing within 72 hours (see protocol below)
      2. Consider Stress Imaging prior to discharge (See imaging above)
      3. Consider admission to Chest Pain unit
    3. Low risk for adverse event in near future (TIMI Score 0 or HEART Score <3)
      1. Discharge from Emergency Department
      2. Close follow-up with primary physician
      3. Discuss warning signs
      4. Discuss Chest Pain differential diagnosis
      5. Consider outpatient Exercise Stress Testing
        1. Stress testing is not required in very low risk patients (e.g. TIMI Score 0)
        2. Stess testing is unlikely beneficial if same modality (e.g. cardiolite) done in prior 6-12 months

IX. Management: Early disposition of an intermediate risk patient (of low risk protocol)

  1. Indications
    1. Intermediate risk for adverse event in near future (see above)
      1. Patient has Cardiac Risk Factors, but is risk stratified to low risk protocol
    2. Patient risk based on HEART Score, TIMI Risk Score, GRACE Score, Vancouver Chest Pain Rule or Goldman Risk Score
      1. Protocol below assumes a TIMI score of 0 or a HEART Score of 0-3
  2. Exclusion criteria
    1. See contraindications listed above
    2. Follow Moderate Risk Acute Coronary Syndrome Management instead if any are true
    3. Unreliable patient
    4. Hypotension with systolic Blood Pressure <110
    5. Congestive Heart Failure
    6. Pulmonary rales
    7. Known previous Myocardial Infarction
    8. Worsening Angina
    9. Positive Troponin
    10. Significantly abnormal Electrocardiogram (symmetric ST segment change >1mm, T Wave inversion >0.2 mV)
    11. Other criteria met for Moderate Risk Acute Coronary Syndrome Management
  3. Evaluation
    1. See diagnostics above including monitoring and cardiac biomarker (Troponin) timing
  4. Disposition (based on protocol listed above under labs)
    1. Contraindications
      1. Exclusion criteria met
    2. Protocol
      1. Confirm patient hemodynamically stable with negative Troponins and no exclusion criteria present
      2. Discharge to home with precautions, Nitroglycerin and close interval follow-up
      3. Outpatient stress test within 72 hours (per AHA despite rationale below)
        1. Stress test timing within 72 hours is controversial
        2. Some argue removing the time stipulation (as has been done in Europe)
    3. Education
      1. Alert the patient that you are still concerned about their heart
        1. Cannot fully exclude Angina in the Emergency Department
      2. Warn the patient
        1. Return to the Emergency Department for changes or worsening ("listen to your body")
      3. Discuss with patient the overall risk of cardiovascular event before work-up complete
        1. Between early emergency department discharge and stress testing within 72 hours
      4. For every 100 people with lower risk Chest Pain
        1. Adverse Event: 2 had a heart or pre-heart attack within 45 days
        2. No Adverse Event: 98
      5. Patient is given choice
        1. Choices from the University of Maryland protocol (see links below)
          1. Based on a TIMI score or 0, or a HEART Score of 0-3
        2. I would like a repeat Troponin blood test (e.g. in 3 hours)
          1. If the Troponin blood test is negative I will be discharged for follow-up
          2. I understand my risk of heart attack or heart complications is <1% in the next 30 days
          3. I will see either my primary care doctor or cardiologist for follow-up
        3. I would like to be placed in observation for further testing
          1. This testing may include urgent cardiac stress testing
          2. I understand this may increase the cost of my evaluation
          3. I understand this may increase the duration of my emergency stay
        4. I will decline a repeat Troponin blood test (e.g. in 3 hours)
          1. I will see either my primary care doctor or cardiologist for follow-up
          2. I understand my risk for a heart attack or heart complications is ~2% in the next 30 days
      6. Consider demonstrating this in the form of a graphical card
        1. http://circoutcomes.ahajournals.org/content/5/3/251.figures-only
      7. References
        1. Hess (2012) Circ Cardiovasc Qual Outcomes 5(3): 251-9 [PubMed]
    4. Rationale
      1. Risk of short-term Myocardial Infarction or death in this cohort is less than 1%
        1. Hamm (1997) N Engl J Med 337(23): 1648-53 [PubMed]
        2. Weinstock (2015) EM:Rap 175(7): 1207-12 [PubMed]
      2. Stress testing does not effectively risk stratify this low risk cohort further
        1. Kosowsky (2011) Emerg Med Clin North Am 29(4): 721-7 [PubMed]
      3. Hospital observation is not without risk
        1. Overall risk of in-hospital death due to iatrogenic complication is as high as 1 in 160
          1. James (2013) J Patient Saf 9(3): 122-8 [PubMed]
      4. Positive stress testing in low risk patients does not improve outcomes
        1. No intervention was done in 90% of low risk patients with a positive stress test
          1. Penumetsa (2012) Arch Intern Med 172(11):873-7 [PubMed]
        2. Low risk patients who undergo PCI have worse outcomes
          1. Hoenig (2010) Cochrane Database Syst Rev (3): CD004815 [PubMed]
          2. Swahn (2012) European Heart Journal 33(1):51-60 [PubMed]
      5. Missed acute cardiac ischemia, NSTEMI or Unstable Angina in low risk patients
        1. Does not significantly impact outcomes
        2. Pope (2000) N Engl J Med 342(16): 113-70 [PubMed]
        3. Montelescot (2009) JAMA 302(9):947-54 [PubMed]
      6. Chest Pain units are often used because of availability, but may not be indicated
        1. Up to 50% of patients admitted to Chest Pain unit would have been discharged if not available
        2. Blecker (2016) Ann Emerg Med 67(6): 706-13 +PMID: 26619756 [PubMed]
  5. References
    1. Newman, Shreves and Weingart in Majoewsky (2012) EM:Rap 12(11): 5-7
    2. Berg and Orman in Herbert (2014) EM:Rap 14(9): 3-4

X. References

  1. Avellino (2014) Crit Dec Emerg Med 28(2): 2-9
  2. Orman and Mattu in Herbert (2017) EM:Rap 17(2): 9-11
  3. Hollander (2016) Circulation 134(7): 547-64 +PMID:27528647 [PubMed]

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Ontology: Atypical chest pain (C0262384)

Concepts Sign or Symptom (T184)
SnomedCT 139236003, 102589003
English atypical chest pain, atypical chest pain (diagnosis), Atypical chest pain, Atypical chest pain (finding)
Spanish dolor de pecho atípico (hallazgo), dolor de pecho atípico

Ontology: Electrocardiogram abnormal (C0522055)

Concepts Finding (T033)
SnomedCT 207459003, 102594003, 142015008, 158649004, 164855004
English ECG ABNORMAL, ECG abnormal, ECG electrocardiogram abn., Electrocardiogram (ECG) abnormal, [D]Electrocardiogram (ECG) abnormal (context-dependent category), [D]ECG electrocardiogram abn., [D]Electrocardiogram (ECG) abnormal, Abnormal EKG, abnormal ECG, abnormal electrocardiogram (diagnosis), electrocardiographic abnormality, abnormal EKG, abnormal electrocardiogram, ECG abnormal NOS, ECG EKG abnormal (NOS), EKG abnormal, Electrocardiogram abnormal (NOS), Electrocardiogram abnormal NOS, Disorder ECG/EKG (NOS), Electrocardiogram abnormal (finding), Abnormal EKG finding, Abnormal ECG, Electrocardiogram abnormal, Abnormal ECG (finding), Electrocardiographic abnormalities, abnormal ecg, abnormal ekgs, abnormal ekg, abnormal ekg findings, abnormal electrocardiograms, ekg abnormal, [D]Electrocardiogram (ECG) abnormal (situation), ECG abnormal (finding), Electrocardiographic abnormality, electrocardiogram; abnormal, abnormal; electrocardiogram, Abnormal electrocardiogram, Disorder electrocardiogram (NOS)
Italian Elettrocardiogramma anormale, Elettrocardiogramma anormale (NAS), Elettrocardiogramma anormale, NAS, ECG anormale, ECG anormale, NAS, ECG anormale (NAS), Alterazione dell'ECG (NAS)
Dutch stoornis ECG (NAO), ECG abnormaal (NAO), ECG abnormaal, ECG abnormaal NAO, elektrocardiogram abnormaal NAO, abnormaal ECG, elektrocardiogram abnormaal (NAO), abnormaal; elektrocardiogram, elektrocardiogram; abnormaal, elektrocardiogram abnormaal
French Perturbation à l'ECG/EKG SAI, ECG anormal, ECG anormal SAI, Electrocardiogramme anormal SAI, ECG EKG anormal SAI, EKG anormal, ANOMALIE DE L'ECG, Électrocardiogramme anormal
German anomales EKG, Stoerung EKG (NNB), EKG anomal (NNB), Elektrokardiogramm anomal (NNB), EKG anomal, EKG anomal NNB, Elektrokardiogramm anomal NNB, EKG ABWEICHUNG, Elektrokardiogramm anomal
Portuguese ECG anormal, ECG anormal NE, Electrocardiograma anormal NE, Alteração do ECG (NE), ECG ANORMAL, Electrocardiograma anormal
Spanish Trastorno de ECG (NEOM), ECG anormal (NEOM), Electrocardiograma anormal (NEOM), ECG anormal NEOM, Electrocardiograma anormal NEOM, [D]electrocardiograma anormal (categoría dependiente del contexto), ECG, ALTERACION, hallazgo anormal en el ECG, hallazgo anormal en el electrocardiograma, hallazgo anormal en el ECG (hallazgo), hallazgo anormal en el electrocardiograma (hallazgo), [D]electrocardiograma anormal, [D]ECG anormal, electrocardiograma anormal, electrocardiograma anormal (hallazgo), ECG anormal, [D]electrocardiograma anormal (situación), hallazgo electrocardiográfico anormal, Electrocardiograma anormal
Japanese ECG/EKG異常(NOS), ECG異常, 異常EKG, 心電図異常, 心電図異常(NOS), ECG異常NOS, EKG異常, 心電図異常NOS, ECGイジョウNOS, イジョウEKG, EKGイジョウ, シンデンズイジョウ, ECGイジョウ, ECGEKGイジョウNOS, シンデンズイジョウNOS
Czech EKG abnormální, Elektrokardiogram abnormální (NOS), Elektrokardiogram abnormální, Abnormální EKG NOS, Abnormální elektrokardiogram, Elektrokardiogram abnormální NOS, Poruchy na EKG (NOS), Abnormální EKG, Abnormální elektorkardiogram (NOS)
Hungarian EKG-eltérés k.m.n., EKG kóros k.m.n., EKG kóros, Elektrokardiogram kóros k.m.n., Elektrokardiogram kóros, Kóros EKG

Ontology: Acute Coronary Syndrome (C0948089)

Definition (MSH) An episode of MYOCARDIAL ISCHEMIA that generally lasts longer than a transient anginal episode that ultimately may lead to MYOCARDIAL INFARCTION.
Definition (NCI_CTCAE) A disorder characterized by signs and symptoms related to acute ischemia of the myocardium secondary to coronary artery disease. The clinical presentation covers a spectrum of heart diseases from unstable angina to myocardial infarction.
Definition (NCI) Signs and symptoms related to acute ischemia of the myocardium secondary to coronary artery disease. The clinical presentation covers a spectrum of heart diseases from unstable angina to myocardial infarction.
Concepts Disease or Syndrome (T047)
MSH D054058
SnomedCT 393587009, 394659003
Japanese 急性冠動脈症候群, キュウセイカンドウミャクショウコウグン
English Coronary Syndromes, Acute, Syndromes, Acute Coronary, Acute Coronary Syndromes, Acute Coronary Syndrome, Syndrome, Acute Coronary, Coronary Syndrome, Acute, Acute Coronary Syndrome [Disease/Finding], acute coronary syndromes, syndrome acute coronary, acute coronary syndrome (diagnosis), acute coronary syndrome, Acute coronary syndrome, Acute coronary syndrome (disorder), ACS - Acute coronary syndrome
Portuguese Síndrome Coronariana Aguda, Síndrome coronário agudo
Spanish Síndrome Coronario Agudo, síndrome coronario agudo (trastorno), síndrome coronario agudo, Síndrome coronario agudo
Finnish Akuutti sepelvaltimo-oireyhtymä
German Akutes Koronarsyndrom, akutes Koronarsyndrom
Italian Sindrome coronarica acuta
Russian KORONARNYI SINDROM OSTRYI, КОРОНАРНЫЙ СИНДРОМ ОСТРЫЙ
Swedish Akut koronarsyndrom
Czech Akutní koronární syndrom, akutní koronární syndrom
French Syndrome coronaire aigu, SCA (Syndrome Coronarien Aigu), Syndrome coronarien aigu
Polish Zespół wieńcowy ostry
Hungarian Acut coronaria syndroma
Norwegian Akutt koronarsyndrom, Koronarsyndrom, akutt, AKS
Dutch acuut coronairsyndroom