Chest Pain

Triage and Diagnostic Approach to Chest Pain in Emergency Settings

Topic: Chest Pain

1. Topic Overview

Chest pain is a critical clinical presentation and one of the most common reasons for Emergency Department (ED) visits, accounting for roughly 5-10 million encounters annually in the United States ^[5]. While the etiology is frequently benign (e.g., musculoskeletal, gastroesophageal reflux), the Primary Care and Emergency FNP must systematically rule out life-threatening causes. The high-yield focus of any exam or clinical encounter is the rapid identification and management of Acute Coronary Syndrome (ACS), Aortic Dissection, Pulmonary Embolism (PE), and Cardiac Tamponade.

Why it matters: Board exams (AANP/ANCC) will heavily test immediate triage decisions, interpretation of early diagnostic data (EKG, Troponin), and adherence to AHA/ACC guideline-directed management protocols ^[1].

2. Key Concepts and Definitions

• Acute Coronary Syndrome (ACS): An umbrella term for conditions caused by sudden reduced blood flow to the heart muscle. Includes:
  • STEMI: ST-Elevation Myocardial Infarction (complete vessel occlusion).
  • NSTEMI: Non-ST-Elevation Myocardial Infarction (partial/incomplete occlusion).
  • Unstable Angina: Ischemic symptoms without elevated cardiac biomarkers.
• Cardiac Biomarkers: High-sensitivity cardiac troponin (hs-cTn) I or T is the gold standard for detecting myocardial injury^[2]. CK-MB is less specific but can be used if troponin is unavailable.
• Risk Stratification Scores: Clinical tools used to predict 30-day major adverse cardiac events (MACE). The HEART Score (History, EKG, Age, Risk factors, Troponin) is the most validated for use in the Emergency Department and Urgent Care settings^[3].

3. Core Principles: The Initial Assessment

1. Stability Assessment (Primary Survey): Assess ABCs immediately. Is the patient hemodynamically stable? Are they in cardiogenic shock or respiratory distress?
2. Focused History (OPQRST + SAMPLE):
   • Onset: Sudden vs. gradual.
   • Provocation/Palliation: Exertional? Relieved by rest/NTG?
   • Quality: Pressure, tearing, sharp, stabbing.
   • Region/Radiation: Chest, jaw, left arm, back, epigastric.
   • Severity: 0-10 scale.
   • Timing: Constant vs. intermittent, duration.
3. Targeted Physical Exam:
   • Vital signs (including bilateral BPs).
   • Cardiac auscultation (S3 gallop, murmurs, pericardial rub).
   • Pulmonary auscultation (rales indicating pulmonary edema).
   • Signs of JVD or peripheral edema.

4. Signs, Symptoms, and Clinical Features

5. Assessment, Diagnosis, and Evaluation

The goal of the FNP is to identify or exclude lethal causes within the first 10 minutes of patient contact.

• 12-Lead EKG: Must be obtained and interpreted within 10 minutes of arrival for any patient with chest pain ^[1].
  • Look for STEMI criteria (ST elevation at the J point in 2 contiguous leads: ≥2mm in men or ≥1.5mm in women in V2-V3, or ≥1mm in other leads).
  • Identify mimics: LVH with strain, Wellen's signs (critical LAD stenosis), S1Q3T3 (PE), diffuse PR depression/ST elevation (Pericarditis).
• High-Sensitivity Troponin (hs-cTn): Serial testing at 0 and 3 hours (or 0/1/2 hour protocols) is standard. A single negative troponin is insufficient to rule out MI^[2].
• Chest X-Ray (CXR): Helps identify widened mediastinum (dissection), pneumothorax, pneumonia, or pulmonary edema.
• Risk Stratification (HEART Score):
  • Points are assigned for History, EKG, Age, Risk factors, and Troponin (0-2 points each).
  • Score 0-3: Low risk (2% MACE rate). Candidate for early discharge/stress test.
  • Score 4-6: Moderate risk (20% MACE rate). Observation admission.
  • Score 7-10: High risk (72% MACE rate). Invasive management recommended ^[3].

6. Treatment, Interventions, and Patient Care

Acute Management of Suspected ACS

1. Oxygen: Only if O2 sat is <90% or signs of respiratory distress (Avoid routine O2 in normoxic patients).
2. NTG (Nitroglycerin): 0.4mg SL q5min x 3 for ongoing pain. Contraindications: SBP <90, HR <50 or >100, suspected RV infarct, or PDE5 inhibitor use (e.g., Viagra, Cialis) within 24-48 hours.
3. Morphine: 2-4mg IV for pain refractory to NTG. Use with caution; can mask symptoms and depress respirations.
4. Aspirin: 324 mg chewed immediately (non-enteric coated).
5. P2Y12 Inhibitor: Ticagrelor 180 mg loading dose (or Clopidogrel 600 mg if ticagrelor is unavailable).
6. Anticoagulation: Unfractionated Heparin bolus + drip (or LMWH).
7. High-Intensity Statin: Atorvastatin 80 mg early in the course ^[1].

Condition-Specific Interventions

• STEMI: Activate the cardiac catheterization lab immediately (Door-to-balloon time <90 minutes). Do not delay for troponin results if EKG is diagnostic.
• Aortic Dissection: Emergency cardiothoracic surgery consult. Aggressive heart rate and BP control (Beta-blocker first, e.g., Esmolol or Labetalol, to reduce aortic wall stress).
• Pericarditis: High-dose NSAIDs (Ibuprofen 400-800 mg TID) and Colchicine (0.5mg BID). Steroids are reserved for refractory cases.

7. Safety Precautions and Complications

• Hypotension: NTG can cause severe hypotension, especially in RV infarction. Always check for JVD and clear lung fields before administering NTG.
• Bleeding Risk: Anticoagulants and antiplatelets carry significant bleeding risks. Evaluate for contraindications (active ulcer, recent stroke).
• Red Flags (Do Not Miss):
  • Tearing pain + pulse deficit = Aortic Dissection.
  • JVD + Muffled Heart Tones + Hypotension = Cardiac Tamponade (Beck's Triad).
  • Localized pain to a single rib + tenderness = Costochondritis (note: this is a diagnosis of exclusion after ruling out cardiac causes).

8. Exam Tips and High-Yield Points

• Memory Aid (MONA is outdated): The acronym MONA (Morphine, O2, NTG, Aspirin) is no longer the standard. Instead, remember "OAN-BL": Oxygen (prn), Aspirin, Nitroglycerin, Beta-blockers, Limos (Statins).
• Troponin is King: Elevated troponin = myocardial injury until proven otherwise. Do not dismiss an abnormal troponin as "artifactual."
• Wellen's Signs: Deep, symmetric T-wave inversions in V2-V3 indicate critical proximal LAD stenosis. This is a pre-infarction syndrome and requires urgent cardiology consultation ^[3].
• Women Present Differently: Remember that fatigue, dyspnea, and indigestion are common presenting symptoms of ACS in women. Delay in recognition leads to higher mortality ^[4].
• Pericarditis vs. STEMI: Pericarditis has diffuse ST elevation with concave upward morphology AND PR depression. STEMI usually follows a vascular distribution and has convex (tombstone) morphology.

9. References & Sources

1. O'Gara, P. T., Kushner, F. G., Ascheim, D. D., et al. (2013). 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction. Circulation. https://doi.org/10.1161/CIR.0b013e3182742cf6
2. Collet, J. P., Thiele, H., Barbato, E., et al. (2020). 2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. European Heart Journal. https://doi.org/10.1093/eurheartj/ehaa575
3. Tintinalli, J. E., Ma, O. J., Yealy, D. M., et al. (2020). Tintinalli's Emergency Medicine: A Comprehensive Study Guide (9th ed.). McGraw-Hill Education. https://accessmedicine.mhmedical.com/book.aspx
4. Buttaro, T. M., Trybulski, J., Polgar-Bailey, P., & Sandberg-Cook, J. (2021). Primary Care: A Collaborative Practice (6th ed.). Elsevier. https://shop.elsevier.com/books/primary-care/buttaro/978-0-323-55630-9
5. Lewis, S. L., Bucher, L., Heitkemper, M. M., & Harding, M. M. (2023). Medical-Surgical Nursing: Assessment and Management of Clinical Problems (12th ed.). Elsevier. https://www.elsevier.com/books/medical-surgical-nursing/lewis/978-0-323-79433-4