Managing Acute Chest Pain

Managing Acute Chest Pain

Guides the evaluation and management of acute chest pain following ACS pathways with troponin timing, risk stratification, and evidence-based disposition criteria.

Why This Skill Exists

Chest pain accounts for approximately 6-8 million ED visits annually in the United States, making it the second most common reason for emergency evaluation. Acute coronary syndrome (ACS) — encompassing STEMI, NSTEMI, and unstable angina — must be rapidly identified because delays in reperfusion directly increase mortality. The ACC/AHA mandate a door-to-ECG time of ≤10 minutes and door-to-balloon time of ≤90 minutes for STEMI. Simultaneously, approximately 85% of chest pain patients do not have ACS, and overtesting generates billions in unnecessary healthcare spending annually.

High-sensitivity troponin (hs-cTn) assays have transformed chest pain evaluation by enabling accelerated diagnostic protocols (0/1-hour or 0/3-hour algorithms) that can safely discharge low-risk patients within hours. Failure to follow validated protocols leads to both missed MI (2% of ED-discharged MIs result in litigation, with average settlements >$500,000) and excessive observation admissions. This skill provides a systematic framework for chest pain evaluation, troponin interpretation, and disposition decision-making.

Checkpoint A: Pre-Draft Intake (Mandatory)

1. What is the character, onset, and duration of chest pain? (Default: document using OLDCARTS)
2. What is the 12-lead ECG result and time of acquisition? (Default: obtain within 10 minutes of arrival)
3. What is the initial troponin value, assay type, and draw time? (Default: document conventional vs. hs-cTn and time relative to symptom onset)
4. What are the patient's cardiac risk factors? (Default: HTN, DM, hyperlipidemia, smoking, family hx, obesity, prior CAD)
5. What is the HEART score? (Default: calculate and document all 5 components)
6. Is there a prior cardiac history (prior MI, stent, CABG, stress test, cath)? (Default: query and document dates)
7. Is the patient on anticoagulants or antiplatelets? (Default: document all antiplatelet and anticoagulant medications)
8. Are there signs of hemodynamic instability? (Default: assess HR, BP, SpO2, signs of shock)

Documents to Request

• 12-lead ECG (obtain immediately; serial ECGs if ongoing symptoms)
• Prior ECGs for comparison
• Initial and serial troponin values with draw times
• Chest X-ray (portable AP)
• Prior cardiac catheterization reports
• Prior stress test or coronary CTA results
• Complete medication list
• Problem list with cardiac risk factors documented

Step 1: Initial Assessment and STEMI Screening

Immediate Actions (within 10 minutes of arrival)

1. 12-lead ECG acquired and interpreted
2. Continuous cardiac monitoring initiated
3. IV access established
4. Initial troponin drawn (document exact time relative to pain onset)
5. Aspirin 324 mg chewed (if no contraindication)

STEMI Identification

STEMI criteria (≥2 contiguous leads):

• ST elevation ≥1 mm limb leads
• ST elevation ≥2 mm V2-V3 (men ≥40), ≥2.5 mm (men <40), ≥1.5 mm (women)

STEMI equivalents requiring cath lab activation:

• New LBBB with positive Sgarbossa or Smith-modified Sgarbossa
• de Winter T-wave pattern (upsloping ST depression + hyperacute T waves in V1-V6)
• Posterior MI (ST depression V1-V3 with tall R; confirm with V7-V9)
• Diffuse ST depression with ST elevation in aVR (left main/severe 3-vessel)

If STEMI or equivalent identified:

• Activate cath lab immediately (target door-to-balloon ≤90 minutes)
• Administer: aspirin 324 mg, heparin bolus per protocol, P2Y12 inhibitor per cardiology preference
• Avoid: nitroglycerin if RV involvement (check V4R), SBP <90, PDE5 inhibitor within 24-48 hours

Step 2: Non-STEMI Risk Stratification

For patients without STEMI on initial ECG, proceed with risk stratification:

HEART Score Calculation

Risk-Based Pathway Selection

Step 3: Troponin Interpretation and Serial Testing

High-Sensitivity Troponin (hs-cTn) Protocols

0/1-Hour Algorithm (ESC 2020):

0/3-Hour Algorithm (alternative):

• 0h and 3h troponin both below 99th percentile with delta <50% → rule out
• Either elevated or significant rise → rule in

Conventional Troponin Protocol

• Initial troponin at presentation
• Repeat at 3 hours and 6 hours from symptom onset
• Both negative with low pre-test probability → discharge
• Elevation above 99th percentile → admission

Common Troponin Pitfalls

• Early presenters (<2h from onset): Troponin may not yet be detectable — serial testing mandatory
• Troponin elevation ≠ MI: Causes of non-ACS troponin elevation include PE, heart failure, myocarditis, sepsis, renal failure, tachyarrhythmia, Takotsubo
• Type 1 vs. Type 2 MI: Type 1 = plaque rupture; Type 2 = supply/demand mismatch (tachycardia, anemia, hypotension) — treatment differs fundamentally

Step 4: Non-ACS Causes of Chest Pain to Rule Out

Before attributing chest pain to a non-cardiac cause, actively exclude:

Step 5: Disposition and Discharge Planning

Safe Discharge Criteria (all must be met)

• HEART score 0-3
• Serial troponins negative (both below 99th percentile with no significant delta)
• Non-ischemic ECG (no ST changes, no new T-wave inversions)
• Hemodynamically stable
• Symptoms resolved or clearly non-cardiac etiology identified
• Reliable follow-up within 72 hours available

Discharge Instructions Must Include

• Specific diagnosis or working diagnosis documented
• Medication changes (aspirin, statin, nitroglycerin if prescribed)
• Return precautions: "Return immediately if chest pain recurs, becomes more severe, is accompanied by shortness of breath, sweating, or arm/jaw pain"
• Follow-up appointment with PCP or cardiologist within 72 hours
• Activity restrictions if applicable
• Smoking cessation counseling if smoker (Joint Commission core measure)

Observation / Admission Criteria

• HEART score 4-6: observation with serial troponins + functional testing
• HEART score ≥7: inpatient admission with cardiology consult
• Any positive troponin: admission (even if HEART score is low)
• Dynamic ECG changes: admission regardless of troponin
• Hemodynamic instability: ICU admission

Checkpoint B: Post-Draft Alignment (Mandatory)

1. Was a 12-lead ECG obtained within 10 minutes and interpreted for STEMI criteria and equivalents?
2. Was the HEART score calculated with all 5 component values documented?
3. Were troponin results interpreted with appropriate timing relative to symptom onset?
4. Were non-ACS dangerous diagnoses (PE, dissection, pneumothorax, tamponade) actively considered?
5. Does the disposition (discharge, observation, admission) align with the risk stratification results?

Quality Audit

• ECG obtained within 10 minutes of arrival and documented
• HEART score calculated with all component values listed
• Initial troponin draw time documented relative to symptom onset
• Serial troponin protocol followed with appropriate timing intervals
• STEMI criteria evaluated including equivalents (Sgarbossa, de Winter, posterior)
• Non-ACS life threats actively considered (PE, dissection, pneumothorax, tamponade)
• Aspirin administered (or contraindication documented)
• Troponin assay type specified (conventional vs. high-sensitivity)
• Type 1 vs. Type 2 MI differentiated if troponin elevated
• Disposition aligns with HEART score risk category
• Discharge instructions include specific return precautions for ACS symptoms
• Follow-up arranged within 72 hours for discharged patients
• Shared decision-making documented for borderline cases
• Smoking cessation counseling documented if applicable (Joint Commission measure)

Guidelines

1. Never discharge a chest pain patient without at least one troponin result — if troponin is drawn <2 hours from symptom onset, a second troponin is mandatory before safe discharge.
2. A normal ECG does not rule out ACS — sensitivity of a single ECG is only 45-60% for acute MI; serial ECGs are indicated for ongoing symptoms.
3. Apply the HEART score as a structured framework, not a rigid cutoff — a patient with a HEART score of 3 who "looks sick" clinically warrants further evaluation regardless of the number.
4. Document the troponin assay type (conventional vs. high-sensitivity) — the interpretation thresholds and timing protocols differ fundamentally between assay types.
5. Always check right-sided leads (V4R) in inferior STEMI — RV infarction changes management (volume instead of nitroglycerin, avoid preload reducers).
6. Aortic dissection is the chest pain diagnosis most commonly missed in the ED — maintain high suspicion for tearing/ripping pain radiating to the back, especially with hypertension or connective tissue disease history.
7. Troponin elevation in the context of tachycardia, sepsis, or renal failure is likely Type 2 MI or non-ischemic elevation — treatment is directed at the underlying cause, not antiplatelet/anticoagulant therapy.
8. The HEART Pathway (HEART score + serial troponins + ECG) has been validated to safely identify <1% MACE risk patients for early discharge — this is the evidence base for accelerated diagnostic protocols.