What is the appropriate management for a patient presenting with chest pain of suspected cardiac origin?

Management of Chest Pain of Suspected Cardiac Origin

Immediate Actions (Within 10 Minutes)

All patients presenting with chest pain suspicious for acute coronary syndrome (ACS) must have an ECG performed and interpreted within 10 minutes of arrival, regardless of setting. 1, 2

Initial Assessment and Stabilization

• Place the patient on continuous cardiac monitoring immediately with emergency resuscitation equipment and defibrillator nearby 1, 2
• Obtain intravenous access and draw blood for cardiac troponin (cTn), complete blood count, and basic metabolic panel 1, 2
• Administer aspirin 160-325 mg orally (chewed for faster absorption) unless contraindicated 2
• Provide supplemental oxygen via nasal cannula if oxygen saturation is low or respiratory distress is present 2
• Administer sublingual nitroglycerin (0.4 mg) unless systolic blood pressure <90 mmHg or heart rate <50 or >100 bpm 2
• Give adequate analgesia with morphine sulfate (2-4 mg IV) for persistent pain unrelieved by nitroglycerin 2

Critical Physical Examination Elements

• Perform a focused cardiovascular examination to identify life-threatening causes: aortic dissection (pulse differential, blood pressure differential in upper extremities), pulmonary embolism (tachypnea, hypoxia, unilateral leg swelling), cardiac tamponade (jugular venous distension, muffled heart sounds, hypotension), or esophageal rupture 1
• Assess for signs of heart failure: pulmonary rales, elevated jugular venous pressure, peripheral edema 2
• Evaluate for hemodynamic instability: hypotension, tachycardia, altered mental status 2

ECG-Directed Management Pathway

STEMI (ST-Segment Elevation or New LBBB)

Patients with ST-segment elevation myocardial infarction require immediate reperfusion therapy with a door-to-balloon time goal of <90 minutes or door-to-needle time of <30 minutes. 1, 2

• Activate the cardiac catheterization laboratory immediately for primary percutaneous coronary intervention (PCI) 2
• Continue aspirin and administer heparin (unfractionated or low-molecular-weight) 2
• Administer dual antiplatelet therapy with P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) 2
• Consider beta-blocker administration (metoprolol 5 mg IV every 5 minutes for 3 doses, then 50 mg PO every 6 hours) if no contraindications exist: heart failure, hypotension, bradycardia, or bronchospastic disease 2, 3

Non-ST-Elevation ACS (NSTE-ACS)

For patients without ST-elevation but with suspected ACS, measure cardiac troponin immediately and repeat at 6-12 hours to risk-stratify. 1, 2

• Administer aspirin 75-150 mg daily if not already given 2
• Start anticoagulation with low-molecular-weight heparin or unfractionated heparin 2
• Continue beta-blockers and nitrates for persistent or recurrent chest pain 2
• Use calcium channel blockers only if beta-blockers are contraindicated 2

High-Risk Features Requiring Urgent Intervention (Within 48 Hours)

• Recurrent ischemia (ongoing chest pain or dynamic ECG changes) 2
• Elevated troponin levels 2
• Hemodynamic instability (hypotension, pulmonary edema) 2
• Major arrhythmias (ventricular tachycardia, ventricular fibrillation) 2
• Early post-infarction unstable angina 2
• Diabetes mellitus 2

High-risk patients should undergo coronary angiography within 48 hours. 2

Normal or Non-Diagnostic ECG

Even with a normal initial ECG, patients cannot be discharged if ACS is suspected—serial ECGs and troponin measurements are mandatory. 1, 2

• Repeat ECG if symptoms recur or at regular intervals (every 15-30 minutes during active symptoms) 2
• Obtain second troponin measurement at 6-12 hours after symptom onset 1, 2
• Continue continuous multi-lead ECG monitoring to detect dynamic changes 2

Setting-Specific Protocols

Office/Outpatient Setting

Patients with clinical evidence of ACS or life-threatening chest pain seen in the office must be transported urgently to the emergency department by EMS—do not delay for troponin testing in the office. 1

• If ECG is unavailable in the office, refer the patient to the emergency department immediately 1
• Never perform telephone-only evaluation for patients with possible accelerating angina or rest angina—physical examination, ECG, and cardiac biomarkers are essential 1
• Patients with known coronary artery disease experiencing worsening symptoms should call 9-1-1 directly if discomfort is moderate to severe or sustained 1

Emergency Department Protocol

All patients presenting to the ED with acute chest pain must have cTn measured as soon as possible after presentation. 1

• Use structured chest pain protocols or critical pathways to standardize evaluation—this multidisciplinary approach improves clinical outcomes and cost-effectiveness 1
• Low-risk patients (normal ECG, negative initial troponin, no high-risk features) may undergo observation with serial testing over 6 hours followed by provocative stress testing before discharge 2, 4
• Moderate-risk patients require 6-hour observation with serial ECGs and cardiac biomarkers, followed by functional testing (exercise echocardiography or myocardial perfusion imaging) 4

Critical Pitfalls to Avoid

• Do not use nitroglycerin response as a diagnostic criterion—relief with nitroglycerin does not confirm myocardial ischemia 1
• Do not abruptly discontinue beta-blockers in patients with coronary artery disease—this can precipitate severe angina exacerbation, myocardial infarction, or ventricular arrhythmias 3
• Do not administer beta-blockers alone in pheochromocytoma—always give alpha-blocker first to avoid paradoxical hypertension 3
• Do not dismiss atypical presentations, especially in women, elderly patients, and diabetics who may present with dyspnea, nausea, or fatigue rather than classic chest pain 1
• Do not delay transport for diagnostic testing in the office setting—time to reperfusion is critical for mortality reduction 1

Alternative Diagnoses to Consider

When cardiac ischemia is ruled out, evaluate for:

• Aortic dissection: sudden-onset ripping chest pain radiating to back, pulse differential, blood pressure differential 1, 5
• Pulmonary embolism: dyspnea, tachypnea, hypoxia, unilateral leg swelling (use Wells criteria for risk stratification) 5
• Pericarditis: sharp positional chest pain worse with lying supine, improved with sitting forward, friction rub 1
• Pneumothorax: sudden-onset pleuritic chest pain, dyspnea, decreased breath sounds 5
• Gastroesophageal reflux disease: burning retrosternal pain, acid regurgitation, sour taste 5
• Musculoskeletal pain: localized pain reproducible by palpation 5