What is the appropriate diagnostic approach for a patient presenting with chest pain, considering their age, medical history, and risk factors for cardiovascular disease?

Diagnostic Approach for Chest Pain

Obtain a 12-lead ECG within 10 minutes of presentation and measure high-sensitivity cardiac troponin immediately—these two tests form the foundation of chest pain evaluation and must be performed before any other diagnostic considerations. 1, 2

Immediate Assessment (First 10 Minutes)

ECG Acquisition and Interpretation

• Acquire and interpret a 12-lead ECG within 10 minutes to identify ST-segment elevation, ST-segment depression, new Q waves, T-wave inversions, or new left bundle branch block 1, 2, 3
• Compare with previous ECG if available, as this is particularly valuable in patients with pre-existing left ventricular hypertrophy or bundle branch blocks 2
• If initial ECG is nondiagnostic but clinical suspicion remains high, repeat ECG every 15-30 minutes during the first hour 1, 4
• Consider supplemental leads V7-V9 to detect posterior MI in patients with intermediate-to-high clinical suspicion 4
• Initiate continuous multi-lead ECG monitoring for arrhythmias and dynamic ST-segment changes 2

Cardiac Biomarker Strategy

• Measure high-sensitivity cardiac troponin (hs-cTn) immediately upon presentation as the preferred marker of myocardial damage 2, 4, 3
• Repeat troponin at 3-6 hours after symptom onset using contemporary or high-sensitivity assays 1, 4
• If initial troponin is normal but symptoms persist or ECG changes develop, obtain additional troponin levels beyond 6 hours 4
• Do not use total CK alone—it is neither sensitive nor specific enough to diagnose or exclude acute myocardial infarction 3
• A rising and/or falling pattern of troponin values is diagnostic for acute myocardial injury 4

Critical History Elements

Pain Characteristics That Suggest Acute Coronary Syndrome

• Retrosternal chest discomfort described as pressure, heaviness, tightness, constriction, or squeezing that builds gradually over minutes 1, 2, 3
• Radiation to left arm, jaw, neck, or both arms (radiation to both arms: specificity 96%, LR 2.6) 1, 5
• Pain triggered by physical exercise or emotional stress 1
• Pain occurring at rest or with minimal exertion, especially if associated with dyspnea, diaphoresis, nausea, or lightheadedness 1, 2

Pain Characteristics That Suggest Non-Ischemic Causes

• Sharp chest pain that increases with inspiration and lying supine suggests pericarditis, not ischemic heart disease 1, 2
• Sudden onset of ripping or tearing chest pain with radiation to upper or lower back suggests acute aortic dissection 1, 4, 3
• Fleeting chest pain of few seconds' duration is unlikely related to ischemic heart disease 1
• Pain localized to a very limited area or radiating below the umbilicus is unlikely myocardial ischemia 1
• Positional chest pain is usually nonischemic (musculoskeletal) 1

High-Risk Features Requiring Immediate Action

• Prior abnormal stress test (specificity 96%, LR 3.1) 5
• Peripheral arterial disease (specificity 97%, LR 2.7) 5
• Known coronary artery disease or prior myocardial infarction 2, 4
• Age >70 years, diabetes mellitus, or multiple cardiovascular risk factors 2, 4

Physical Examination Priorities

Emergency ACS Findings

• Diaphoresis, tachypnea, tachycardia, hypotension 1
• Crackles, S3 gallop, new mitral regurgitation murmur 1
• Note: Examination may be completely normal in uncomplicated cases 1

Aortic Dissection Findings

• Pulse differential between extremities (present in 30% of patients) 1
• Blood pressure differential >20 mmHg between arms 4
• New aortic regurgitation murmur 1, 4
• Features of connective tissue disorders (Marfan syndrome) 1

Pulmonary Embolism Findings

• Tachycardia and dyspnea present in >90% of patients 1, 4
• Pain with inspiration 1

Risk Stratification Using Validated Scores

HEART Score (Preferred for Emergency Department Use)

• High-risk range (7-10): LR 13 for diagnosing ACS 5
• Low-risk range (0-3): LR 0.20 for excluding ACS 5
• Components: History, ECG, Age, Risk factors, Troponin 5

TIMI Score

• High-risk range (5-7): LR 6.8 for diagnosing ACS 5
• Low-risk range (0-1): LR 0.31 for excluding ACS 5

Imaging Studies Based on Risk Stratification

For Intermediate-High Risk Patients with Stable Chest Pain

• CCTA (coronary CT angiography) is reasonable as first-line anatomic testing, particularly in patients <65 years of age 1
• Stress testing (stress CMR, PET, SPECT MPI, or echocardiography) is reasonable, particularly in patients ≥65 years of age with higher likelihood of ischemia 1
• Exercise ECG is appropriate for patients without baseline ECG abnormalities and who can exercise 1

For Patients with Obstructive CAD on CCTA

• FFR-CT (fractional flow reserve with CT) for 40-90% stenosis is useful for diagnosis of vessel-specific ischemia and to guide revascularization decisions 1
• If FFR-CT <0.8 or moderate-severe ischemia on stress testing, proceed to invasive coronary angiography 1

For Patients After Inconclusive Initial Testing

• After inconclusive or abnormal exercise ECG or stress imaging, CCTA is reasonable 1
• After inconclusive CCTA, stress imaging is reasonable 1

Chest Radiography

• Obtain chest radiograph to evaluate for pulmonary venous congestion, cardiomegaly, pneumonia, pneumothorax, pleural effusion, and widened mediastinum (aortic dissection) 2, 4
• Do not delay urgent interventions if ACS is suspected 4

Special Population Considerations

Women

• Women frequently present with atypical symptoms: nausea, fatigue, dyspnea, jaw pain, and epigastric discomfort rather than classic chest pain 2, 4, 3
• Arm pain, jaw pain, and bilateral hand numbness may represent anginal equivalent symptoms 3
• Women are at risk for underdiagnosis and require specific inquiry about accompanying symptoms 4, 3

Older Adults (≥75 Years)

• May present with isolated dyspnea, syncope, acute delirium, or unexplained falls without classic chest pain 2, 4, 3
• Maintain high suspicion for ACS even with minimal or atypical symptoms 2
• Older adults with diabetes, renal insufficiency, or dementia require immediate attention 4

Critical Pitfalls to Avoid

Common Diagnostic Errors

• Do not rely on nitroglycerin response as diagnostic for myocardial ischemia—esophageal spasm and other conditions respond similarly 1, 4, 3
• Do not assume young age excludes ACS—it can occur in adolescents without traditional risk factors 3
• Do not dismiss sharp, pleuritic pain as automatically non-cardiac—pericarditis and atypical ACS presentations can occur 3
• A normal initial ECG does not exclude ACS—up to 6% of patients with evolving ACS have normal initial ECG, particularly with left circumflex or right coronary artery occlusions 4
• Do not delay transfer for office-based troponin testing when ACS is suspected—delayed transfer is harmful 4, 3

Electrocardiographic Pitfalls

• Left ventricular hypertrophy, bundle branch blocks, and ventricular pacing may mask ischemic changes 4
• ST-segment depression has specificity of 95% and LR of 5.3 for ACS 5
• Any evidence of ischemia on ECG has specificity of 91% and LR of 3.6 for ACS 5

Disposition Algorithm

Immediate Invasive Management

• STEMI (ST-elevation MI): Door-to-balloon time <90 minutes for primary PCI (preferred) or door-to-needle time <30 minutes for fibrinolytic therapy 4, 3
• High-risk CAD: Left main stenosis ≥50% or anatomically significant 3-vessel disease (≥70% stenosis) requires invasive coronary angiography 1
• Obstructive CAD with moderate-severe ischemia despite guideline-directed medical therapy requires ICA for therapeutic decision-making 1

Admission Criteria

• Elevated troponin above 99th percentile without ST-elevation requires coronary care unit admission with continuous monitoring 3
• Recurrent ischemia, hemodynamic instability, or elevated troponin during observation period are high-risk features requiring aggressive management 2, 4

Safe Discharge Criteria

• Low-risk by HEART score (0-3) or TIMI score (0-1) with normal ECG and troponin 5
• No high-risk features during 8-12 hour observation period 2
• Normal stress testing or CCTA showing no CAD 1