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Chest Discomfort¶

Chapter 15 | Part 2: Cardinal Manifestations and Presentation of Diseases · Part 2 – Cardinal Manifestations & Presentation · Chapter 15

Key Clinical Points¶

Myocardial ischemia results from an imbalance between myocardial oxygen demand (heart rate, wall stress, contractility) and supply (coronary blood flow × oxygen content).
Acute coronary syndrome (ACS) includes unstable angina, NSTEMI, and STEMI.
Stable angina is typically predictable, triggered by exertion/stress, and relieved by rest or nitroglycerin within minutes.
Unstable angina presents with a lower threshold for symptoms or occurs at rest.
Levine's sign: Patient clutching the chest with a clenched fist against the sternum.
Tearing or ripping pain is highly suggestive of acute aortic dissection.
Radiation to both arms/shoulders has a high association with myocardial infarction (MI).
Chest wall tenderness does not exclude underlying myocardial ischemia.
High-sensitivity cardiac troponin assays are the preferred biomarker for MI diagnosis.
The risk of major cardiovascular events in low-risk acute chest pain patients is approximately 2.5% within 30 days.

DEFINITION & CLASSIFICATION¶

• Definition (Harrison's 22e): Myocardial ischemia causing chest discomfort, termed angina pectoris, is a primary clinical concern in patients presenting with chest symptoms. • Pathophysiology of Ischemia: ◦ Imbalance between oxygen demand and supply. ◦ Demand factors: Increased heart rate, ventricular wall stress, and myocardial contractility. ◦ Supply factors: Coronary blood flow and coronary arterial oxygen content. ◦ Critical Threshold: Irreversible cellular injury (MI) occurs if ischemia is severe/prolonged for as little as 20 min. • Acute Coronary Syndrome (ACS): ◦ Includes: Unstable angina, NSTEMI, and STEMI. ◦ Typically precipitated by acute coronary atherothrombosis. • Myocardial Injury Classifications: ◦ Stable Angina: Ischemic episodes triggered by exertion/stress; relieved by rest or nitroglycerin within minutes. ◦ Unstable Angina: No detectable acute myocardial injury; occurs with lower intensity of activity or at rest. ◦ NSTEMI: Evidence of acute myocardial injury without ST-segment elevation. ◦ STEMI: Evidence of acute myocardial injury with ST-segment elevation. ◦ Type 1 MI: Resulting from acute coronary atherothrombosis. ◦ Type 2 MI: Resulting from other imbalances of myocardial oxygen supply and demand.

EPIDEMIOLOGY¶

• Presentation Frequency: One of the three most common reasons for ED visits in the US (6–7 million annually). • Hospitalization Rate: Over 60% of patients with chest discomfort are hospitalized. • ACS Prevalence: Less than 15% (range 5-20%) of patients presenting with acute chest pain are diagnosed with ACS. • Missed Diagnosis: Historically, 2–6% of patients with nonischemic symptoms were later found to have missed MI. • Common Diagnoses: Gastrointestinal causes are most common (42%); Ischemic heart disease (31%); Chest wall syndrome (28%). • Risk Assessment: The estimated rate of major cardiovascular events within 30 days in low-risk acute chest pain patients is 2.5%.

ETIOLOGY & PATHOPHYSIOLOGY¶

• Ischemic Heart Disease: Driven by oxygen supply/demand imbalance. • Acute Aortic Syndromes: Includes penetrating ulcer and intramural hematoma; characterized by rupture of the media of the aortic wall. • Pulmonary Embolism (PE): Sudden onset dyspnea/chest discomfort; may be pleuritic due to pulmonary infarction or RV stress. • Pericarditis: Inflammation of pericardium; pain often arises from associated pleural inflammation. • Non-ischemic Myocardial Injury: Examples include myocarditis.

CLINICAL FEATURES¶

• General Characteristics of Angina: ◦ Quality: Aching, heavy, squeezing, crushing, or constricting. ◦ Location: Retrosternal; common radiation to ulnar surface of left arm, neck, jaw, or shoulders. • Temporal Patterns: ◦ Stable Angina: Predictable onset; relieved by rest/nitroglycerin within minutes. ◦ Unstable Angina: Progressively lower intensity of activity required for symptoms; occurs at rest. ◦ Myocardial Infarction (MI): Severe, prolonged (≥30 min), not relieved by rest. • High-Specificity Indicators: ◦ Tearing/Ripping: Suggests aortic dissection. ◦ Sudden onset/Pleuritic: Suggests PE or pneumothorax. ◦ Brief/Fleeting (<few seconds): Rarely ischemic. ◦ Constant for hours/days: Unlikely to be myocardial ischemia.

Typical Clinical Features of Major Causes (Table 15-1)¶

• Cardiac Conditions: ◦ Myocardial Ischemia: Pressure/burning; Retrosternal; S3 or rales if severe. ◦ Pericarditis: Pleuritic, sharp; relieved by sitting up and leaning forward; pericardial friction rub. ◦ Acute Aortic Syndrome: Sudden, unrelenting, tearing/ripping; radiating to back. ◦ Pulmonary Embolism: Sudden, pleuritic; may be heavy in massive cases. • Pulmonary Conditions: ◦ Pneumonia/Pleuritis: Pleuritic; unilateral; fever/rales. ◦ Spontaneous Pneumothorax: Sudden, pleuritic; decreased breath sounds. • Noncardiopulmonary Conditions: ◦ Esophageal Reflux: Burning; 10–60 min; worse when recumbent. ◦ Esophageal Spasm: Pressure/burning; 2–30 min; can mimic angina. ◦ Peptic Ulcer: Burning; 60–90 min after meals. ◦ Gallbladder Disease: Aching/colicky; postprandial; RUQ or epigastric. ◦ Costochondritis: Aching; sternal; reproducible by palpation. ◦ Herpes Zoster: Sharp/burning; dermatomal distribution; vesicular rash.

DIFFERENTIAL DIAGNOSIS¶

• Clinical Assessment Strategy: Focus on quality, location, radiation, and pattern (onset/duration). • High-Risk Conditions: ACS, aortic dissection, pulmonary embolism, tension pneumothorax, pericarditis with tamponade. • Common Mimics: Gastrointestinal disorders (most common), esophageal disorders (mimic angina), musculoskeletal issues.

Diagnostic Assessment Priorities (Table 15-2)¶

• Step 1: Life-Threatening? (Unstable ischemia, Aortic dissection, Pneumothorax, Pulmonary embolism). ◦ If YES → Urgent evaluation/management. ◦ If NO → Proceed to Step 2. • Step 2: Chronic with Serious Complications? (Stable angina, Aortic stenosis, Pulmonary hypertension). ◦ If YES → Manage chronic condition. ◦ If NO → Proceed to Step 3. • Step 3: Acute requiring specific treatment? (Pericarditis, Pneumonia/pleuritis, Herpes zoster). ◦ If YES → Specific treatment. ◦ If NO → Proceed to Step 4. • Step 4: Other treatable conditions? (Esophageal reflux/spasm, Peptic ulcer, Gallbladder disease, Musculoskeletal, Anxiety).

DIAGNOSTIC APPROACH¶

Electrocardiography (ECG): ◦ Timing: Obtain within 10 min of presentation. ◦ Purpose: Identify ST-segment elevation (STEMI) for immediate intervention; detect ischemia via ST-depression/T-wave inversion (≥0.2 mV). ◦ Serial ECGs: Perform every 30–60 min in early ED evaluation. ◦ Right-sided leads: Consider if standard 12-lead is non-diagnostic.
Laboratory Testing: ◦ Cardiac Troponin: Preferred biomarker; use high-sensitivity assays. ◦ Timing: Measure at presentation and repeat at 1–3 h (high-sensitivity) or 3–6 h (conventional). ◦ Rule-out: Use serial troponin to distinguish acute ischemia from chronic injury (e.g., renal failure). ◦ D-dimer: Used to exclude pulmonary embolism. ◦ BNP: Useful for heart failure diagnosis.
Imaging: ◦ Chest Radiograph: Routine; identifies pneumonia, pneumothorax, or widened mediastinum (aortic dissection).
Risk Scoring Systems: • GRACE Score (Table 15-3): ◦ Factors: Age, Known CAD/risk factors, Sex, Symptoms (Radiation, Diaphoresis, Pain with inspiration, Palpation). ◦ Threshold: Low risk = 0–15; Not low risk ≥16. • HEART Score (Table 15-4): ◦ Factors: History (3 levels), ECG (3 levels), Age (3 levels), Risk factors (3 levels). ◦ Threshold: Low risk = 0–3; Not low risk ≥4.

Diagnostic Criteria for AMI Likelihood¶

• Increased Likelihood of AMI: ◦ Radiation to right arm or shoulder. ◦ Radiation to both arms or shoulders. ◦ Associated with exertion. ◦ Radiation to left arm. ◦ Associated with diaphoresis. ◦ Associated with nausea or vomiting. ◦ Worse than previous angina/similar to previous MI. ◦ Described as pressure. • Decreased Likelihood of AMI: ◦ Inframammary location. ◦ Reproducible with palpation. ◦ Described as sharp. ◦ Described as positional. ◦ Described as pleuritic.

MANAGEMENT & TREATMENT¶

Nitroglycerin Administration: • Use to assess for ischemia; relief within minutes suggests ischemia (but not specific). • Note: Esophageal spasm also relieved by nitroglycerin. • Timing Rule: Delay of >10 min before relief → indicates non-ischemic cause OR severe ischemia (e.g., acute MI).
Positioning and Activity: • Patients with myocardial ischemia typically prefer rest/sitting. • Note: 'Warm-up angina' may show relief with continued exertion.
Differential Management Clues: • Movement of neck/arms → suggests musculoskeletal etiology. • Relief by sitting up and leaning forward → suggests pericarditis. • Exacerbation by eating → suggests gastrointestinal (peptic ulcer, gallbladder).
Physical Examination Findings: • General: Anxiety, pallor, cyanosis, diaphoresis; Levine's sign. • Hemodynamics: Tachycardia/hypotension indicate severe consequences; sinus tachycardia may suggest submassive PE. • Pulmonary: Rales or pulmonary edema indicate high risk (heart failure/severe ischemia). • Cardiac: S3/S4 sounds, murmurs of mitral regurgitation (STEMI complication), aortic insufficiency (aortic dissection), pericardial friction rub (pericarditis). • Extremities: Pulse deficits may reflect underlying atherosclerosis.

KEY PEARLS & HIGH-YIELD POINTS¶

• Troponin Dynamics: Dynamic change (rise/fall) = Ischemia; Stable elevation = Chronic injury or non-ischemic acute injury. • Nitroglycerin Timing: <10 min relief → likely ischemia; >10 min → unlikely to be simple ischemia. • Rule of Exclusion: Troponin is not required for patients without suspicion of ACS unless used for risk stratification (e.g., PE). • High-Sensitivity Advantage: Higher negative predictive value in rapid rule-out protocols (1–2 hours).

FLOWCHARTS¶

Decision-aids for evaluation of acute chest pain¶

This flowchart outlines two scoring systems used with serial troponin to identify 'Low Risk' patients.

Pathway A (Risk Factor Scoring): 1. Assess Age: <45 years (0 points); 46–50 y (4 points); 51–55 y (2 points); 56–60 y (0 points); 61–65 y (1 point); 66–70 y (2 points); 71–75 y (3 points); 76–80 y (4 points); 81–85 y (5 points); 86+ y (6 points). 2. Assess Risk Factors: ≥3 risk factors (2 points); 1–2 risk factors (1 point); None (0 points). 3. Calculate Total Score. 4. Decision Node: Is total score 0–3? - YES → Proceed to Troponin check. - NO - NO (≥4) →$ Not low risk. 5. Troponin Check: Is troponin < limit of quantification (LoQ)? - YES → Classified as "Low Risk" (51.8% capture rate). - NO → Not low risk.

Pathway B (Symptom Scoring): 1. Assess Symptoms: - Radiation to arm, shoulder, neck, or jaw: 5 points. - Diaphoresis: 3 points. - Pain with inspiration: -4 points. - Reproduced by palpation: -6 points. 2. Calculate Total Score. 3. Decision Node: Is total score 0–15? - YES → Proceed to Troponin check. - NO (≥16) → Not low risk. 4. Troponin Check: Is troponin < limit of quantification (LoQ)? - YES → Classified as "Low Risk" (60.6% capture rate). - NO → Not low risk.

Clinical Outcome: Both methods provide high Negative Predictive Value (NPV) for MI, cardiogenic shock, cardiac arrest, CABG, and PCI over 80 days (Left: 99.55%; Right: 99.49%).

Reference Tables¶

TABLE 15-1 Typical Clinical Features of Major Causes of Acute Chest Discomfort SYSTEM Cardiopulmonary Cardiac¶

Harrison's 22e, p.103

SYSTEM	CONDITION	ONSET/DURATION	QUALITY	LOCATION	ASSOCIATED FEATURES
Cardiopulmonary
Cardiac	Myocardial ischemia	Stable angina: Precipitated by exertion, cold, or stress; 2–10 min Unstable angina: Increasing pattern or at rest Myocardial infarction: Usually >30 min	Pressure, tightness, squeezing, heaviness, burning	Retrosternal; often radiation to neck, jaw, shoulders, or arms; sometimes epigastric	S gallop or mitral regurgitation 4 murmur (rare) during pain; S 3 or rales if severe ischemia or complication of myocardial infarction
	Pericarditis	Variable; hours to days; may be episodic	Pleuritic, sharp	Retrosternal or toward cardiac apex; may radiate to left shoulder	May be relieved by sitting up and leaning forward; pericardial friction rub
	Acute aortic syndrome Pulmonary embolism Pulmonary hypertension	Sudden onset of unrelenting pain Sudden onset Variable; often exertional	Tearing or ripping; knifelike Pleuritic; may manifest as heaviness with massive pulmonary embolism Pressure	Anterior chest, often radiating to back, between shoulder blades Often lateral, on the side of the embolism Substernal
Pulmonary	Pneumonia or pleuritis	Variable	Pleuritic	Unilateral, often localized	Dyspnea, cough, fever, rales, occasional rub
	Spontaneous pneumothorax	Sudden onset	Pleuritic	Lateral to side of pneumothorax	Dyspnea, decreased breath sounds on side of pneumothorax
Noncardiopulmonary
	Esophageal reflux Esophageal spasm Esophageal injury Peptic ulcer Gallbladder disease, including cholecystitis and biliary colic Pancreatitis	10–60 min 2–30 min Prolonged Prolonged; 60–90 min after meals Prolonged; steady, usually hours Prolonged	Burning Pressure, tightness, burning, intense squeezing Intense squeezing Burning Aching or colicky Typically aching	Substernal, epigastric Retrosternal Retrosternal Epigastric (most common), substernal Epigastric, right upper quadrant; sometimes to the back, scapula, and lower chest Epigastric, radiates to the back
Neuromuscular	Costochondritis	Variable	Aching	Sternal	Sometimes swollen, tender, warm over joint; may be reproduced by localized pressure on examination
	Cervical disk disease	Variable; may be sudden	Aching; may include numbness	Arms and shoulders	May be exacerbated by movement of neck
	Trauma or strain	Usually constant	Aching	Localized to area of strain	Reproduced by movement or palpation
	Herpes zoster	Usually prolonged	Sharp or burning	Dermatomal distribution	Vesicular rash in area of discomfort
	Emotional and psychiatric conditions	Variable; may be fleeting or prolonged	Variable; often manifests as tightness and dyspnea with feeling of panic or doom	Variable; may be retrosternal

TABLE 15-2 Considerations in the Assessment of the Patient with Chest Discomfort 1. Could the chest discomfort be due…¶

Harrison's 22e, p.105

1. Could the chest discomfort be due to an acute, potentially life-threatening condition that warrants urgent evaluation and management?
Unstable ischemic heart disease	Aortic dissection	Pneumothorax	Pulmonary embolism
2. If not, could the discomfort be due to a chronic condition likely to lead to serious complications?
Stable angina	Aortic stenosis	Pulmonary hypertension
3. If not, could the discomfort be due to an acute condition that warrants specific treatment?
Pericarditis	Pneumonia/pleuritis	Herpes zoster
4. If not, could the discomfort be due to another treatable chronic condition?
Esophageal reflux		Cervical disk disease
Esophageal spasm		Arthritis of the shoulder or spine
Peptic ulcer disease		Costochondritis
Gallbladder disease		Other musculoskeletal disorders
Other gastrointestinal conditions		Anxiety state