# Clinical Cases: Approach to Chest Pain

## Case 1: Acute Coronary Syndrome

### Patient Presentation
A 58-year-old man with a history of hypertension, type 2 diabetes mellitus, and hyperlipidemia presents to the emergency department with severe substernal chest pain that started 2 hours ago while he was mowing his lawn. He describes the pain as a "crushing" sensation radiating to his left arm and jaw, rated 9/10 in intensity. He also reports associated diaphoresis, nausea, and shortness of breath. He took two aspirin at home before calling EMS.

### Vital Signs
- Blood Pressure: 155/95 mmHg
- Heart Rate: 102 bpm
- Respiratory Rate: 22/min
- Oxygen Saturation: 94% on room air
- Temperature: 37.1°C

### Physical Examination
- General: Anxious, diaphoretic, clutching chest
- Cardiovascular: Tachycardic, regular rhythm, S4 gallop, no murmurs
- Pulmonary: Bibasilar crackles
- Extremities: No edema, peripheral pulses intact

### Initial Workup
- **ECG**: ST-segment elevation in leads V1-V4 with reciprocal ST depression in inferior leads
- **Troponin I**: 0.8 ng/mL (normal <0.04 ng/mL)
- **BNP**: 450 pg/mL (normal <100 pg/mL)

### Clinical Image
![Anterior STEMI ECG](image_01.png)
*Figure 1: 12-lead ECG demonstrating ST-segment elevation in anterior leads (V1-V4) consistent with acute anterior wall ST-elevation myocardial infarction (STEMI).*

**Image Source**: Educational illustration for teaching purposes.

### Questions

1. **What is the most likely diagnosis?**
   - A) Unstable angina
   - B) NSTEMI
   - C) Anterior STEMI
   - D) Pericarditis

2. **What is the most appropriate immediate management?**
   - A) Medical management with anticoagulation and stress testing
   - B) Emergent percutaneous coronary intervention (PCI)
   - C) Thrombolytic therapy
   - D) Coronary artery bypass grafting

3. **Which artery is most likely occluded?**
   - A) Right coronary artery
   - B) Left circumflex artery
   - C) Left anterior descending artery
   - D) Posterior descending artery

4. **What is this patient's HEART score, and what does it indicate?**

5. **What adjunctive medications should be administered in the emergency department?**

### Answers

1. **C) Anterior STEMI** - The patient has classic symptoms of ACS with ST-elevation in leads V1-V4 indicating anterior wall involvement, elevated troponin, and reciprocal changes inferiorly.

2. **B) Emergent percutaneous coronary intervention (PCI)** - Primary PCI is the preferred reperfusion strategy for STEMI when door-to-balloon time can be achieved within 90 minutes. This patient is within the optimal window for intervention.

3. **C) Left anterior descending artery** - ST-elevation in V1-V4 indicates anterior wall involvement, which is supplied by the LAD artery. The LAD supplies the anterior wall of the left ventricle and the anterior two-thirds of the interventricular septum.

4. **HEART Score Calculation:**
   - History: Highly suspicious (2 points)
   - ECG: Significant ST-elevation (2 points)
   - Age: 58 years (1 point)
   - Risk factors: HTN, DM, hyperlipidemia (2 points)
   - Troponin: >3x normal (2 points)
   - **Total: 9 points** - High risk, indicating need for emergent intervention

5. **Adjunctive medications:**
   - Aspirin 325 mg (already taken)
   - P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel)
   - Anticoagulation (unfractionated heparin or bivalirudin)
   - High-intensity statin
   - Beta-blocker (if no contraindications)
   - Supplemental oxygen if SpO2 <90%
   - Morphine for pain control (with caution)
   - Nitroglycerin for ongoing ischemic symptoms (if BP allows)

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## Case 2: Aortic Dissection

### Patient Presentation
A 67-year-old man with a history of long-standing poorly controlled hypertension presents with sudden-onset severe chest pain that began 45 minutes ago. He describes the pain as "tearing" in quality, starting in his anterior chest and radiating to his back between his shoulder blades. The pain was maximal at onset. He denies shortness of breath or diaphoresis.

### Vital Signs
- Blood Pressure: Right arm 185/110 mmHg, Left arm 145/85 mmHg
- Heart Rate: 88 bpm
- Respiratory Rate: 18/min
- Oxygen Saturation: 97% on room air

### Physical Examination
- General: In significant distress due to pain
- Cardiovascular: Regular rhythm, new early diastolic murmur at left sternal border
- Pulmonary: Clear to auscultation
- Neurological: No focal deficits
- Extremities: Blood pressure differential >20 mmHg between arms

### Initial Workup
- **ECG**: Normal sinus rhythm, no ST-T changes
- **Troponin I**: <0.04 ng/mL (normal)
- **D-dimer**: 2,450 ng/mL (normal <500 ng/mL)
- **Chest X-ray**: Widened mediastinum

### Questions

1. **What is the most likely diagnosis?**
   - A) Acute coronary syndrome
   - B) Pulmonary embolism
   - C) Aortic dissection
   - D) Pericarditis

2. **What is the most appropriate next diagnostic test?**
   - A) Stress testing
   - B) CT angiography of the chest
   - C) Transthoracic echocardiography
   - D) Coronary angiography

3. **What is the significance of the new diastolic murmur?**

4. **What is the initial blood pressure management goal?**

5. **What classification system is used for aortic dissection, and how would this patient be classified?**

### Answers

1. **C) Aortic dissection** - The classic presentation includes sudden-onset severe tearing/ripping chest pain radiating to the back, maximal at onset, blood pressure differential between arms, widened mediastinum on chest X-ray, and new aortic regurgitation murmur.

2. **B) CT angiography of the chest** - CTA is the imaging modality of choice for suspected aortic dissection, with sensitivity and specificity >95%. It provides detailed anatomic information about the extent of dissection.

3. **Significance of diastolic murmur**: The new early diastolic murmur indicates aortic regurgitation, which occurs when the dissection extends proximally to involve the aortic root and disrupts the aortic valve apparatus. This is a concerning finding that may indicate need for surgical repair.

4. **Blood pressure management goal**:
   - Target systolic BP: 100-120 mmHg
   - Target heart rate: <60 bpm
   - First-line agents: IV beta-blockers (esmolol, labetalol)
   - Add vasodilators (nitroprusside) if needed after beta-blockade
   - Beta-blockers must be given before vasodilators to prevent reflex tachycardia

5. **Classification systems**:
   - **Stanford Classification**:
     - Type A: Involves ascending aorta (requires emergent surgery)
     - Type B: Involves descending aorta only (usually medical management)
   - **DeBakey Classification**:
     - Type I: Originates in ascending, propagates distally
     - Type II: Confined to ascending aorta
     - Type III: Originates in descending aorta

   This patient likely has a **Stanford Type A** dissection given the involvement of the aortic root (evidenced by aortic regurgitation), requiring emergent surgical consultation.

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## Learning Points

1. **Chest pain risk stratification** requires systematic evaluation using history, physical examination, ECG, and cardiac biomarkers.

2. **STEMI management** emphasizes rapid reperfusion with door-to-balloon time <90 minutes for PCI.

3. **Aortic dissection** should be suspected with tearing chest pain, blood pressure differential, and widened mediastinum.

4. **The HEART score** helps risk-stratify patients with chest pain for appropriate disposition.

5. **Life-threatening causes of chest pain** (ACS, aortic dissection, pulmonary embolism, tension pneumothorax, esophageal rupture) must be rapidly identified and treated.