A 58-year-old man with a 3-year history of stable angina presents to the emergency department with chest pain at rest lasting 20 minutes. He is on aspirin 75 mg daily and atenolol 50 mg once daily. On examination, BP is 145/92 mmHg, HR 88/min, and an ECG shows 2 mm ST depression in leads II, III, aVF with T-wave inversion. Troponin I is negative. What is the most appropriate immediate next step in management?

Explanation

## Clinical Scenario Analysis This patient presents with **unstable angina** (rest angina with ECG changes and negative troponin), not stable angina. The transition from stable to unstable angina represents acute coronary syndrome (ACS) and requires escalation of antianginal therapy. ## Immediate Management Strategy **Key Point:** Unstable angina requires dual antianginal therapy plus anticoagulation, even with negative troponin. ### Step-by-step approach: 1. **Sublingual nitroglycerin** — immediate relief of acute ischemia and vasodilation 2. **IV unfractionated heparin (UFH)** — prevents thrombus propagation in unstable angina; UFH preferred over LMWH in ACS because of potential for urgent revascularization 3. **Calcium channel blocker (e.g., diltiazem or verapamil)** — adds antianginal effect and rate control; particularly useful if beta-blocker alone is insufficient **High-Yield:** Unstable angina with ECG changes warrants: - Antiplatelet therapy (already on aspirin) - Anticoagulation (UFH or LMWH) - Dual antianginal therapy (beta-blocker + nitrate ± CCB) - Risk stratification and possible coronary angiography ## Why This Differs from Stable Angina | Feature | Stable Angina | Unstable Angina | |---------|---------------|------------------| | Trigger | Predictable exertion | Rest or minimal exertion | | ECG at rest | Normal | ST depression / T-wave changes | | Troponin | Negative | Negative (but risk of elevation) | | Management | Monotherapy often sufficient | Dual/triple antianginal + anticoagulation | | Urgency | Outpatient optimization | Acute admission, possible cath | **Clinical Pearl:** Negative troponin does NOT exclude ACS; it simply means myocardial necrosis has not yet occurred. The ECG changes and clinical presentation (rest pain in a previously stable patient) define the diagnosis. **Mnemonic — ACS Management (MONA):** Morphine, Oxygen, Nitroglycerin, Aspirin + Anticoagulation (UFH/LMWH) + Additional antianginal (CCB/second nitrate). [cite:Harrison 21e Ch 297]