## First-Line Antianginal Therapy in Stable Angina **Key Point:** Beta-blockers are the first-line agents for stable angina in patients with preserved left ventricular function, as they reduce myocardial oxygen demand by decreasing heart rate, contractility, and blood pressure. ### Mechanism of Beta-Blockers in Angina 1. **Reduction of myocardial oxygen demand** — the primary antianginal mechanism 2. **Decreased heart rate** — increases diastolic filling time and coronary perfusion 3. **Reduced contractility** — lowers wall tension and oxygen consumption 4. **Blood pressure reduction** — decreases afterload ### Comparative Efficacy in Stable Angina | Drug Class | Mechanism | First-Line Status | Special Indications | |---|---|---|---| | Beta-blockers | ↓ O₂ demand, ↓ HR, ↓ contractility | **Yes** | All patients without contraindications | | Calcium channel blockers | Vasodilation, ↓ afterload | Second-line | Vasospastic angina, hypertension | | Long-acting nitrates | Vasodilation, ↓ preload | Second-line (add-on) | Symptom relief, combination therapy | | Ranolazine | Metabolic modulation | Third-line | Refractory angina | **High-Yield:** Beta-blockers are preferred in stable angina because they address the fundamental pathophysiology—myocardial oxygen supply-demand mismatch—rather than merely dilating vessels. ### Clinical Advantages of Beta-Blockers - Reduce anginal frequency and severity - Increase exercise tolerance - Reduce mortality post-MI (cardioprotective) - Cost-effective and well-tolerated - Evidence-based (multiple RCTs support their use) **Clinical Pearl:** In patients with concurrent hypertension, heart failure, or prior MI, beta-blockers offer additional cardioprotective benefits beyond antianginal effect, making them the clear first choice. **Warning:** Do not confuse with vasospastic (Prinzmetal's) angina, where calcium channel blockers or nitrates are preferred over beta-blockers.
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