Learning Objective
By the end of this session, the medical student should be able to:
- Explain the pathophysiological basis of angina pectoris.
- Differentiate between stable angina and vasospastic (Prinzmetal) angina.
- Describe pharmacological strategies used to:
- Reduce myocardial oxygen demand
- Improve myocardial oxygen supply
- Correlate the mechanism of action of antianginal drugs with their therapeutic use.
Pathophysiological Basis of Angina
Angina pectoris is the principal clinical manifestation of ischemic heart disease. It occurs when myocardial oxygen demand exceeds oxygen supply.
This imbalance results in transient myocardial ischemia, producing the characteristic retrosternal chest pain associated with angina.
Activity
Types of Angina
| Type of Angina | Underlying Cause | Pathophysiology |
|---|---|---|
| Stable (Effort) Angina | Coronary atherosclerotic narrowing | Fixed obstruction limits the coronary blood flow during increased myocardial workload |
| Vasospastic (Prinzmetal) Angina | Reversible coronary artery spasm | Transient reduction in coronary blood flow due to vasoconstriction |
Pharmacological Drug Strategies
The therapeutic approach to angina is based on restoring the balance between:
- Myocardial Oxygen Demand
- Myocardial Oxygen Supply
| Therapeutic Strategy | Mechanism | Drug Class |
|---|---|---|
| ↓ Oxygen Requirement | ↓ Total Peripheral Resistance (Afterload) ↓ Cardiac Output |
Nitrates β-Blockers Calcium Channel Blockers |
| ↑ Oxygen Delivery | Relief of coronary vasospasm | Nitrates Calcium Channel Blockers |
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