cardio:angina:start
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Anti-Anginal Therapy
Angina is a mismatch between myocardial oxygen supply and demand.
Therapy targets either:
- ↓ Myocardial oxygen demand
- ↑ Myocardial oxygen supply
- Or both
Determinants of Myocardial Oxygen Demand
Oxygen demand is primarily determined by:
- Heart Rate
- Contractility
- Wall Stress (Preload & Afterload)
Wall stress increases with:
- ↑ Blood pressure
- ↑ Ventricular volume
Therefore, angina therapy reduces:
- Heart rate
- Contractility
- Preload
- Afterload
Increase Oxygen Supply
Agents:
Mechanism:
- ↑ Nitric oxide
- Venodilation → ↓ preload
- Coronary vasodilation
Primary acute relief agents.
Reduce Oxygen Demand
Common agents:
Mechanism:
- ↓ Heart rate
- ↓ Contractility
- ↓ Myocardial oxygen consumption
First-line in chronic stable angina.
—- Dihydropyridine Calcium Channel Blockers
Primarily reduce:
- Afterload
—- Non-Dihydropyridine Calcium Channel Blockers
Reduce:
- Heart rate
- Contractility
- Afterload
Useful when beta-blockers are contraindicated.
Novel / Adjunctive Anti-Anginal Agents
Mechanism:
- Inhibits late sodium current
- Reduces intracellular calcium overload
- Improves myocardial efficiency
Does NOT significantly affect:
- Heart rate
- Blood pressure
Useful as add-on therapy.
Special Situations
Vasospastic (Prinzmetal) Angina:
Avoid pure beta-blockers in vasospasm.
Acute vs Chronic Strategy
Acute Angina:
- Nitroglycerin (sublingual)
Chronic Stable Angina:
- Beta-Blockers first-line
- Consider Ranolazine for refractory symptoms
Clinical Pearls
- Angina = supply-demand mismatch
- Reduce heart rate whenever possible
- Nitrates primarily reduce preload
- Beta-blockers improve mortality post-MI
- Ranolazine improves symptoms without lowering BP
- CCBs preferred in vasospasm
Related
cardio/angina/start.1770944967.txt.gz · Last modified: by andrew2393cns
