====== Anti-Anginal Therapy ======

Angina is a mismatch between myocardial oxygen supply and demand.

Therapy targets either:

  * ↓ Myocardial oxygen demand
  * ↑ Myocardial oxygen supply
  * Or both

→ [[cardio:intro:start|Cardiovascular Pharmacology]]

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===== 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

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===== Increase Oxygen Supply =====

[[cardio:angina:nitrates:start|Nitrates]]

Agents:
  * [[cardio:angina:nitroglycerin|Nitroglycerin]]
  * [[cardio:angina:isosorbide_dinitrate|Isosorbide Dinitrate]]
  * [[cardio:angina:isosorbide_mononitrate|Isosorbide Mononitrate]]

Mechanism:
  * ↑ Nitric oxide
  * Venodilation → ↓ preload
  * Coronary vasodilation

Primary acute relief agents.

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===== Reduce Oxygen Demand =====

[[cardio:beta_blockers:start|Beta-Blockers]]

Common agents:
  * [[cardio:beta_blockers:metoprolol|Metoprolol]]
  * [[cardio:beta_blockers:atenolol|Atenolol]]
  * [[cardio:beta_blockers:propranolol|Propranolol]]

Mechanism:
  * ↓ Heart rate
  * ↓ Contractility
  * ↓ Myocardial oxygen consumption

First-line in chronic stable angina.

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[[cardio:ccb:start|Calcium Channel Blockers]]

---- [[cardio:ccb:dhp|Dihydropyridine Calcium Channel Blockers]]

  * [[cardio:ccb:amlodipine|Amlodipine]]

Primarily reduce:
  * Afterload

---- [[cardio:ccb:non_dhp|Non-Dihydropyridine Calcium Channel Blockers]]

  * [[cardio:ccb:verapamil|Verapamil]]
  * [[cardio:ccb:diltiazem|Diltiazem]]

Reduce:
  * Heart rate
  * Contractility
  * Afterload

Useful when beta-blockers are contraindicated.

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===== Novel / Adjunctive Anti-Anginal Agents =====

[[cardio:angina:ranolazine|Ranolazine]]

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.

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===== Special Situations =====

Vasospastic (Prinzmetal) Angina:

  * [[cardio:angina:nitrates:start|Nitrates]]
  * [[cardio:ccb:start|Calcium Channel Blockers]]

Avoid pure beta-blockers in vasospasm.

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===== Acute vs Chronic Strategy =====

Acute Angina:

  * [[cardio:angina:nitroglycerin|Nitroglycerin]] (sublingual)

Chronic Stable Angina:

  * [[cardio:beta_blockers:start|Beta-Blockers]] first-line
  * Add [[cardio:ccb:start|Calcium Channel Blockers]] or [[cardio:angina:nitrates:start|Long-Acting Nitrates]]
  * Consider [[cardio:angina:ranolazine|Ranolazine]] for refractory symptoms

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===== 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

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===== Related =====

  * [[cardio:hypertension:start|Hypertension]]
  * [[cardio:heart_failure:start|Heart Failure]]
  * [[cardio:arrhythmias:start|Dysrhythmias]]
  * [[cardio:intro:start|Cardiovascular Pharmacology]]