Lecture on Angina

Definition and Cause

• Angina Pectoris: Derived from Latin words "angere" (to strangle) and "pectus" (chest).
• Meaning: Strangling of the chest due to reduced blood flow (ischemia) causing lack of oxygen to heart muscle.

Types of Angina

1. Stable Angina (Chronic angina)

• Cause: Usually occurs when ≥70% stenosis (plaque buildup) in an artery.
• Triggers: Exertion or emotional stress.
• Symptoms: Chest pain relieved by rest.
• Underlying Cause: Often atherosclerosis of coronary arteries.
• Other Causes:
  • Hypertrophic cardiomyopathy.
  • Aortic stenosis or hypertension causing thicker heart muscle needing more oxygen.
• Ischemia: Subendocardial, triggered by release of adenosine and bradykinin causing nerve stimulation.
• Pain Description: Pressure or squeezing, radiating to left arm, jaw, shoulder, back; may include shortness of breath and diaphoresis.

2. Unstable Angina

• Characteristics: Pain during rest and exertion; does not go away easily.
• Cause: Rupture of atherosclerotic plaque with thrombosis.
• Risk: High risk of myocardial infarction (heart attack).
• Ischemia: Subendocardial.

3. Vasospastic Angina (Prinzmetal angina)

• Cause: Coronary artery vasospasms causing severe constriction.
• Occurrence: Can happen at rest; not linked to exertion.
• Ischemia: Transmural, affecting all heart wall layers.
• Mechanism: Involves vasoconstrictors like thromboxane A2.

Clinical Features and Diagnosis

• Stable & Unstable Angina ECG: ST segment depression.
• Vasospastic Angina ECG: ST segment elevation.
• Reversibility: Injury is reversible in all types; differs from myocardial infarction.

Treatment

• Common Treatment: Nitroglycerin (vasodilator) for all types.
• Vasospastic Angina: Also treated with calcium channel blockers.

Conclusion

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