22. Ischaemic Heart Disease. Stable and Unstable Angina.

Definition

• Decreased blood flow to the heart muscle due to buildup of plaque in coronary arteries.

Classification

• Stable angina
• Unstable angina

Etiology / Predisposition Factors

• Hypertension
• Smoking
• Diabetes
• Obesity
• Poor diet
• High blood cholesterol
• Lack of exercise
• Depression, stress
• Family history
• Excessive alcohol consumption

Pathogenesis

• Narrowing/obstruction of coronary artery lumen:
• Atherosclerosis (main cause)
• Thrombosis/embolism (rare)
• Coronary artery spasm
• Inflammation
• Increased O2 demand:
• Hypertrophy of myocardium
• Tachycardia or tachyarrhythmia
• Decreased cardiac output:
• Aortic valve disease (aortic stenosis, regurgitation)

Symptoms

Stable Angina (Classic Angina)

• Definition: Chest pain/discomfort that occurs during activity or emotional stress, most commonly due to coronary atherosclerosis.
• Pathophysiology:
• 70% coronary artery stenosis (narrowing).
• At rest → blood flow is enough → no symptoms.
• During exertion → increased O2 demand → inadequate blood supply → chest pain.
• Symptoms

• Pain, tightness, or discomfort in chest.
• Often retrosternal, can radiate to:
• Precordial area
• Epigastrium
• Back
• Shoulder
• Arm (especially last 2 fingers of left arm)
• Jaw
• Duration: ~20 minutes, subsides with rest.
• Provoking factors:
• Physical exercise
• Emotional stress
• Hypertension
• Tachycardia or extreme bradycardia
• Hypoglycemia
• Cold weather (causes ↑ myocardial O2 demand)