Ischaemic Heart Disease

“Coronary Heart Disease (CHD) from lack of blood supply & cell death”

Risk Factors

• Modifiable:
  • Smoking
  • Obesity
  • Physical inactivity
  • Hypertension,
  • Diabetes mellitus
  • Hyperlipidaemia (modifiable because with proper control IHD can be prevented)
• Non-Modifiable:
  • Sex (male)
  • Advancing age
  • Family history of IHD (MI in 1^st degree relative < 55 years)

Aetiology

• Lack of sufficient blood supply leading to lack of oxygen (ischaemia) with possible cell death → angina and myocardial infarctions

Pathophysiology

• Atherosclerotic plaques on the walls of the arteries narrowing the lumen → imbalance between supply and demand → ↓ blood flow → myocardial hypoxia and accumulation of waste metabolites

Clinical Presentation

• Stable Angina:
  • Central chest pain coming on exertion and alleviated by rest and GTN spray; occurs after walking predictable distances
• Unstable Angina:
  • Pain occurring with increasing frequency
  • Unpredictability, at minimal exertion, or at rest
• Myocardial Infarction
  • Acute crushing central chest pain lasting > 20 minutes
  • May radiate down the left arm
  • Nausea
  • Sweatiness
  • Dyspnoea
  • Palpitations

Investigations

• Bloods:
  • FBC, U&E, glucose, lipids
  • Cardiac enzymes – Troponin- significantly elevated in STEMI, elevated in NSTEMI, and normal in unstable angina
• Imaging:
  • Chest X-Ray – cardiomegaly, widened mediastinum
• Special:
  • ECG
    • In STEMI – hyperacute (tall) T waves and ST elevation within a few hours, T-wave inversion and pathological Q waves follow over hours-days
    • In NSTEMI / Unstable angina – ST depression, T wave inversion

Management

• Conservative Interventions:
  • Stop Smoking
  • Cardioprotective diet
  • Increase physical activity
  • Weightloss
  • keep alcohol consumption within recommended limits
• Immediate interventions for STEMI:
  • Aspirin 300mg; IV morphine; high-flow oxygen; angiography and primary PCI <120 minutes or fibrinolysis <12 hours; anticoagulant until discharge (fondaparinux)
• Immediate interventions for NSTEMI and unstable angina:
  • Aspirin 300mg; second antiplatelet therapy (clopidogrel 300mg); anticoagulation until discharge (fondaparinux); nitrates (GTN) for pain; oral β-blocker (bisoprolol) but if contraindicated use CCB (verapamil)
• Angina:
  • Sublingual glyceryl trinitrate (GTN); aspirin 75mg; β-blocker (bisoprolol, metoprolol, propranolol) or a CCB (verapamil, diltiazem); if CCB or β-blocker not tolerated, consider monotherapy with one of the following: nicorandil, ivabradine, or a long-acting nitrate (isosorbide mononitrate)
• Myocardial Infarction:
  • ACEi (ramipril); angiotensin receptor blocker (ARB) if ACEi is not tolerated (candesartan, losartan); aspirin 75mg; antiplatelet drugs (ADP-receptor antagonists: clopidogrel, ticagrelor); β-blocker (bisoprolol, metoprolol, carvedilol, atenolol, propranolol); statin (simvastatin, atorvastatin

Complications

• Stroke
• Heart Failure
• Consecutive cases of IHD
• Depression
• Anxiety disorders