Cardiovascular System >
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 1st 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
- ECG
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