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• Ischaemia


  An inadequate supply of blood to a tissue resulting in insufficient supply of oxygen and other metabolic needs for that tissue
• Infarction

  Cell / Tissue Necrosis (death) caused by an inadequate supply of blood carrying oxygen and other metabolic needs
• Causes of artery blockage


  • Atheroma
  • Thrombus
  • Spasm
  • Embolus
  • Vasculitis
• Factors determining myocardial oxygen supply

  List not provided
• Factors determining myocardial oxygen demand

  List not provided
• Stable Angina


  Central chest pain whenever he walks fast going for the bus, pain goes away on stopping
• Diagram for patient with Angina


  Arteriole diameter and blood flow
• Nitrates


  • Relax vascular smooth muscle - some reduction of afterload
  • Relax veins - reduction in central venous pressure, reduced preload
  • In healthy subjects - stroke volume reduces, venous pooling on standing, postural hypotension and dizziness
  • Therapeutic doses have less effect on small resistance arteries than on veins
• Mechanism of Action of Nitrates


  1. Nitrates are metabolised releasing NO

  2. Activates guanylyl cyclase - increases cGMP

  3. Dephosphorylation of myosin light chains

  4. Reduces cytoplasmic Ca2+

  5. Relaxation of smooth muscle
• Adverse Effects of Nitrates


  • Postural hypotension
  • Headache
• GTN


  Sublingual administration - effects in minutes, rapidly inactivated by hepatic metabolism
• Immediate drug treatment of Myocardial Infarction


  1. A - to relieve hypoxia: Oxygen (not routinely used, only if oxygen saturation reduced)

  2. B - pain relief: Morphine/diamorphine with an antiemetic (Relieves pain and nausea, Venodilation)

  3. C - Reduce cardiac workload and improve perfusion: Nitrates - GTN (Vasodilator, Reduces cardiac work)

  4. D - Reduce risk of another infarction: Anti-platelet - Aspirin, Clopidogrel (Prevent further clot formation)
• Subsequent drug treatments for Myocardial Infarction


  • A - to improve myocardial perfusion and reduce risk of arrhythmias: Beta-blocker (Improves myocardial perfusion by lengthening diastole, Class II antiarrhythmic drug)
  • B - improves survival and useful if risk of heart failure/left ventricular dysfunction: ACE inhibitor - captopril
  • C - protection from thrombus in at risk patients: Anticoagulants - Heparin (May prevent reinfarction)
  • D - other useful drugs: Nitrates, Antiarrhythmics, Statin - lipid lowering