Ischaemic heart disease

Ischaemic heart disease is a disease characterized by reduced blood supply
to the heart. It is the most common cause of death in most western
countries.

Ischaemia means a "reduced blood supply". The coronary arteries supply blood
to the heart muscle and no alternative blood supply exists, so a blockage in
the coronary arteries reduces the supply of blood to heart muscle.

Most ischaemic heart disease is caused by atherosclerosis.

What is it?

   * Initially there is narrowing of coronary arteries causing angina.
   * The narrowing is mostly caused by fatty plaques lining the wall of the
     artery.
   * Sometimes a fatty plaque will rupture leading to a heart attack. (Heart
     attacks caused by simple narrowing are relatively uncommon).
   * A heart attack causes damage to heart muscle by cutting off its blood
     supply.

This can cause:

   * Temporary damage and pain (ischaemia)
   * Loss of muscle activity (acute heart failure)
   * Permanent heart muscle damage (acute myocardial infarction /infarct)
   * Long term loss of heart muscle activity (chronic heart failure)
   * Cardiac arrhythmias: irregular heartbeat which can be fatal.
   * Other structural damage to the heart including damaged heart valves,
     actual perforation of the heart and a thin walled fibrous floppy heart.

Prevention. Prevent or delay atherosclerosis.

   * Do not smoke.
   * Treat hypertension (high blood pressure)
   * Exercise regularly (Exercising the heart muscle strengthens it, like
     any other)
   * Avoid obesity: a large body puts unnecessary strain on the heart and
     increases serum cholesterol and triglycerides.
   * Avoid excess saturated fat in the diet. Some unsaturated fats may be
     beneficial in reducing the risk of heart disease when consumed in
     moderation. Dietary cholesterol is shown to have a modest effect on
     serum cholesterol.
   * Take cholesterol reducing drugs.

Treatment of a heart attack. Which of these options are required depends on
the situation.

   * Specialised coronary care (the sooner the better).
   * Cardiopulmonary resuscitation (heart massage).
   * A defibrillator can revert cardiac arrhythmias.
   * An artificial pacemaker can prevent cardiac arrhythmias.
   * Drugs such as adrenaline can increase heart rate.
   * Thrombolytic agents can clear away the causative blood clot.
   * Anticoagulation can prevent additional blood clots.
   * Inotropic drugs will raise blood pressure.
   * Unblock arteries with surgery or angioplasty ("balloon angioplasty")

After a heart attack

   * Possible cardiac surgery.
   * Possibly the regular administration of anti-coagulants to prevent
     further arrhythmias
   * Possibly the regular administration of drugs to control heart rhythm.
   * Increase exercise within limits of safety (see prevention) to train the heart.