Ischemic heart disease

Ischaemic heart disease is a diseasecharacterized 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 arteriesreduces the supply of blood to heart muscle.

Most ischaemic heart disease is caused by atherosclerosis, usually present even when the arterylumensappear normal by angiography, see IVUS.

What is it?

• Initially there is sudden severe narrowing or closure of either the large coronary arteriesand/or of coronary arteryend branches by debris showering downstream in the flowing blood. It is usually felt as angina, especially if a large area is affected.
• The narrowing or closure is predominantly caused by the covering of atheromatousplaques within the wall of the artery rupturing, in turn leading to a heart attack(Heart attacks caused by just artery narrowing are rare).
• A heart attack causes damage to heart muscle by cutting off its blood supply.

This can cause:

• Temporary damage and pain (ischemia)
• Loss of muscle activity (acute heart failure)
• Permanent heart muscle damage, heart muscle does not grow back (acute myocardial infarction /infarct)
• Long term loss of heart muscle activity (chronic heart failure)
• Cardiac arrhythmias: irregular heartbeat which can be fatal. Most death is due to arrhythmias, usually tachyarrhythmias.
• 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.
• prevent/treat hypertension(high blood pressure)
• Exercise regularly (Exercising the heart muscle strengthens it, like any other)
• Avoid obesity: increasing body fat stores, especially intra-abdominalfat, increases serum cholesterol, triglycerides, insulinrequirements and promotes Diabetes Mellitusplus chronically increases heart muscleworkload.
• Avoid consumption of trans-fatty acids. These are found in any chemically modified fat product, such as margarine, in hydrogenated fats, and especially in superheated fats (such as those used for commercial deep frying). These fats are toxic and should not be consumed in any amount; however, in many western countries, limitation may be the only practical option. Some mono-unsaturated fats are beneficial in reducing the risk of heart disease when consumed in moderation. When consumed in excess, however, other health concerns arise. An increase in polyunsaturated fats is also warranted in most American diets. Dietary cholesterol intake is known to have only limited effect on serum cholesterol.
• Take LDLipoproteincholesterolreducing and HDLipoproteinraising drugs and verfiy both LDLipoproteinparticle counts and quantitative large HDLipoproteinresponse to treatment.
• Avoiding shift work.

Treatment of a heart attack.

The option required depends on the situation.

• Specialised coronary care (the sooner the better); most deaths are due to sudden onset arrhythmias - time is crucial to survival.
• Cardiopulmonary resuscitation(breathing support, pulse and BP monitoring & possible chest compressions).
• A defibrillatorcan stop cardiac arrhythmias.
• An artificial pacemakercan speed up cardiac bradyarrhythmias.
• Drugs such as adrenalinecan increase heart rate and strength of contractions, although also promote tachyarrhythmias.
• Thrombolyticagents can clear away compounding blood clots.
• Anticoagulationcan impede additional blood clots.
• Inotropic drugswill raise blood pressure.
• Unblock arteries with angioplasty("balloon angioplastywith or without stents") or surgery.

After a heart attack

• Possible angioplasty or cardiac surgery.
• Possibly the regular administration of anti-coagulants to prevent further blood clot complications.
• Possibly the administration of drugs to reduce heart arrhythmias although they many also induce arrhythmias.
• Lifestyle modifications are important in prevention of a second MI; increased exercise, reduction of stress, and improved dietary considerations are perhaps most important

ja:虚血性心疾患

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Ischemic+heart+disease Wikipedia article Ischemic heart disease.