Wednesday, February 01, 2006

What happens in a heart attack?

This is part ten in the series the heart of the matter. Part nine can be found here and the disclaimer can be found here.

Coronary artery disease is the building up of cholesterol in the wall of arteries of the heart. This build up occurs insidiously. When it reaches a significant degree, it may cause chest pains on effort, relieved by rest (stable angina). This gradual development occurs in the minority of patients. Usually, the slowly progressive cholesterol plaque breaks causing small blood clots in the artery wall to form. If the blood clots are smaller then the vessel size, the clot flows downstream and gets lodged in a small vessel without any consequence to the patients. He may not even know it. However, if the plaque rupture causes a large enough blood clot to form, the size of the blood clot may occlude the whole artery lumen.

Then there is total obstruction to blood flow down that artery, resulting is no nutrition and oxygen to the muscle supplied by that artery. When those tissues are deprived from life-giving oxygen for more then 40 minutes, the cells begin to die, and get rotten. This, results in the chest pains that the patient experience, the ECG changes and also the blood test abnormalities. This then constitutes what is commonly known as a heart attack.

It is important to emphasize that once the artery is occluded, with each passing minute, more muscle cells die and are lost. If blood flow is restored soon, the cells may recover. However, if there is delay in restoring blood flow, the cell death becomes irreversible and the muscle loss becomes permanent. There is then a saying among us medics, "time is heart muscle". If you want us to help save your heart muscle following a heart attack, come as soon as possible. Remember, TIME IS MUSCLE.

In the next part we examine what the signs of a heart attack are.

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