How Antioxidants Protects -

Free Radicals and Heart Attacks

A heart attack is different from angina. It is the consequence of an actual blockage of a coronary artery or one of its branches. Heart attacks are not, like angina related to exertion but come on at any time. The pain is similar in nature to angina but is often more severe. It does no pass off on resting, but goes on and on. There is often a terrifying sense of impending death which, unfortunately, is often justified.

When a part of the heart muscle is completely deprived of the blood supply, it becomes swollen and soon dies. This will weaken the heart's action and may sometimes weaken the wall of the heart, but is not necessarily fatal. With luck the dead patch of muscle forms a strong scar and the heart continues to beat satisfactorily, although capable of less powerful action than before. Sometimes this process is repeated several times, and with each attack the heart is damaged further. In such cases, heart failure the inability to keep the blood circulating adequately is likely to occur.

Modern research indicates that, quite apart from the effect of free radicals in causing atherosclerosis in the coronary arteries, they have another sinister role to play in heart attacks. this research has shown that a further and most important effect of free radicals occurs, not at the time of the blockage, but when the damaged tissue, especially that around the dead One, is trying to recover by widening nearby blood vessels. This response is called 'reperfusion' and it is during this period that more oxygen becomes available and the maximum secondary danger from the radicals occurs.

This fact was dramatically illustrated in a paper published in the Lancet in April 1993. free radical research has now progressed to the stage at which evidence of the presence of free radials can actually be obtained by analyzing a small sample of the blood emerging in a vein from the area concerned. Such blood is examined by a very advanced method known as 'electron paramagnetic resonance spectroscopy'. Samples have to be stored at very low temperatures in liquid nitrogen until they can be examined.

The paper in the Lancet described the case of a 61-year-old man who was treated in hospital two and a half hours after having a heart attack. A special kind of X-ray called 'angiography' showed that one of has coronary arteries was blocked. A fine tube ( catheter) with a small balloon at one end was passed into the affected artery, pushed along to the obstruction, and the balloon inflated. The artery was successfully opened up. So far, the matter was routine. This procedure of coronary artery balloon angioplasty is a day-to-day routine, too common place to be reported in a medical journal. What was different about this case was that, before passing the balloon catheter, a second, very narrow-bore, tube had been passed into the patient’s heart so that the tip to near the opening of the vein the coronary sinus that returns the coronary artery blood to the circulation. This allowed samples of the blood passing through the affected area to be taken throughout the procedure. There were immediately frozen to await spectroscopy the procedure. These were immediately frozen to await spectroscopy.

Unfortunately, an hour later, the coronary artery closed again and the procedure had to be repeated. Again, samples of blood emerging from the affected area were obtained and processed. This time, the artery remained open long-term, and all was well. When the blood samples were studied by electron paramagnetic resonance spectroscopy it was found that, in both episodes, each time the artery was opened up a flood of free radicals poured out of the area.

This was an important confirmation of the widely held view that a great deal of the damage that occurs into eh course of a heart attack is caused by free radicals that are released during the recovery phase, whether from the body’s natural recovery response by opening up nearby blood vessels, or whether due to medical intervention. The experts currently believe that it is the increased availability of oxygen, at this point, that initiates the production of free radicals.