Coronary Heart Disease (Part 2) |
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Any person who has sustained such a myocardial infarction (heart attack) is subject to a risk which may be life-threatening immediately; he should be in medical hands, preferably in a hospital, as soon as possible. The major risks are two-fold. Firstly, that much damage to the heart muscle will interfere with its function as a pump. Fortunately, extensive damage is relatively unusual, and when it occurs it is usually later, when medical help can be offered. The second type of complication is more subtle. As already explained, the heart has an electrical system for its regular sequence of timing and coordination. Damaged heart muscle causes electrical instability and electrical currents flow between the normal and the damaged muscle. This may lead to abnormal heart rhythms which may be inappropriately fast or slow, or to a loss of the normal electrical co-ordination. Even when the amount of actual physical damage is very small, the interference with the timing can be severe enough to make it difficult to achieve a satisfactory pumping action. This is similar to a car engine, where even a mechanically perfect engine cannot fire properly in the absence of a satisfactory electrical system —battery, coil, distributor, leads and sparking plugs; if the timing is wrong, the engine will misfire, and if the battery is flat, the engine will not function at all. For this reason much attention is paid to monitoring the electrical function of the heart after a myocardial infarction, even when the physical damage is relatively minor. This is best carried out in a specialized unit often referred to as a 'coronary core unit' (CCU), where there is the right type of equipment and staff, both medical and nursing, specially trained to recognize abnormalities quickly and early, before they become a serious problem. Quick effective treatment in the early stages may minimize or completely avoid later life-threatening abnormalities in the rhythm of the heart. Muscle damage caused by a myocardial infarction ritually heals, leaving only a scar in much the same way that a broken bone heals and regains its normal function. Naturally, during the healing phase one avoids stressing the heart, as one would avoid walking on a broken leg. Bed rest, the use of certain drugs to calm the person (sedation) and sleep are therefore advised initially, and this can be satisfactorily supervised in a CCU, while the electrical rhythm is monitored and treated as necessary., There is certain amount of medical controversy at present as to whether patients are best nursed in a CCU in a hospital environment or at home in familiar surroundings; the latter avoids the emotional stress by transport and by being in hospital. Most of the risks occur in the first few menacing hours and it is during this period that the patient should ideally be in medical care. He may well not be, however, either he does not himself recognize the problem or because no immediate care is available. It is fair to say that if the patient has taken a long time to get medical hands —say, 18-24 hours —then most of has pasted, and at this stage home care is reasonable, assuming that there are no obvious complications. Every person who has sustained a myocardial infarction should be encouraged to return to a normal life, although it may take several months to reach that point. As previously stated, the damage heals, leaving only a scar and, in a majority of patients, the pump function of the heart will remain normal. The reserve of the normal heart is sufficient to compensate for some loss of function. In only a few patients will the pump be impaired, so as to require medical treatment. Occasionally, if the damage is extensive, but restricted to only one section or part of the heart, surgery may help. Some people who do not suffer from an infarction due to a complete coronary artery block may, as indicated earlier, suffer from cardiac pain due to deficiency of blood supply caused by narrowing of the arteries. A variety of medical treatments are available which, while not actually relieving arterial narrowing, allow the heart muscle to use what fuel it does receive in the most efficient way. When medical treatment fails and life-style is sufficiently impaired, surgery is now available to provide mechanical solutions to mechanical problems. More money has been spent on research into the basic cause of this narrowing of the arteries than any other medical subject except perhaps on cancer and yet, although theories abound, the problem remains largely obscure. One theory relates the intake of fatty substances such as cholesterol to their level circulating in the blood, and many people believe that the level of cholesterol in the blood is related to an increase in the fatty deposits which make up much of the thickening of the artery walls which narrows them. Some authorities have said that eating food containing a rich supply of cholesterol —such as eggs—or eating food which contains what are called 'saturated fatty acids'—such as animal fats like butter—which seem to raise the cholesterol level in the blood, can lead to an Increase in disease of the arteries. A second basic cause which has been proposed is that the initial abnormality is damage to the inside of the artery wall by a cause as yet unknown, and that, after this damage has occurred, there is a deposit of phatelets, small bodies circulating in the blood which aid normal clotting. These platelets serve as the starting point for subsequent deposits of blood clots and division of the cells within the artery wall, which gradually lead to its thickening and narrowing. Although some of the evidence for this theory is rather indirect, it provides a basis for treatment to prevent the depositing of platelets. A variety of other causes have been advanced over ears, including eating too much sugar and drinking soft water, but the data for many studies is sting and there is still no clear evidence that any factor is of overwhelming importance. |
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